Data Access and Middle-Tier... Control Library or Web Services

TheMSsForum.com: The Microsoft Software Forum

The MSS Forum ‹ Ado
- Archive
  - Biz
  - MCSE
  - CRM
  - Drivers
  - Framework
  - ADO
  - ASP
  - Compact
  - Forms
  - Dotnet
  - C#
  - VB
  - FontpageGen
  - Excel
  - WorkSheet
  - Exchange
  - Setup
  - Fox
  - Fontpage
  - ASP
  - IIS
  - Entourage
  - Money
  - Messanger
  - PocketPC
  - Powerpoint
  - Project
  - Publisher
  - Excel
  - VB
  - Security
  - Portal
  - Services
  - SQLServerDev
  - SVCS
  - SQLServer
  - VB
  - VC
  - MFC
  - ExcelGen

- Previous
  - 1
    - How to use DataSet.xsd with ADO.NET DataSet?? In VS 2005 I've used the Data Source Configuration Wizard to create a MyDataSet.xsd, but I'm lost on how to get anything out of the .xsd into a workable ADO.NET dataset?? Any suggestions? Thanks, Rob. Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121530
  - 2
    - Insert ForeignKey of parent DataGrid in child Hi, I have two dataGrids bound to two different datasets, which relate to each other as parent/child. The primary key/foreign key columns are hidden in the DataGrid. If I select a Parent the corresponding child's are displayed. I want to add a row to the child, with the currently selected parents primary key as foreign key. How can I insert the right foreign key? I tried the DataTable "RowChanging" and "RowChanged" event, but I got a NOT-NULL violation from the DataGrid. I tried to use a DefaultValue and then changed this DefaultValue within the RowChanging-Event, that caused an error ("Can't change default value in RowChanging event."). I miss a "NewRow" event in DataGrid or something like that, so that I can simply edit the new row and insert the proper foreign key. My current solution is to catch the OnMouseUp Event on Parent DataGrid and set child Foreign key column Default Value to the selected parent Primary Key value. But this is more a hack then a Solution: private void dataGridBenchmark_MouseUp(object sender, System.Windows.Forms.MouseEventArgs e) { dataSetBenchmarks1.BenchmarkVersion.Benchmarkprogramm_IDColumn.DefaultValue=dataSetBenchmarks1.Benchmarkprogramm[dataGridBenchmark.CurrentRowIndex].Benchmarkprogramm_ID; } The problem is, that the user has to click the parent and can't use the keyboard. Any ideas? Thanks! Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121524
  - 3
    - DataSets designed in wizard Greetings, I am new to this and have some problems. I created a dataset using the vs2005 GUI and want to load the dataset using code in the back end I have: XmlDocument xmlDoc = new XmlDocument(); dsSampleTableAdapters.tblSamplesTableAdapter sample = new dsSampleTableAdapters.tblSamplesTableAdapter(); sample.GetSampleData(sample_id); //DataSet ds = new DataSet // dsSample ds = new dsSample // xmlDoc = ds.GetXml(); Console.WriteLine(xmlDoc); return xmlDoc; The problem is that I am not sure where the sample.getSampleData is acutally storing the data. I tried to set ds = sample.getSampleData moving the new dataset lines above that obviously. All I need to do is to retrieve the dataset I created in the gui and return it as XML to a web service or as a custom object to a thick client. Any help is appreicatied. Thanks Roger Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121522
  - 4
    - HELP on New request is not allowed to start because it should come I am getting the following error in my application: New request is not allowed to start because it should come with valid transaction descriptor. This is happening under a very singular circustance: I have just migrated to SQL server 2005 and ASP.NET 2.0. It is not happening all the time. It happens occasionally in all my pages that are working correctly, and once in a while, throw this kind of exception. When it happens, it happens on the first Connection.Open of the page. I am using Windows 2003 Enterprise. Please, somebody help me. I trusted Microsoft, migrated all my systems and now these errors are killing my application. And the message is a kind of message that doesn`t give me any clue of what is wrong. Thanks a lot. Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121517
  - 5
    - Problem with deleting a DataRow in a DataTable Hi all: I am allowing a user to delete (indirectly) a row (representing a floor in a building) from a data table (representing the floors in a building). To delete the floor, the user displays the appropriate floor data and clicks the delete button. The delete floor button click invokes the delete_floor function, passing the floor number. delete_floor first locates the appropriate row in the floor DataTable. When the floor is found (it would be an error if it were not), the row is marked for deletion, the deleted flag is set, and the for loop is exited. If the deleted flag is set, the table's AcceptChanges method is invoked and the XML data set (containing the table) is saved. The table is then retrieved, the remaining floors are renumbered, the AcceptChanges method is invoked again, and the XML data set is saved again. Problem: The row is not deleted. Following is the delete floor function - dwds is declared as private DeconUtilities.DW_DataSet dwds = new DeconUtilities.DW_DataSet ( ) ; Thoughts appreciated. TIA Gus // ************************************************* delete_floor public bool delete_floor ( int floor ) { bool deleted = false ; DataRow row ; DataTable table = dwds.floor_data_table ; if ( table != null ) { for ( int i = 0; ( i < table.Rows.Count ); i++ ) { row = table.Rows [ i ] ; if ( floor.Equals ( Convert.ToInt32 ( row [ "floor" ] ) ) ) { if ( deletion_confirmed ( floor ) ) { row.Delete ( ) ; deleted = true ; } break ; } } } if ( deleted ) { table.AcceptChanges ( ) ; dwds.save_XML_data_set ( ) ; table = dwds.floor_data_table ; if ( table != null ) { for ( int i = 0; ( i < table.Rows.Count ); i++ ) { row = table.Rows [ i ] ; row [ "floor" ] = ( i + 1 ) ; } table.AcceptChanges ( ) ; dwds.save_XML_data_set ( ) ; } } return ( deleted ) ; } Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121515
  - 6
    - VS2005 / Stored Procedure First time through on this, so I could use some help. I'm having difficulty getting data from a stored procedure into a DataGridView control in a Windows form. I'm using VS2005 and C#. My test program has two DataGridView controls. One is populated via SQL generated via drag/drop/property settings, and works like a charm. I'm trying to do the same thing with the other, but using a stored procedure as the source of the data. I know the stored procedure works, and it returns the same data as the SQL in the first control. Nothing appears in the control at runtime. At design time, there are no columns automatically added to the control. So, I tried to add them via the Columns collection. No column names appeared in the DataPropertyName dropdown on the property sheet for my new columns. I entered the field name for each of the new columns, but still no luck. Could someone provide a 'how to' on this, or maybe point me to where the explanation is in the documentation? Thanks in advance, Ben -- bf001removethis@abovetheline.biz Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121511
  - 7
    - Absolute Beginner Question Hi, My apologies if this is a simple question but I'm having a hard time making any progress so... I'm looking at VB ADO.net, moving from ADO / Access development. I've created a bog standard windows app in VB2005 Express and having read some of the basics am attempting to create a connection to a SQLS2000 db on my network and display the contents of a table in a listbox on a my form. As I understand it, the steps involved are: * create a connection to the database (done, I think) * create a command object containing the action that i wish to perform (SELECT statement) * execute the command object and return the reults set to a DataReader object as read-only which I can use to populate the listbox on my form. I can create the connection and the command object but I'm not quite sure where the datareader object comes in and how exactly I use it... Please see code below. I appreciate that this is a very simple question, however any and all advice is gratefully received - be that links, pointers or so on. Thanks Chris. ************************** Imports System.Data.SqlClient Public Class Form1 Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load Dim TLCConn As SqlClient.SqlConnection Dim contCMD As SqlClient.SqlCommand TLCConn = New SqlConnection TLCConn.ConnectionString = _ "Data Source=SQL;Integrated Security=SSPI;Initial Catalog=TLCBackup" TLCConn.Open() contCMD = New SqlCommand contCMD.Connection = TLCConn contCMD.CommandText = "SELECT MovementNo, ContainerNo, DateIn, DateOut " & _ "FROM Stock " & _ "WHERE dateout is null " & _ "ORDER BY MovementNo" End Sub End Class Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121509
  - 8
    - DataGridView reordering in design view Hi folks, I'm developing an desktop app that uses a DataGridView. This is bound to a BindingSource derived from an object. I have just added a couple of public properties to the class and added these columns to the DGV. They display just fine and as I expect at runtime, but whenever I view the form in design view the columns are reordered. However, they still display correctly at runtime. Only if I Edit Columns on the DataGridView and then Ok that dialog does the reordering affect the runtime view. Any ideas/similar experiences. For now I have locked the controls on the form which is making it behave for the moment, but if I need to change the form in any way I need to unlock it and again the same problem at design time. Oh this has only just started happening, was working fine for the last two weeks. Cheers Simon Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121503
  - 9
