Would like to learn asp.net, ado.net

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- Previous
  - 1
    - DropdownList SelectedIndexChanged event I am using the SelectIndexChanged event for a dropdownList control. Currently, the only way the SelectIndexChange event is fired is after a user changes the selection within the dropdownlist AND clicks a command button. Does anyone know how to get this event to fire (or some other event) right after the user changes the selection w/i the dropdownList control? Tag: Would like to learn asp.net, ado.net Tag: 62961
  - 2
    - DataGrid question Does anyone know if you can disable the grid from allowing manual creation of new records, i want to only allow programitic creation and only allow editing of existinf records to take place in the grid. TIA Tag: Would like to learn asp.net, ado.net Tag: 62954
  - 3
    - problem with displaying new row Hello, My problem must be very simple to solve, but I havennt found the answer yet, so any help is appreciated. I have a form with bound controls, mostly textboxes, to an access database. When I fill the dataset the datatable which is used in the binding correctly populates the controls on the form. All navigation buttons work perfectly. The edit and delete button do their work without a problem. After a delete the label which displays current and total records by counting the rows in the table is decreased by one as it should. My only problem is after I add a new row. The row is added, but I can not navigate to it. The counter adds 1 record, so I know the add was successfull, but when I want to go to the last record it just doesnt do it. It stops at record 14/15. I use the me.databidings(dt).position = dt.rows.count - 1 to jump to the last record, which normally works, bt doesnt after I added a record. Finally, when I stop the application and restart the record the new record is added to the database and I can use it like any other record. Any ideas why I cant navigate to the new record after I created it? Thanks in advance. Tag: Would like to learn asp.net, ado.net Tag: 62944
  - 4
    - Earn $500 to $700 per Week Downloading FREE Software We know it sounds TOO good to BE true, but it?s REAL! Our International Technology firm will pay you hard cash each time FREE software is downloaded. Best of all you will only have to download ONE piece of software ONE time for FREE and you can be on your way to earning BIG! FIND OUT MORE BY VISITING http://JeromeMcCrea.PlugUsIn4Cash.com Tag: Would like to learn asp.net, ado.net Tag: 62943
  - 5
    - Login failed for user '(null)'. Reason: Not associated vs asp.net ASP.NET vs SQL Server¸ I have an ASP.NET Application In IIS I checked the Integrated Windows Authentication option In Web.Config the connection string include Integrated Security = SSPI and Impersonate=true in Web.Config When I start then Web Application I have this messge Login failed for user '(null)'. Reason: Not associated with a trusted SQL Server connection. Could you help me PS My account have the permission to connect to SQl Server the security model is base on role security I have many users Tag: Would like to learn asp.net, ado.net Tag: 62936
  - 6
    - calculated column in datatable using parent's columns Can I use the parent table's columns in the Expression property of a DataColumn? Tag: Would like to learn asp.net, ado.net Tag: 62933
  - 7
    - Weird Timeout Expired error Hello all, Here is current snapshot of our environment: ASP.NET (C#) .Net Framework 1.0 SP2 MDAC 2.71 (SP1) Windows 2000 (Build 2195 SP3) SQL Server 2000 - 8.00.760 (SP3) We are using Microsoft SqlHelper from the Application Blocks and we currently have connection pooling = no Every now and then we get two types of errors: First Error: "System.Data.SqlClient.SqlException: General network error. Check your network documentation." This error tends to go away if we refresh the browser. Second Error: "System.Data.SqlClient.SqlException: Timeout Expired. The timeout period elapsed prior to completion of the operation or the server is not responding." What is interesting about this error is that the procedure being called takes 1 parameter (a state UID) and returns within 3 seconds. I was getting an exception immediately (no 3 second delay) if I passed a state returning couple of hundred records consisting of VARCHAR and INT values, but works fine if there are fewer or no return values. Once I executed that same procedure using Query Analyzer for the problem state, the application started to work fine. It is happening on various procedure calls every few hours. I have looked on Microsoft's newsgroups, google, and on MSDN but I cannot find anything that applied to us. Any input would be appreciated. Fadi Tag: Would like to learn asp.net, ado.net Tag: 62930