    - DataAdapter Mapping only works for the first two tables. Hi, I am writing an application where the select command returns multiple record sets and write the infomation to a xml file. I used typed dataset to store the returned info and use the dataset.writexml command to save the data to a xml file. Oh one more thing I am used the DAB (data application block) to fill the dataset. I tried the same solution with the "Northwind" database but no luck. Here's my code: SQL stroed proc: CREATE PROCEDURE [dbo].[proc_name] @EmployeeID INT AS SELECT * FROM Employees WHERE EmployeeID = @EmployeeID; SELECT * FROM EmployeeTerritories; SELECT * FROM Territories; GO Here's the code that fills the dataset: TestDto dto = new TestDto(); //xsd contains the tables def string[] tableList = new string[3] ; tableList[0] = "Employees"; tableList[1] = "EmployeeTerritories"; tableList[2] = "Territories"; SqlHelper.FillDataset("connectionstring", CommandType.StoredProcedure, "proc_name", dto, tableList, new SqlParameter("@EmployeeID", 1) ); dto.WriteXml(@"C:\xxx.xml"); When I look at the "xxx.xml" file i see the table mapping being done for "Employees" and "EmployeeTerritories" but "Territories" mapping is set to "Table2"...Crazy!!!! Can someone please tell me why? Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121494
  - 10
    - Problem with strongly typed data sets Hi! Does anyone know of a way to tweak the code generator for the strongly typed data sets to allow nullable types? For example, the datatype "decimal" should be generated as "decimal?" instead. regards Carl Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121491
  - 11
    - Concurrency Violations in SqlCeDataAdapter Hi all, I am having a problem with using SqlCeDataAdapter to update the database. I am working with the dataset and the data adapter to do my Select,Insert,Update,Delete . The Dataset holds the results of the select commmand and I store the adapter in a Hashtable .When the user does an insert ,I retrieve this adapter from the Hashtable , set the Insert command and update the adapter.This works fine and I am able to insert multiple rows . The problem appears when I try to update a newly inserted row , one that was not displayed in the search results when the application loaded this form. Then I get a Concurrency violation , No records updated exception . The same goes for deleted rows . Can some one tell me what is happening ?.Also how do I go about solving this problem?. Thanks, Raja Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121477
  - 12
    - define dataset column for timestamp data type in MS SQL server All, What kind of data type should I use to definde a timestamp (row version) data-type in MS SQL Server for a column in a dataset? I tried to define it as byte[], but MSDataSetGenerator is giving me the "unable to convert xml file content to a DataSet" error. Thanks, John Yung Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121476
  - 13
    - Problem Connecting To Access Database I created some very simple ASP.NET applications - form data is entered into an Access database. There are 4 of these apps - all similar in nature and even connect to the same database just different tables via stored queries. All of the apps were working fine on the web server. Then I recently noticed that a few all of the sudden stopped working. I checked thru the code on my local machine - where I originally created them, but didn't see any differences between the ones that worked and the ones that didn't. However when I attempted to run in debug mode on my local system I started receiving the same error message for all of them. If I rebuild and copy back to the server some of them run fine, while others still do not. - there doesn't seem to be an rhyme or reason. Here is the error message I receive for one that works on the web server, but not locally. Exception Details: System.Data.OleDb.OleDbException: No error information available: REGDB_E_CLASSNOTREG(0x80040154). Source Error: Line 90: // try Line 91: //{ Line 92: oleHr.Open(); Line 93: oleInsert.Parameters["firstName"].Value = txtFirstName.Text; Line 94: oleInsert.Parameters["lastName"].Value = txtLastName.Text; Source File: c:\inetpub\wwwroot\con020\default.aspx.cs Line: 92 Stack Trace: [OleDbException (0x80040154): No error information available: REGDB_E_CLASSNOTREG(0x80040154).] [InvalidOperationException: The 'Microsoft.Jet.OLEDB.4.0' provider is not registered on the local machine.] System.Data.OleDb.OleDbConnection.CreateProviderError(Int32 hr) System.Data.OleDb.OleDbConnection.CreateProvider(OleDbConnectionString constr) System.Data.OleDb.OleDbConnection.Open() con020.WebForm1.cmdSign_Click(Object sender, EventArgs e) in c:\inetpub\ wwwroot\con020\default.aspx.cs:92 System.Web.UI.WebControls.Button.OnClick(EventArgs e) System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler. RaisePostBackEvent(String eventArgument) System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) System.Web.UI.Page.ProcessRequestMain() +1292 Does anyone know what could be causing this inconsistent behavior? -- Message posted via DotNetMonster.com http://www.dotnetmonster.com/Uwe/Forums.aspx/dotnet-ado-net/200511/1 Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121475
  - 14
    - ADO.net is giving me the WRONG date here... I have a table with a datetime column. Then, in my C# program I open a datatable with that column in it and access it with the following syntax: dt.rows[i]["datefield"] Now, when I look at the data in the table from say Enterprise Manager, the row in question has an "11/17/2005 8:15:29 am" in it. But, my ado.net code yields a "11/17/2005 8:15:28 am". This isn't for all the rows in the datatable, only a few. Is there some sort of "conversion" that goes on between .net and SQL Server? Is there some rounding going on? Any help would be much appreciated. Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121474
  - 15
    - Nasty DataView bug Hi, everyone, I ran into a serious bug upgrading to VS2005, and very easy to reproduce. It goes like this: 1. Filter a DataView 2. Get a reference to a DataRowView 3. Clear the filter - the reference to the DataRowView has changed to a completely different row! This is not a problem in .NET 1.1 - only in 2.0. The code to reproduce the problem is below. Please help! Thanks, Bob L. Dim oTable As DataTable Dim oView As DataView Dim oRowView As DataRowView 'Build simple table oTable = New DataTable oTable.Columns.Add("ID", GetType(Integer)) oTable.Rows.Add(New Object() {12}) oTable.Rows.Add(New Object() {25}) 'Construct & filter DataView oView = New DataView(oTable) oView.RowFilter = "ID=25" 'Get a reference to the found item and display the ID oRowView = oView.Item(0) MsgBox(oRowView.Item(0)) 'ID = 25 oView.RowFilter = "" 'Show the same ID again 'In 1.1 this line of code still shows 25 - correct. 'In 2.0 it shows 12 - wrong! MsgBox(oRowView.Item(0)) Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121473
  - 16
    - Serviced Component, Excel and OleDbConnection.Open I'm using the OleDbConnection object to retrieve the contents of an Excel Worksheet as a DataSet. This works fine when testing the MyExcel.GetMonthly() method call. When I call MyExcel.GetMonthly() from a Serviced Component, it bombs. Code snippet: OleDbConnection cn = new OleDbConnection(CnString); cn.Open(); <-- Error occurs here In an effort to isolate the problem I created a new class and called MyExcel.GetMonthly() from it. Without ServicedComponent inheritence it works fine. With ServicedComponent inheritence it crashes with: A condition has occurred that indicates this COM+ application is in an unstable state or is not functioning correctly. Assertion Failure: !m_punk Server Application ID: {6E4E5709-D807-46DD-819E-2B3D150FC547} Server Application Instance ID: {C73018C7-1BB0-4DB2-A9DB-4D9E22521507} Server Application Name: MSRBLL The serious nature of this error has caused the process to terminate. COM+ Services Internals Information: File: d:\qxp_slp\com\com1x\src\comsvcs\jit\jit.cpp, Line: 858 Comsvcs.dll file version: ENU 2001.12.4414.258 shp Any thoughts? Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121472
  - 17
    - DataTable.Load() fills in schema!! Hi there, I was loading a datatable with Dataadapter's Fill() method. Then, I could add a new record to the datatable and it won't complain about not null columns until I called the Dataadapter's Update() method. That's OK for me. Now I am experimenting with the Load() method of a datatable (.NET 2.0) to fill it from a datareader, but as soon as I add a new row, I get an exception from the datatable complaining about the not null columns. Is there a way to avoid that? Best Regards, -Benton Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121469
  - 18
    - WITH NOWAIT And SqlConnection's InfoMessage Is there any possible way to get messages asynchronously sent from a stored procedure running on SQL Server 2000, back to ADO.Net, in realtime (or at least somewhat close to it)? After much experimenting, I am left to say "no"... it is not possible. Although it would appear it should be. On SQL Server, the RAISERROR command has an available "WITH NOWAIT" option. According to the documentation, this "sends messages immediately to the client". This, combined with the SqlConnection object's InfoMessage event, should theoretically allow one to receive these messages asynchronously, while the proc is executing. I assume this doesn't work because ExecuteNonQuery does not fire this event until after it (and thus the stored procedure) has completed. Here's some sample code... first my stored proc: RAISERROR('1',10,1) WITH NOWAIT RAISERROR('2',10,1) WITH NOWAIT RAISERROR('3',10,1) WITH NOWAIT And the C# code: private void RunProc() { this.listBox1.Items.Add("Proc started..."); try { this.sqlConnection1.Open(); this.sqlCommand1.ExecuteNonQuery(); } finally { this.sqlConnection1.Close(); } this.listBox1.Items.Add("Proc complete..."); } private void sqlConnection1_InfoMessage(object sender, System.Data.SqlClient.SqlInfoMessageEventArgs e) { this.listBox1.Items.Add(e.Message); } Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121467
  - 19
    - Why am I getting ForeignKeyConstraint requires child key value error? Hello, Here is the error message; ---------------------------- Exception Message: ForeignKeyConstraint Lkp_tbl040Cmpt_lkp302SensorType requires the child key values (5) to exist in the parent table. ---------------------------- I am encountering this error when I try to insert records into table 'tbl040Cmpt' using the DataSet1.Tables("Table").Rows.Add(row) The relevant data structure goes like this the table 'tbl040Cmpt' contains a field that stores the value from lookup table 'lkp302SensorType'. Here is the relationship that exists in the Dataset; \\ Me.Relations.Add("Lkp_tbl040Cmpt_lkp302SensorType", Me.Tables("lkp302SensorType").Columns("pkSensorTypeId"), Me.Tables("tbl040Cmpt").Columns("cmSmallint06")) // Here is the 'lkp302SensorType' lookup table; \\ CREATE TABLE [lkp302SensorType] ( [pkSensorTypeId] [smallint] IDENTITY (1, 1) NOT NULL , [SensorType] [varchar] (50) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL , [Ord] [tinyint] NOT NULL CONSTRAINT [DF_lkp302SensorType_Ord] DEFAULT (0), [Hide] [bit] NOT NULL CONSTRAINT [DF_lkp302SensorType_Hide] DEFAULT (0), CONSTRAINT [PK_lkp302SensorType] PRIMARY KEY CLUSTERED ( [pkSensorTypeId] ) WITH FILLFACTOR = 90 ON [PRIMARY] ) ON [PRIMARY] GO // Here are table 'tbl040Cmpt' \\ CREATE TABLE [tbl040Cmpt] ( [pkComponentId] [char] (36) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL CONSTRAINT [DF_tbl040Cmpt_pkComponentId] DEFAULT (newid()), [fkDevice] [char] (36) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL , [fkComponentType] [int] NOT NULL , [ComponentDescription] [varchar] (100) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL , [QuanSharingConfiguration] [tinyint] NOT NULL , [QuanConfigured] [tinyint] NOT NULL CONSTRAINT [DF_tbl040Cmpt_QuanConfigured] DEFAULT (0), [QuanActuations] [tinyint] NOT NULL CONSTRAINT [DF_tbl040Cmpt_QuanActuations] DEFAULT (1), [cmVarchar01] [varchar] (50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL , [cmVarchar02] [varchar] (50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL , [cmVarchar03] [varchar] (50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL , [cmVarchar04] [varchar] (50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL , [cmVarchar05] [varchar] (50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL , [cmVarchar06] [varchar] (50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL , [cmNumeric01] [numeric](5, 3) NULL , [cmNumeric02] [numeric](5, 3) NULL , [cmNumeric03] [numeric](5, 3) NULL , [cmNumeric04] [numeric](5, 3) NULL , [cmNumeric05] [numeric](5, 3) NULL , [cmNumeric06] [numeric](5, 3) NULL , [cmNumeric07] [numeric](5, 3) NULL , [cmBit01] [bit] NULL , [cmBit02] [bit] NULL , [cmBit03] [bit] NULL , [cmBit04] [bit] NULL , [cmBit05] [bit] NULL , [cmBit06] [bit] NULL , [cmBit07] [bit] NULL , [cmBit08] [bit] NULL , [cmBit09] [bit] NULL , [cmBit10] [bit] NULL , [cmBit11] [bit] NULL , [cmSmallint01] [smallint] NULL , [cmSmallint02] [smallint] NULL , [cmSmallint03] [smallint] NULL , [cmSmallint04] [smallint] NULL , [cmSmallint05] [smallint] NULL , [cmSmallint06] [smallint] NULL , [cmSmallint07] [smallint] NULL , [cmSmallint08] [smallint] NULL , [cmTinyint01] [tinyint] NULL , [SooOrder] [numeric](5, 3) NULL , [SooPrecedent] [numeric](5, 3) NULL , [SooDelay] [numeric](5, 3) NULL , [SooNote] [varchar] (255) COLLATE SQL_Latin1_General_CP1_CI_AS NULL , [cmUserNote] [varchar] (255) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL , [cmCreatedOn] [smalldatetime] NOT NULL , [cmCreatedBy] [varchar] (25) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL , [cmEditedOn] [smalldatetime] NOT NULL , [cmEditedBy] [varchar] (25) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL , [cmrowversion] [timestamp] NOT NULL , CONSTRAINT [PK_tbl040Cmpt] PRIMARY KEY CLUSTERED ( [pkComponentId] ) WITH FILLFACTOR = 90 ON [PRIMARY] , CONSTRAINT [FK_tbl040Cmpt_lkp202ComponentType] FOREIGN KEY ( [fkComponentType] ) REFERENCES [lkp202ComponentType] ( [pkComponentTypeId] ), CONSTRAINT [FK_tbl040Cmpt_tbl030Devi] FOREIGN KEY ( [fkDevice] ) REFERENCES [tbl030Devi] ( [pkDeviceId] ) ON DELETE CASCADE NOT FOR REPLICATION ) ON [PRIMARY] GO // Here is selected code that causes the error' \\ Private Sub InsertCylnSensor(ByVal s As String) 'Create a data row (collection of fields) Dim row As DataRow = _dataSet1.Tables(_currentTable).NewRow 'MessageBox.Show("Insert is called for: " & s) Try ' Data entered automatically row("pkComponentId") = Guid.NewGuid.ToString 'row("fkDevice") = _pkDeviceIdForFkAndParameter row("fkDevice") = f030Devi._pkDeviceIdForFkAndParameter row("fkComponentType") = 7 'Motion sensor ' ClipDriver - Clip Driver_1 Sensor_1 _ A(??) row("ComponentDescription") = _ Me.txtComponentDescription.Text.ToString & _ " - " & _componentTypeNameForTitleAndCmptDescrip & "_" & s row("QuanSharingConfiguration") = 1 row("QuanConfigured") = "0" 'This will be populated OnSave after user enters data 'TODO - f041Cyln - InsertCylnSensor - QuanActuations - 'Propagate this on to the sensors ~ is this really necessary row("QuanActuations") = _quanOfComponentActuations 'Propagate this on to the sensors 'TODO - f041Cyln - InsertCylnSensor - row("cmVarchar04") = "On" row("cmVarchar04") = "On" row("cmVarchar06") = _pkCmptIdOfParentForSensorAndParameter 'Give all other positions a FALSE value and only the proper position a TRUE value ' This allows proper filtering row("cmBit01") = False 'B row("cmBit02") = False 'D row("cmBit04") = False 'C row("cmBit05") = False 'A Select Case s Case "B" row("cmBit01") = True 'B Case "D" row("cmBit02") = True 'D Case "C" row("cmBit04") = True 'C Case "A" row("cmBit05") = True 'A End Select row("cmBit06") = True 'PNP NON row("cmBit07") = True 'is Motion sensor row("cmSmallint01") = 1 'Me.cboSensorVoltage.NSelectedValue ~ (1 = 24 volt) 'cmSmallint02 'cmSmallint03 'cmSmallint04 'cmSmallint05 row("cmSmallint06") = 5 'Me.cboSensorType.NSelectedValue ~ (5 = Hall effect) 'cmSmallint07 row("cmSmallint08") = 2 'Me.cboSensorConnection.NSelectedValue ~ (2 = Micro) row("cmUserNote") = "" row("cmCreatedOn") = Now.ToString row("cmCreatedBy") = SystemInformation.UserName.ToString row("cmEditedOn") = Now.ToString row("cmEditedBy") = SystemInformation.UserName.ToString ' The following data is entered by the user - later 'row("cmVarchar01") = ucase(Me.txtSensorIOAddress.Text) ' The following data is confirmed by the user - later 'row("cmBit06") = True 'PNP NON Catch ane As ArgumentNullException 'The exception that is thrown when a null reference (Nothing in Visual Basic) is passed to a method that does 'not accept it as a valid argument. Throw New DBAccessException("You are passing a 'Nothing' as a parameter to a method where an actual value is required.", ane) Catch ce As ConstraintException 'Represents the exception that is thrown when attempting an action that violates a constraint. Throw New DBAccessException("You have attempted an action that violates a constraint.", ce) Catch e As Exception 'Represents errors that occur during application execution. Throw New DBAccessException("An unanticipated exception has ocurred.", e) End Try Try _dataSet1.Tables(_currentTable).Rows.Add(row) '<<<This line causes the error Catch diee As Data.InvalidExpressionException 'Represents the exception that is thrown when attempting to add a DataColumn Throw New DBAccessException("The data column you are attempting to add contains an error.", diee) Catch dsee As SyntaxErrorException 'Represents the exception that is thrown when the Expression property of a DataColumn contains a syntax error. Throw New DBAccessException("The data column you are attempting to add contains a syntax error.", dsee) Catch e As Exception MessageBox.Show("Exception Message: " & vbCrLf & e.Message) MessageBox.Show("Exception Source: " & vbCrLf & e.Source) MessageBox.Show("Exception StackTrace: " & vbCrLf & e.StackTrace) 'Represents errors that occur during application execution. 'Throw New DBAccessException("An unanticipated exception has ocurred.", e) End Try End Sub // The error says ForeignKeyConstraint Lkp_tbl040Cmpt_lkp302SensorType requires the child key values (5) to exist in the parent table. The "5" is the value that is given to the field cmSmallint06 in the line shown here; \\ row("cmSmallint06") = 5 'Me.cboSensorType.NSelectedValue ~ (5 = Hall effect) // I don't understand why I am getting this error when I am passing the required value. Can someone explain what might be casusing this? (5 = Hall effect) Please help me. Thank you, dbuchanan Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121465
  - 20