  - 8
    - enforcing FK constraints on datatables that are not in a DS Hi All, I've created two datatables dtCountries and dtCities in memory. I am able to create a FK constraint on dtCities without adding these datatables to a dataset. But unless I add them to a dataset I am not able to enforce the constraint. Is there any way to enforce FK constraint without adding them to a dataset? TIA Sankar Tag: Would like to learn asp.net, ado.net Tag: 62926
  - 9
    - Returning a cursor from a stored procedure How do I capture a resultset from a stored procedure with ado.net code? ALTER PROCEDURE dbo.sp_ins_contacts ( @FName nvarchar(50), @LName nvarchar(50), @Initials nvarchar(50), @IntakeDate smalldatetime, @SSN nchar(10), @Advisor nvarchar(50 ) AS SET NOCOUNT OFF; INSERT INTO tbl_Contacts(FName, LName, Initials, IntakeDate, SSN, Advisor) VALUES (@FName, @LName, @Initials, @IntakeDate, @SSN, @Advisor); SELECT ContactID, FName, LName, Initials, IntakeDate, SSN, Advisor FROM tbl_Contacts WHERE (ContactID = @@IDENTITY) Tag: Would like to learn asp.net, ado.net Tag: 62925
  - 10
    - Returning a cursor from a stored procedure How do I capture a resultset from a stored procedure with ado.net code? ALTER PROCEDURE dbo.sp_ins_contacts ( @FName nvarchar(50), @LName nvarchar(50), @Initials nvarchar(50), @IntakeDate smalldatetime, @SSN nchar(10), @Advisor nvarchar(50 ) AS SET NOCOUNT OFF; INSERT INTO tbl_Contacts(FName, LName, Initials, IntakeDate, SSN, Advisor) VALUES (@FName, @LName, @Initials, @IntakeDate, @SSN, @Advisor); SELECT ContactID, FName, LName, Initials, IntakeDate, SSN, Advisor FROM tbl_Contacts WHERE (ContactID = @@IDENTITY) Tag: Would like to learn asp.net, ado.net Tag: 62924
  - 11
    - DefaultViewManager In MSDN library, it says that when data binding if you bind to a DataTable, in fact you bind to its DefaultView, and if you bind to a DataSet, in fact you bind to its DefaultViewManager. It is true for DataTable. If I use the following binding: dataGrid1.DataSource = dataSet1.Employee; dataGrid1.DataMember = null; Everytime I change the filter, the DataGrid changes, too. dataSet1.Employee.DefaultView.RowFilter = "Name < 'H'"; However, if I use the following binding: dataGrid1.DataSource = dataSet1; dataGrid1.DataMember = "Employee"; When I change the filter, the DataGrid is not responding. dataSet1.DefaultViewManager.DataViewSettings ["Employee"].RowFilter = "Name < 'H'"; I saw some programmers work around the problem by constructing a new DataViewManager. I wonder why Microsoft doesn't admit there is a bug, or say this behavior is by design. JT Tag: Would like to learn asp.net, ado.net Tag: 62921
  - 12
    - How do I query a DataSet to get unique IDs? Hi, I have a DataSet that contains data pairs for computers and IP addresses. Because in some cases a computer has multiple IP addresses, the HardwareID is in the DataSet multiple times. I want to create a DataView that has only the unique HardwareID's in the DataSet. How do I query my DataSet to get these HardwareIDs? Someone suggested DISTINCT but I don't know how to use DISTINCT against a DataSet to create a DataView. Could someone help me with this? Thanks, Sam Tag: Would like to learn asp.net, ado.net Tag: 62912
  - 13
    - String Error in ADo.Net Dataset code I am developing an database appliction using SQL 7 with a Visual Basic Front End using ADO.Net. When generating a dataset from the DataAdapter all the Textboxes and ComboBoxes contain the following error "'Convert' is not a member of 'String'" in the autogenerated DataSet Name.vb file. The error occurs in the following type Subs: Public Sub SetinvestigationNull() Me(Me.tablerer.investigationColumn) = System.Convert.DBNull End Sub If I comment out the "Me(Me.tablerer.investigationColumn) = System.Convert.DBNull" portion of the Sub the code compiles and runs correctly. Since I have many textboxes in the VB form, about 40, that is a lot commenting to get the application to run correctly. Is were a way to get the code to compile? Thanks Joe Tag: Would like to learn asp.net, ado.net Tag: 62909
  - 14