    - Dtabinding and Update issues This is a multi-part message in MIME format. ------=_NextPart_000_0074_01C5F40F.2ADFBD40 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi All, I have a typed dataset which contains several tables. The 3 that I am = experiencing difficulty with are "CONTACTS", "ALL_ZIP_CODES" and = "E_ZIP_CODES." The "CONTACTS" table is selfexplantory. The table = "E_ZIP_CODES" is a subset of all ZIP codes that are in the "CONTACTS" = table. The table "ALL_ZIP_CODES" consists of a complete listing of ZIP = codes. What I am trying to do is, when a user updates or adds a new contact, I = search for the ZIP code in the "E_ZIP_CODES" table (dvSearch below). If = the ZIP code is not in the table "E_ZIP_CODES" (i =3D -1 below), I want = to add the ZIP code and city values from the "ALL_ZIP_CODES" datatable = to the datatable "E_ZIP_CODES" so that I can update the "CONTACTS" table = with the newly selected ZIP code. The new record is added to the = datatable and all appears to be fine. However, when I try to update the = "CONTACTS" datatable, I get the error "Failed to enable constraints" TIA, Vince ' Code to add new ZIP code Dim dv As New DataView Dim strSearch As String, i As Integer With dv .Table =3D dsMulti.Tables("ALL_ZIP_CODES") .Sort =3D "ZIP_CODE" .RowStateFilter =3D DataViewRowState.CurrentRows End With =20 strSearch =3D cboE_ZIP_Code.Text.ToString If strSearch =3D "" Then strSearch =3D txtE_ZIP_Code.Text.ToString Try Dim dvSearch As New DataView With dvSearch .Table =3D dsMulti.Tables("E_ZIP_CODES") .Sort =3D "ZIP_CODE" .RowStateFilter =3D DataViewRowState.CurrentRows End With i =3D dvSearch.Find(strSearch) If i =3D -1 Then Dim strCity As String With dv .Table =3D dsMulti.Tables("ALL_ZIP_CODES") .Sort =3D "ZIP_CODE" .RowStateFilter =3D DataViewRowState.CurrentRows End With i =3D dv.Find(strSearch) strCity =3D "Test" Dim rowNew As DataRow rowNew =3D dsMulti.Tables("E_ZIP_CODES").NewRow rowNew("ZIP_CODE") =3D strSearch rowNew("CITY") =3D strCity dsMulti.Tables("E_ZIP_CODES").NewRow.BeginEdit() dsMulti.Tables("E_ZIP_CODES").Rows.Add(rowNew) dsMulti.Tables("E_ZIP_CODES").AcceptChanges() End If Catch ex As Exception MsgBox(ex.Message.ToString) End Try ' Code to Update the CONTACTS table sbrContacts.Panels(4).Text =3D "Saving record ..." Try curContacts.Refresh() curContacts.EndCurrentEdit() ' Error here=20 With daContact.UpdateCommand .Parameters("I_F_NAME").Value =3D txtFName.Text .Parameters("I_M_NAME").Value =3D txtMI.Text .Parameters("I_L_NAME").Value =3D txtLName.Text .Parameters("I_CAOID").Value =3D cboCAO.ValueMember .Parameters("I_LEVELID").Value =3D cboLevel.ValueMember .Parameters("I_COMPANYID").Value =3D = cboCompany.ValueMember .Parameters("I_SITEID").Value =3D cboSite.ValueMember .Parameters("I_SUB_TEAMID").Value =3D = cboSubTeam.ValueMember .Parameters("I_FUNCTIONID").Value =3D = cboFunction.ValueMember .Parameters("I_SUB_FUNCTIONID").Value =3D = cboSubTeam_Function.ValueMember .Parameters("I_SUB_FUNCTION_2_ID").Value =3D = cboSubTeam_Function_2.ValueMember .Parameters("I_POSITIONID").Value =3D = cboPosition.ValueMember .Parameters("I_BUS_PHONE").Value =3D txtBus_Phone.Text .Parameters("I_BUS_PHONE_2").Value =3D = txtBus_Phone_2.Text .Parameters("I_BUS_MOBILE").Value =3D txtBus_Mobile.Text .Parameters("I_BUS_OTHER").Value =3D txtBus_Other.Text .Parameters("I_BUS_FAX").Value =3D txtBus_Fax.Text .Parameters("I_BUS_FAX_2").Value =3D txtBus_Fax_2.Text .Parameters("I_BUS_PAGER").Value =3D txtBus_Pager.Text .Parameters("I_BUS_EMAIL").Value =3D txtBus_eMail.Text .Parameters("I_NOTES").Value =3D txtNotes.Text .Parameters("I_SSN").Value =3D txtSSN.Text .Parameters("I_PAYROLL_NUM").Value =3D = txtPayroll_Num.Text .Parameters("I_GS_SERIES").Value =3D txtGS_Series.Text .Parameters("I_GS_GRADE").Value =3D txtGS_Grade.Text .Parameters("I_H_STREET_1").Value =3D txtH_Street_1.Text .Parameters("I_H_STREET_2").Value =3D txtH_Street_2.Text .Parameters("I_H_ZIP_CODE").Value =3D cboH_ZIP_Code.Text .Parameters("I_H_PHONE").Value =3D txtH_Phone.Text .Parameters("I_H_PHONE_2").Value =3D txtH_Phone_2.Text .Parameters("I_H_MOBILE").Value =3D txtH_Mobile.Text .Parameters("I_H_MOBILE_2").Value =3D txtH_Mobile_2.Text .Parameters("I_H_PAGER").Value =3D txtH_Pager.Text .Parameters("I_H_FAX").Value =3D txtH_Fax.Text .Parameters("I_H_EMAIL").Value =3D txtH_eMail.Text .Parameters("I_E_CONTACT").Value =3D txtE_Contact.Text .Parameters("I_E_STREET").Value =3D txtE_Street.Text .Parameters("I_E_STREET_2").Value =3D txtE_Street_2.Text .Parameters("I_E_ZIP_CODE").Value =3D cboE_ZIP_Code.Text .Parameters("I_E_PHONE").Value =3D txtE_Phone.Text .Parameters("I_E_PHONE_2").Value =3D txtE_Phone_2.Text .Parameters("I_E_PHONE_3").Value =3D txtE_Phone_3.Text .Parameters("I_CONTACTID").Value =3D lblContactID.Text End With daContact.Update(dsMulti, "CONTACTS") daContact.Fill(dsMulti, "CONTACTS") sbrContacts.Panels(4).Text =3D "Ready" Cursor.Current =3D System.Windows.Forms.Cursors.Default Catch oraEX As OracleException sbrContacts.Panels(4).Text =3D "Error" Cursor.Current =3D System.Windows.Forms.Cursors.Default MsgBox(oraEX.Message.ToString) End Try ------=_NextPart_000_0074_01C5F40F.2ADFBD40 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=3DContent-Type content=3D"text/html; = charset=3Diso-8859-1"> <META content=3D"MSHTML 6.00.2900.2769" name=3DGENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=3D#ffffff> <DIV><FONT face=3DArial size=3D2>Hi All,</FONT></DIV> <DIV> </DIV> <DIV><FONT face=3DArial size=3D2>I have a typed dataset which contains = several=20 tables. The 3 that I am experiencing difficulty with are "CONTACTS",=20 "ALL_ZIP_CODES" and "E_ZIP_CODES." The "CONTACTS" table is = selfexplantory. The=20 table "E_ZIP_CODES" is a subset of all ZIP codes that are in the = "CONTACTS"=20 table. The table "ALL_ZIP_CODES" consists of a complete listing of ZIP=20 codes.</FONT></DIV> <DIV> </DIV> <DIV><FONT face=3DArial size=3D2>What I am trying to do is, when a user = updates or=20 adds a new contact, I search for the ZIP code in the "E_ZIP_CODES" table = (dvSearch below). If the ZIP code is not in the table "E_ZIP_CODES" (i = =3D -1=20 below), I want to add the ZIP code and city values from the = "ALL_ZIP_CODES"=20 datatable to the datatable "E_ZIP_CODES" so that I can update the = "CONTACTS"=20 table with the newly selected ZIP code. The new record is added to the = datatable=20 and all appears to be fine. However, when I try to update the "CONTACTS" = datatable, I get the error "Failed to enable constraints"</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>TIA,</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>Vince</FONT></DIV> <DIV> </DIV> <DIV><FONT face=3DArial size=3D2>' Code to add new ZIP code<BR>Dim dv As = New=20 DataView<BR>Dim strSearch As String, i As Integer</FONT></DIV> <DIV> </DIV> <DIV><FONT face=3DArial size=3D2>With dv<BR> .Table =3D=20 dsMulti.Tables("ALL_ZIP_CODES")<BR> .Sort =3D=20 "ZIP_CODE"<BR> .RowStateFilter =3D = DataViewRowState.CurrentRows<BR>End=20 With<BR>        <BR>strSearch =3D=20 cboE_ZIP_Code.Text.ToString</FONT></DIV> <DIV> </DIV> <DIV><FONT face=3DArial size=3D2>If strSearch =3D "" Then strSearch =3D=20 txtE_ZIP_Code.Text.ToString</FONT></DIV> <DIV> </DIV> <DIV><FONT face=3DArial size=3D2>Try<BR> Dim dvSearch As New=20 DataView<BR> With dvSearch<BR>  .Table =3D=20 dsMulti.Tables("E_ZIP_CODES")<BR>      &nbs= p;        =20 .Sort =3D=20 "ZIP_CODE"<BR>         &nbsp= ;     =20 .RowStateFilter =3D DataViewRowState.CurrentRows<BR> End = With<BR> i =3D=20 dvSearch.Find(strSearch)<BR> If i =3D -1 Then<BR>    = Dim=20 strCity As String<BR>    With dv<BR>   =20     .Table =3D=20 dsMulti.Tables("ALL_ZIP_CODES")<BR>        = .Sort =3D=20 "ZIP_CODE"<BR>        .RowStateFilter =3D=20 DataViewRowState.CurrentRows<BR>    End=20 With<BR>    i =3D = dv.Find(strSearch)<BR>    strCity=20 =3D "Test"<BR>    Dim rowNew As = DataRow<BR>   =20 rowNew =3D dsMulti.Tables("E_ZIP_CODES").NewRow<BR>   =20 rowNew("ZIP_CODE") =3D strSearch<BR>    rowNew("CITY") = =3D=20 strCity<BR>   =20 dsMulti.Tables("E_ZIP_CODES").NewRow.BeginEdit()<BR>   =20 dsMulti.Tables("E_ZIP_CODES").Rows.Add(rowNew)<BR>   =20 dsMulti.Tables("E_ZIP_CODES").AcceptChanges()<BR>End If<BR>Catch ex As=20 Exception<BR> MsgBox(ex.Message.ToString)<BR>End Try</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>' Code to Update the CONTACTS=20 table<BR>       sbrContacts.Panels(4).Text = =3D=20 "Saving record ..."<BR>Try<BR> curContacts.Refresh()<BR><FONT=20 color=3D#ff0000> curContacts.EndCurrentEdit() ' Error=20 here </FONT><BR> With=20 daContact.UpdateCommand<BR>       &nbs= p;        .Parameters("I_F_NAME")= .Value=20 =3D=20 txtFName.Text<BR>         &n= bsp;     =20 .Parameters("I_M_NAME").Value =3D=20 txtMI.Text<BR>         &nbsp= ;     =20 .Parameters("I_L_NAME").Value =3D=20 txtLName.Text<BR>         &n= bsp;     =20 .Parameters("I_CAOID").Value =3D=20 cboCAO.ValueMember<BR>        &nb= sp;      =20 .Parameters("I_LEVELID").Value =3D=20 cboLevel.ValueMember<BR>        &= nbsp;      =20 .Parameters("I_COMPANYID").Value =3D=20 cboCompany.ValueMember<BR>       &nbsp= ;       =20 .Parameters("I_SITEID").Value =3D=20 cboSite.ValueMember<BR>        &n= bsp;      =20 .Parameters("I_SUB_TEAMID").Value =3D=20 cboSubTeam.ValueMember<BR>       &nbsp= ;       =20 .Parameters("I_FUNCTIONID").Value =3D=20 cboFunction.ValueMember<BR>       &nbs= p;       =20 .Parameters("I_SUB_FUNCTIONID").Value =3D=20 cboSubTeam_Function.ValueMember<BR>      &n= bsp;        =20 .Parameters("I_SUB_FUNCTION_2_ID").Value =3D=20 cboSubTeam_Function_2.ValueMember<BR>      =          =20 .Parameters("I_POSITIONID").Value =3D=20 cboPosition.ValueMember<BR>       &nbs= p;       =20 .Parameters("I_BUS_PHONE").Value =3D=20 txtBus_Phone.Text<BR>        &nbs= p;      =20 .Parameters("I_BUS_PHONE_2").Value =3D=20 txtBus_Phone_2.Text<BR>        &n= bsp;      =20 .Parameters("I_BUS_MOBILE").Value =3D=20 txtBus_Mobile.Text<BR>        &nb= sp;      =20 .Parameters("I_BUS_OTHER").Value =3D=20 txtBus_Other.Text<BR>        &nbs= p;      =20 .Parameters("I_BUS_FAX").Value =3D=20 txtBus_Fax.Text<BR>         =       =20 .Parameters("I_BUS_FAX_2").Value =3D=20 txtBus_Fax_2.Text<BR>        &nbs= p;      =20 .Parameters("I_BUS_PAGER").Value =3D=20 txtBus_Pager.Text<BR>        &nbs= p;      =20 .Parameters("I_BUS_EMAIL").Value =3D=20 txtBus_eMail.Text<BR>        &nbs= p;      =20 .Parameters("I_NOTES").Value =3D=20 txtNotes.Text<BR>         &n= bsp;     =20 .Parameters("I_SSN").Value =3D=20 txtSSN.Text<BR>         &nbs= p;     =20 .Parameters("I_PAYROLL_NUM").Value =3D=20 txtPayroll_Num.Text<BR>        &n= bsp;      =20 .Parameters("I_GS_SERIES").Value =3D=20 txtGS_Series.Text<BR>        &nbs= p;      =20 .Parameters("I_GS_GRADE").Value =3D=20 txtGS_Grade.Text<BR>        &nbsp= ;      =20 .Parameters("I_H_STREET_1").Value =3D=20 txtH_Street_1.Text<BR>        &nb= sp;      =20 .Parameters("I_H_STREET_2").Value =3D=20 txtH_Street_2.Text<BR>        &nb= sp;      =20 .Parameters("I_H_ZIP_CODE").Value =3D=20 cboH_ZIP_Code.Text<BR>        &nb= sp;      =20 .Parameters("I_H_PHONE").Value =3D=20 txtH_Phone.Text<BR>         =       =20 .Parameters("I_H_PHONE_2").Value =3D=20 txtH_Phone_2.Text<BR>        &nbs= p;      =20 .Parameters("I_H_MOBILE").Value =3D=20 txtH_Mobile.Text<BR>        &nbsp= ;      =20 .Parameters("I_H_MOBILE_2").Value =3D=20 txtH_Mobile_2.Text<BR>        &nb= sp;      =20 .Parameters("I_H_PAGER").Value =3D=20 txtH_Pager.Text<BR>         =       =20 .Parameters("I_H_FAX").Value =3D=20 txtH_Fax.Text<BR>         &n= bsp;     =20 .Parameters("I_H_EMAIL").Value =3D=20 txtH_eMail.Text<BR>         =       =20 .Parameters("I_E_CONTACT").Value =3D=20 txtE_Contact.Text<BR>        &nbs= p;      =20 .Parameters("I_E_STREET").Value =3D=20 txtE_Street.Text<BR>        &nbsp= ;      =20 .Parameters("I_E_STREET_2").Value =3D=20 txtE_Street_2.Text<BR>        &nb= sp;      =20 .Parameters("I_E_ZIP_CODE").Value =3D=20 cboE_ZIP_Code.Text<BR>        &nb= sp;      =20 .Parameters("I_E_PHONE").Value =3D=20 txtE_Phone.Text<BR>         =       =20 .Parameters("I_E_PHONE_2").Value =3D=20 txtE_Phone_2.Text<BR>        &nbs= p;      =20 .Parameters("I_E_PHONE_3").Value =3D=20 txtE_Phone_3.Text<BR>        &nbs= p;      =20 .Parameters("I_CONTACTID").Value =3D=20 lblContactID.Text<BR>        &nbs= p;  =20 End = With<BR>          &nbsp= ;=20 daContact.Update(dsMulti,=20 "CONTACTS")<BR>         &nbs= p; =20 daContact.Fill(dsMulti,=20 "CONTACTS")<BR>         &nbs= p; =20 sbrContacts.Panels(4).Text =3D=20 "Ready"<BR>          &n= bsp;=20 Cursor.Current =3D System.Windows.Forms.Cursors.Default<BR>Catch oraEX = As=20 OracleException<BR> sbrContacts.Panels(4).Text =3D=20 "Error"<BR> Cursor.Current =3D=20 System.Windows.Forms.Cursors.Default<BR> MsgBox(oraEX.Message.ToStri= ng)<BR>End=20 Try<BR></FONT></DIV></BODY></HTML> ------=_NextPart_000_0074_01C5F40F.2ADFBD40-- Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121460
  - 21
    - ANN: OleDBProNet for .NET version 2 is released at www.udaparts.com Hi, All: OleDBProNet is a .NET class library which is a complete, feature-rich, and extremely powerful data access solution for .NET programmers through MS OLEDB technology. It offers the following key benefits over ADO.NET: 1. Extremely simple: OleDBProNet hides all of complexities of raw OLEDB programming. It is written with the classical ADO data accessing model. You will never meet BLOBs and other complicate data types conversion to bother you for all types of SQL statements. OleDBProNet comes with fifteen real and advanced C# and VB.NET samples to assist your developments no matter what programming background you have. If you have somewhat background in old ADO (Active Data Objects), you will feel OleDBProNet is extremely simple and intuitive to use. 2. Many features available: OleDBProNet supports all types of client and server cursors as shown in the attached samples. It supports all of advanced rowset navigation features (bookmark, record searching, index, bi-directional scrolling and jumping etc) directly on server side. OleDBProNet offers much more features than ADO.NET. 3. Super performance: OleDBProNet is written from Visual C++ 2005 C++/CLI with direct use of raw OLEDB interfaces, which almost eliminates data marshaling across layers between native and managed codes completely. Also, OleDBPro uses batching mode (20 records per batch) to retrieve and update records by default. Generally, OleDBProNet is about five times as fast as ADO in .NET environment. Also, OleDBProNet is about 15% faster than MS OleDB.NET provider. OleDBProNet can manage huge data records using server cursors, but ADO.NET can't. Therefore, OleDBProNet is significantly faster and simpler than ADO.NET for accessing a large number of data records. 4. Complete solution to all types of your databases: OleDBProNet is a complete solution to all of types of databases, SQL server, Oracle, Access, MySQL, DB2, ....... As long as you have an OLEDB provider, or ODBC driver, or ISAM driver available, it will work for you with one copy of code. -- Yuancai (Charlie) Ye Fast accessing all of remote data sources anywhere with SocketPro using batch/queue, non-blocking and parallel computation See 30 well-tested and real OLEDB examples at http://www.udaparts.com Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121458
  - 22
    - Comparing two datasets I need to compare the values of two datasets and retrieve the differences into a third dataset. I need to retrieve Employees names and numbers from Excel sheet into ds1 and retrieve Employees names and numbers from SQL Employees Table into ds2. I did this part successfully. Now i want to compare the values of both datasets so I can figure out new added employees in the Excel sheet and add them into ds3. How can I do that? I know i need to loop through one and look for each record in the other but I can't get the idea ... can anyone give me a sample of how to do this? Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121445
  - 23
    - best practice for transactions Hi, I'am developing an asp.net app that is using an sql server. How should I deal with transactions? Should I do the transactions in my stored procedures or should I use Serviced Components or... Thanks Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121443
  - 24
    - That pesky timestamp thing Creating a datatable from scratch and then I'm inserting with a select in the sproc to return the current values after the insert. Now I realize the timestamp column is a datatype of byte, and I'm not trying to insert the timestamp, but I want to keep the column in the datatable to be populated with the return values. However, when the dataadapter tries to apply the update, I'm getting an exception on the datatable timestamp datatype. Any thoughts? Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121440
  - 25
    - Getting the value of an identity column after an insert Hi all. I am trying to resolve this seemingly very simple and not to mention well documented problem but just couldn't seem to get it to work. I have a datatable that uses an identity column as the primary key. I need to get the value of the identity column back after performing an insert to the SQL Server 2005 (beta) database. From all the information that I have gathered, the following code should work: 1 SqlConnection conn = new SqlConnection(connStr); 2 conn.Open(); 3 SqlCommand cmd = new SqlCommand(string.Format("SELECT * FROM {0}", dt.TableName), conn); 4 SqlDataAdapter da = new SqlDataAdapter(cmd); 5 SqlCommandBuilder CB = new SqlCommandBuilder(da); 6 da.InsertCommand = CB.GetInsertCommand(); 7 da.InsertCommand.CommandText += string.Format("; SELECT * FROM {0} WHERE {1} = @@IDENTITY", dt.TableName, "PKeyID"); 8 da.InsertCommand.UpdatedRowSource = UpdateRowSource.Both; 9 da.Update(dt); 10 dt.AcceptChanges(); * dt is the database containing the rows that need to be inserted. * I had the FillSchema operated on dt so the identity column's AutoIncrement property is set to true. * I set the AutoIncrementSeed and AutoIncrementStep properties of the identity column set to -1. * I have already tried setting the UpdatedRowSource property to "Both" and "FirstReturnedRecord". But after running the above code, the value of the identity column remains -1. What am I missing??? In addition, if I need to wrap the update within a transaction, should I invoke the AcceptChanges call inside or outside the transaction? Will the row state reverse along with a rollback call? Any help will be greatly appreciated. Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121436
- Next
  - 1
    - Visual design tools and DAL in VS 2005 / .NET 2.0 Hi I wrote quite a few apps with .NET 1.0 and 1.1, which made use of a Data Access Layer, and also used the Microsoft Application Blocks for Data Access (v2). In VS 2005, there is a huge improvement in 'visually' designing the data access, and binding it to the controls on the form. I have 'played around' with the SqlDataSource component, which allows very quick, easy and simple access to a SQL DB. However, I have a couple of considerations, which I would like to get opinions on.... 1). If I want to use a common ConnectionString (ie. just have it coded in one place), how can I bind each of my controls to this connection?? (ie. I don't want to change 100's of controls if my connection string changes). 2). I want to keep in mind the 'Enterprise' way of doing things, via a DAL or Business Layer. Does anyone have any good source (C#), which shows the implementation of a Front end, DAL, and the component bindings. This can be using SQL commands, or Stored procedures, but I would appreciate details of Updates / Inserts etc, as well as simple selects (so that I can see the impact on Table Adapters etc). Thanks in advance Paul Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121435
  - 2
    - Conditions of DataBinding what are the conditions in order to bind to an object? i have an object, which implements the IList interface. Now I'am able to bind the objects, which are hold by the collection. now i implemented two properties in my collection. but i'm not able to bind to the properties of the collection itself. it must be the object in the list. that are my experiences. Example: public class MyCollection : IList { //Implementations of IList and so on.. public event EventHandler myValueChanged; public int myValue { get { return iMyValue; } set { iMyValue = value; if(myValueChanged != null) myValueChanged(this, EventArgs.Empty); } } } And i try to bind to an object.. //That works... textBox1.DataBindings.Add("Text", myClassInstance[1], "ValueOfMyObjectInList"); //That doesn't work numericBox1.DataBindings.Add("Value", myClassInstance, "myValue"); I get an error which tells me, that he isn't able to bind to a property or column of the datasource. parameter name: dataMember is it possible to bind to a property of a collection itself? Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121433
  - 3
    - Paging Problem I've got a PageIndexChanged event handler as follows: Private Sub dg_PageIndexChanged (ByVal s as System.Object, ByVal e As System.DataGridPageIndexChangedEventArgs) Handles dg.PageIndexChanged dg.CurrentPageIndex = e.NewPageIndex dg.DataSource = ds.Tables("ABC") dg.DataBind( ) End Sub ___________________________________ The datagrid does not display the next 10 rows of data when I clicked on the page number. As I have a dropdownlist, I selected another item and then back to the same item sgain. This time, when I clicked on the new page number, the next 10 rows were displayed. This is not what I want. It should be that when a new page number is selected, the next 10 rows will be displayed immediately. Don't know what's the problem. Can anyone help ? Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121430
  - 4
    - Losing Dataset icon/instance from project I've got a project with a Typed Dataset. The dataset consists of several tables. Every time I attempt to go into the dataset to adjust a table, like adding a new column that was added to the DB, I lose the dataset's icon in the designer and when I look in the project code the line of code where it get's dim'd is missing. I then have to go through a convoluted mess of tweaking to get the dataset back into the project. The XSD & dataset designer always stay intact, but I lose the Dataset from the project it was being used in. This is a VB.NET project in VS.NET 2003. I've had this happen in another project as well. So, I have to assume its a known bug, but I haven't been able to find any refrence to it on MSDN or Google. Any help on how to circumvent this issue would be greatly appreciated. I lose several hours everytime I have to modify the dataset... and when I have to modify the dataset again I've forgotten what the heck it was I did to get it working again the previous time! Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121429
  - 5
    - Insert BLOB problem Hi all, I am trying to use System.Data.ODBC to insert a file into a binary field in SQL Server 2000. Now, before you yell at me, the reason I am doing this is that I am only writing intitial code against SQL, but this app will need to be able to run against any ODBC compliant DB, so I am also not using stored procedures. I have tangles with this for hours, but I cannot seem to figure out how to just read the contents of a file off disk and write it into a binary field in SQL not using a stored procedure. If I can get that working, I can do whatever I need, but I can't so far. Does anyone have a sample of this or an article? There are many articles for doing this with SPROCS, doing this with SqlClient, not ODBC. I tried just modifying the objects from an SqlClient example, but no avail. Appreciate any help on this... Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121422
  - 6
    - Problem updating object behind bindingSource Hi folks, I have an form where there are two text boxes bound to an object via a BindingSource. I have implemented a document save function via Binary Serialization that writes the underlying object to disk. The problem is, if a user edits the data in one of the text boxes but DOES NOT leave the text box before selecting the Save menu item, the change in the text box is not replicated back to the object behind the form (the object that is serialized). Hence when I reload the document the Deserialized data contains the contents of the textbox before the user changed it. If the user leaves the textbox first, everything is fine. My thinking is that I need to force the form to propagate its current state back to the object before serializing, but would take some advice on the best way to do this. I appreciate this is not strictly an ADO.NET question but figured that being a data binding issue, someone on here might be able to help. Many thanks in advance. Simon Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121419
  - 7
    - VB.NET and MYSQL 5.0, Character Set Problem I am writing and VB.NET application, connect to MYSQL 5.0 (Linux) using MysqlConnector.NET The problem is it can't display and update correct Chinese Character. What Can I do? Thank you Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121414
  - 8
    - BindingSource.Clear method Hiya, I'm mucking around with .net 2, and experimenting with the BindingSource control. I've set the datasource to a dataset and set the datamember property as the table (or perhaps i've directly set the datasource to the table and left the datamember as null). When I run the Clear() method on the BindingSource, I get an exception from the runtime saying that the clear method cannot be used on the underlying datasource. Any ideas what I'm doign wrong? Thanks Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121409
  - 9
    - MSDN I just installed MSDN on my local computer. I set it up using 'BLANKSAPWD=1, and INSTANCENAME=kennel'. I attached my database using 'oSQL -E -S icc-station\kennel' utility. That went well. My original testing is with SqlServer 2000. and that was fine. The problem that I am having is I get the message 'SQL Server does not exist or access denied' My connecting string follows: this.cnKennel.ConnectionString = "Data Source=(local)\\kennel" + ";initial catalog=kennel" + ";Trusted_Connection=Yes" + ";integrated security=SSPI" + ";Connect Timeout=5"; Please tell me what I doing wrong??? -- Norm Bohana Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121408
  - 10
    - Hiding columns in a data grid (.net, c#) I wish to display, in a datagrid, only six columns of a table containing about twenty. I've created a data adapter which selects only the desired columns. I created a dataset and a dataview, and specified the dataview as the data source for my datagrid. The datagrid displays the 6 desired columns, in the sequence that I selected them, followed by the remaning 14. I read someplace that this is the default behavior. Two questions: (1) How do I hide the unwanted 14 coulumns? (2) How can I change the column headings to something other than the column name of the underlying table? Thanks, Phil raincounty<*>hotmail.com -- replace the <*> with you know what Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121407
  - 11
    - DataBinding problem Hello, i written a collection which holds instances of a specifc class. i added a binding like that textBox1.DataBindings.Add("Text", ((MyClass)oMyCollection[1], "Description"); If the content of the textbox changed, the values are saved in the object of the collection where the controls is bound to. my problem is that other controls don't refresh their data. so if i change the value of a property in my instance. the control still holds the old value. i tried the following: this.BindingContext[((MyClass)oMyCollection[1], "Description"].EndCurrentEdit(); but it wasn't the solution. any ideas? Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121401
  - 12
    - Debugging SQL Server 200 Stored Procedures with ADO .NET With SQL Server 2000 with SP3a we used to be able to debug our Stored Procedures by stepping into them via our ADO .NET code, but we have recently upgraded to SP4 and can no longer do this unless we connect as 'sa'. We have made sue that the Extended Stored Procedure sp_sdidebug can be accessed by the user we normally connect as and we always execute the following line on startup to turn on legacy debugging. exec [master].[dbo].[sp_sdidebug] 'legacy_on' Furthermore we have verified in our DCOM configuration properties that under 'Default Protocols' there is a 'Connection-orientated TCP/IP' entry and this is the first entry in the list. Any help on why we are unable to debug our stored procedures would be greatfully appreciated. Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121394
  - 13
    - typed dataset + null values + cm.EndCurrentEdit Hi, I have a typed ds which contains a single table which in turn has a number of columns for which "min occurs = 0". The columns from this ds are bound to a bunch of controls on a form. I am having some trouble with the currencymanager when it comes to adding a new row, as follows; 1. Addnew method called 2. User starts entering data 3. User decides to exit form using control box (X) upper right then; Validating event for non nullable control fires and sets cancel to true Form Closing event fires and attempts to catch changes to ds using the EndCurrentEdit in order to allow user the option to stop. EndCurrentEdit causes "System.Data.NoNullAllowedException, "Column 'PS_PhoneNumber' does not allow nulls." Problem: if I don't call EndCurrentEdit the ds.HasChanges is False. If I do, I get the above exception. I thought I should be able to end the edit and check the ds.HasErrors rather than have the exception generated. I suspect I don't understand something here. Any advice would be appreciated. Thanks Paul Sample: (Hopefull enough1) Private Sub ubtnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ubtnAdd.Click ' Add new patient record. cmPatients.EndCurrentEdit() cmPatients.AddNew() End Sub Private Sub unePhone_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles unePhone.Validating If unePhone.Value Is System.DBNull.Value Then Me.epPatients.SetError(unePhone, "Phone Number Must Be Entered") e.Cancel = True Else Me.epPatients.SetError(unePhone, "") End If End Sub Private Sub frmMaintPatients_Closing(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing ' Check there are no outstanding changes which have not been sent to the DB cmPatients.EndCurrentEdit() ''''' PROBLEM HERE!! If dsMaintPatients.HasChanges Then If Not DiscardUserChanges() Then e.Cancel = True Exit Sub End If End If ' Allow the form to close even if the user has become stuck in validating events e.Cancel = False End Sub Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121392
  - 14
    - Embeded MySQL with C# I wrote an application using c# and mySQL database. But when I deploy it doesn't work on an other PC. How can I embed mysql in C#. A code example will be quite helpful for me. Any help wll be appreciated. Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121390
  - 15
    - Retrieving untyped dataset schema What's the best approach to retrieving schema for an untyped dataset? Do it manually, an empty sproc, what else? Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121389
  - 16
    - Click on hyperlink column to launch audio clips I have a datagrid that consists of a data-bound hyperlink column binded to the "Song Name" column of the data source. When user clicks on one of the links, the associated media application such as RealPlayer or Windows Media Player will be launched. I searched through the MSDN Library and found that Windows API can be used to play simple sounds. Is there other alternatives to achieve it ? Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121387
  - 17
    - is it possible to use ip:port instead of sid for oracleconnection? for example: connectionstr="DATA SOURCE=192.168.1.11:1521;UID=bnd;PWD=bnd;" instead of connectionstr="DATA SOURCE=sid;UID=bnd;PWD=bnd;" new oracleconnection(connectionstr); is it ok, and what is the format of data source? Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121384
  - 18
    - Query Builder Tool Is there out a Query Builder Tool that is possible to integrate into my application ? Mainly for MS SQL Server. Which one do you recommend ? Thanks in advance Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121379
  - 19
    - This has to be a BUG After spending a few hours experimenting the typed dataset serialization (see previous post "How to include public properties in a typed dataset in serialization"), this is what I found which does look like a bug (I'm using the normal serialization with XmlSerializer): . The values for the public property are in fact written into the Xml. They are presented as the attributes of the Element for the Dataset. They have the namespace of "msdata". . If the public property is of Int16, it will be ignored and not written into the Xml. . For the public properties which are written into the Xml, the deserialization does not recover them. This means that the instance returned from the deserialization doesn't have these property values set. So it seems to me that something is only half done here. If the behaviour is by design, then I don't understand why these public properties were written into the Xml in the first place. And why properties with certain data type are not written into the Xml at the same time. Michael Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121378
  - 20
    - Data->Generate Dataset|Preview Data I am writing an ADO.NET provider for a specialized (non-SQL) data store, and wanted to support the options in the Data menu, specifically "Generate Dataset" and "Preview Data". The documentation on these types of features is near to non-existant, including when you download the VSIP package (I thought that would help but it doesn't). I have the following three problems: 1. I cannot get my DataAdapter implementation to enable these menu options. 2. If I add another adapter, which does enable these options, the Generate Dataset option gives me a dialog box titled "Microsoft Development Environment" with the following text in it: "Retrieving the schema for MyDataAdapter1 failed. Object reference not set to an instance of an object." 3. Also, with another adapter to enable these options, if you select my adapter in the Preview Data dialog, and attempt to "Fill Dataset", you get the following error message in another "Microsoft Development Environment" dialog box: "The data adapter "MyDataAdapter1" is not completely configured. To resolve this problem, configure the adapter by using the Data Adapter Configuration Wizard or by setting the SelectCommand property of the adapter." My question is this. Is there any place that defines what these option expect, or what calls they make to a DataAdapter implementation? Any place where this is documented in a useful fashion. The documentation for all of this is really sparse!!! Help! ;) Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121375
  - 21
    - Error converting data type numeric to decimal? I am running a stored procedure and getting the error 'Error converting data type numeric to decimal'. I just can't work out why. My stored procedure values are defined like so: @addOn1 decimal(7,2), @addOn2 decimal(7,2), @addOn3 decimal(7,2), @addOn4 decimal(7,2), @addOn5 decimal(7,2), @addOn6 decimal(7,2), @addOn7 decimal(7,2), @addOn8 decimal(7,2) These map to the precision/scale values in my database. I am calling the stored procedure from dotnet like so: sqlCmd.Parameters.Add("addOn1", objPremium.addOn1); sqlCmd.Parameters.Add("addOn2", objPremium.addOn2); sqlCmd.Parameters.Add("addOn3", objPremium.addOn3); sqlCmd.Parameters.Add("addOn4", objPremium.addOn4); sqlCmd.Parameters.Add("addOn5", objPremium.addOn5); sqlCmd.Parameters.Add("addOn6", objPremium.addOn6); sqlCmd.Parameters.Add("addOn7", objPremium.addOn7); sqlCmd.Parameters.Add("addOn8", objPremium.addOn8); try { sqlCmd.ExecuteNonQuery(); blnReturnVal = true; } catch(Exception e) { Debug.Trace.WriteLine(e); blnReturnVal = false; } And getting the exception there. the objPremium.addOn1 - objPremium.addOn8 values are all decimals. I am instantiating them like so and not setting them to anything else (for debug purposes): public decimal addOn1 = -1; public decimal addOn2 = -1; public decimal addOn3 = -1; public decimal addOn4 = -1; public decimal addOn5 = -1; public decimal addOn6 = -1; public decimal addOn7 = -1; public decimal addOn8 = -1; I'm sure it's something obvious, but can anybody spot what I'm doing wrong? Thanks in advance! Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121370
  - 22
    - MS Access problems Hi there, I'm currently rewriting an old VB 6 (stand alone) application in VB .Net 2003 in which users can create MS Access databases. In the new version I want to add security options like encrypting the database, adding users and groups etc. I managed to create MS access databases and tables using ADOX, but I can't add users and groups to it. I use the following code: Dim myCat as New ADOX.Catalog Dim myCon as OleDb.OleDbConnection Dim myConStr as String Dim myNewUser as ADOX.User Dim myNewGroup as ADOX.Group Try myConStr = "Provider=Microsoft.Jet.OLEDB.4.0; Jet oledb:system database=system.mdw;" & _ "Data Source=C:\Test.mdb" 'Creating the database myCat.Create(myConStr) myCon = New OleDb.OleDbConnection(myConStr) myCon.Open() myCat.ActiveConnection = myCon <<-- This seems to be the problem after debugging the code 'Creating a new group myCat.Groups.Append("User group") 'Creating a new user myNewUser = New ADOX.User myNewUser.Name = "Jan Janssen" myCat.Users.Append(myNewUser) 'Add new user to the new group myNewUser.Groups.Append("User Group") myCon.Close() myCat = Nothing myCon = Nothing Catch ex as Exception MessageBox.Show(ex.Message) End Try When executing this code the following error occurs: "Interface not supported" Can anyone help me out or is there an alternative approach without using SQL servers? thnx Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121369
  - 23
    - Convert is not a member of String Hi All, I have the following Code: Public Sub SetAccessLevelNull() Me(Me.tableGeneralPasswords.AccessLevelColumn) = System.Convert.DBNull End Sub Im getting a ErroR on this Saying "Convert is Not a Member of String" Could somebody kindly point me in the right direct? Many Thanks NSC Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121366
  - 24
    - Convert is not a member of String Hi All, I have the following Code: Public Sub SetAccessLevelNull() Me(Me.tableGeneralPasswords.AccessLevelColumn) = System.Convert.DBNull End Sub Im getting a ErroR on this Saying "Convert is Not a Member of String" Could somebody kindly point me in the right direct? Many Thanks NSC Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121365
  - 25
    - Cannot add integer or long column to microsoft access table using ado.net Hi, I have a problem. I can't add integer or long columns to ms access table using ado.net. Could you just take a look at it. I think sql syntax is correct. The weird thing is that in another program it is working and it is the same code. If you comment out these two lines of code: "IDParent INTEGER, "+ "Position INTEGER, "+ then everything is ok, the table is created. The problem is I can't add LONG or INTEGER columns. I don't know what's going on, maybe it's some kind of a bug? Sample usage: Test.exe c:\\test.mdb using System; using System.Data; using System.Data.OleDb; namespace Test { public class Test { /// <summary> /// The main entry point for the application. /// </summary> [STAThread] static void Main(string[] args) { Test t = new Test(); if (args.Length ==1) { t.Execute(args[0]); } } private string connectionString = ""; private OleDbConnection connection; private bool CreateTableWorkTopics() { string sqlText = "CREATE TABLE WorkTopics "+ "(IDWorkTopic COUNTER, "+ "IDParent INTEGER, "+ "Position INTEGER, "+ "Title CHAR(255), "+ "CONSTRAINT WorkTopics_PK PRIMARY KEY (IDWorkTopic))"; ExecuteNonQuery(sqlText); return true; } private void ExecuteNonQuery(string sqlText) { OleDbCommand cmd = new OleDbCommand(sqlText, connection); cmd.CommandType = CommandType.Text; cmd.ExecuteNonQuery(); } public void Execute(string path) { try { connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;"+ "Data Source=\""+path+"\";"+ "User ID=Admin;"+ "Password="; // create mdb file if (!System.IO.File.Exists(path)) { ADOX.CatalogClass catalog = new ADOX.CatalogClass(); catalog.Create(connectionString); catalog = null; } connection = new OleDbConnection(connectionString); connection.Open(); CreateTableWorkTopics(); connection.Close(); } catch (Exception ex) { Console.WriteLine(ex.ToString()); Console.ReadLine(); } } } } Tag: Data Access and Middle-Tier... Control Library or Web Services Tag: 121362

Does anybody have strategies on when to through your Data Access and
Middle-Tier into a Web Service opposed to a Control Library?

I mostly deal with intranet ASP.NET web applications, and occasionally
create web services that access my Data Access (which is in a control
library). Right now my data access passes back datasets, datareaders,
or XML. I know passing datasets and datareaders over web services can
be pretty expensive.

I have talked to a number of people who put everything in web services,
but I don't see the advantage if it is an internal application. Is
there a big drop off in performance using Web Services?

Have not worked to much with Web Services. Want to know if I am
missing out on something I should be taking advantage of.

Thanks.

Top

Re: Data Access and Middle-Tier... Control Library or Web Services by Dollar

Dollar
Tue Nov 29 12:54:26 CST 2005

To clear things up, my question is the following (for Intranet Web
Applications)

Here are my tiers

Front End - ASP.NET Web Application
Middle Tier - Control Library or Web Service or Both?
Data Access - Control Library or Web Service?

Top

Re: Data Access and Middle-Tier... Control Library or Web Services by Frans

Frans
Wed Nov 30 03:13:01 CST 2005

Dollar wrote:

> Does anybody have strategies on when to through your Data Access and
> Middle-Tier into a Web Service opposed to a Control Library?
>
> I mostly deal with intranet ASP.NET web applications, and occasionally
> create web services that access my Data Access (which is in a control
> library). Right now my data access passes back datasets, datareaders,
> or XML. I know passing datasets and datareaders over web services can
> be pretty expensive.
>
> I have talked to a number of people who put everything in web
> services, but I don't see the advantage if it is an internal
> application. Is there a big drop off in performance using Web
> Services?
>
> Have not worked to much with Web Services. Want to know if I am
> missing out on something I should be taking advantage of.

Webservices are often misunderstood. Webservices should be seen as
services to which you send messages, like 'do this for me'. THey
shouldn't be used as a full tier to which you dump 1000's of rows or
request 1000s of rows from, typically because it's very inefficient to
do so.

So I'd strongly advice against a 'data-access webservice', because
that's completely missing the point of why webservices exist. It's a
big problem actually, especially since vs.net makes it so easy to
create a webservice which is actually a low-level tier.

FB

--
------------------------------------------------------------------------
Get LLBLGen Pro, productive O/R mapping for .NET: http://www.llblgen.com
My .NET blog: http://weblogs.asp.net/fbouma
Microsoft MVP (C#)
------------------------------------------------------------------------

Top