    - data file to database Hello I have a data file like this : 01 "" "09:04" "PLMDX " 3.20 0.35 1.74 0.23 2.49 0.17 1.37 0.18 03 02 "" "09:05" "PLMDX " 3.70 0.18 1.93 0.14 2.75 0.19 1.05 0.01 03 03... 04... ..... and i want to read each number and fileds and save it to variables to save it in to the database . with stream reader and file rader i can only read all of it as a single string , is that possible to do it with regular expression ? i don't know how . any idea ... help please Tag: Would like to learn asp.net, ado.net Tag: 62891
  - 15
    - What happens when you delete a DataRow ? I know that the state is changed to deleted, but what else happens ?, does the table make a new version of itself each time or the row ? The reason i'm asking is because I'm have a tough time understanding how making changes to more than one row ( but not more than one change per row ) and then trying to update the dataadapter can cause a concurrency error. There are no other users involved any assistance is appreciated in understanding this . . . Regards - Terry Tag: Would like to learn asp.net, ado.net Tag: 62889
  - 16
    - Oracle or SQLServer - .NET or J2EE? Hello, I am doing a very large web based database project. Over the period of 5 years, "more than 100, 000 Books" will be stored in a Database along with a LARGE amount of book attributes majorly consists of very large amount of people reviews about a book. We then need to analyze or generate reports from that large volume of STATIC data in Infinite number of ways. My questions are: Q1. Just to get general sence, Which suits the best Oracle or SQL Server for this project and Why? Keeping scalibility, volume of data, etc. in mind? Q2. Which development platform best suits best for this kind of project .NET or J2EE and Why. Q3. We have to analyze or generate reports from that STATIC data in Infinite number of ways, Which analysis technology should be used and Why? Thanks, Rafey. Tag: Would like to learn asp.net, ado.net Tag: 62884
  - 17
    - Connection Pooling with Microsoft Access? Hello, Is it possible to connection pool with Microsoft Access? I am coding in VB.NET and my application is giving me errors because the connection is still open and fetching records. Thanks! Tag: Would like to learn asp.net, ado.net Tag: 62883
  - 18
    - Unexpected error in webform any body seen this error? No error information available: E_UNEXPECTED(0x8000FFFF). Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Data.OleDb.OleDbException: No error information available: E_UNEXPECTED(0x8000FFFF). It's random occuring mostly when i update the webserver with a fresh dll, but not every time. Only way around that is to re-start the application pool or re-start iis. My hunch at this time is that this is occuring because oledb and odbc providers are hosted in the same page. That's a wild guess though, not based on anything concrete. tia Tag: Would like to learn asp.net, ado.net Tag: 62856
  - 19
    - Cannot update Access database records I have code that inserts, updates, and deletes records from an Access 2002 table using OleDbCommand and OleDbConnections. Everything works great until I place the Access database on the network and more than one person launches the application. Everyone can still insert and delete but not update (using the custom app). Any ideas? Tag: Would like to learn asp.net, ado.net Tag: 62842
  - 20
    - [ANN] Innovation to ADO.NET - Object Access Services for .NET Innovation to ADO.NET - Object Access Services for .NET New Software Matisse Software Inc. provides its native ADO.NET Data provider for Matisse 6.0, the Database for .NET. Matisse Software has pushed the envelope of Microsoft ADO.NET architecture and extended it into a powerful Object Access Services component for .NET. Unlike the standard ADO.NET data provider, which returns data in a table format to integrate seamlessly with relational products, Matisse has extended the ADO.NET architecture to return data in an object format. http://www.matisse.com/ Tag: Would like to learn asp.net, ado.net Tag: 62836
  - 21
    - Schema problem with Strongly Typed dataset I have a strongly typed dataset whose schema looks as such: <?xml version="1.0" encoding="utf-8" ?> <xs:schema id="Dataset1" targetNamespace="http://tempuri.org/Dataset1.xsd" elementFormDefault="qualified" attributeFormDefault="qualified" xmlns="http://tempuri.org/Dataset1.xsd" xmlns:mstns="http://tempuri.org/Dataset1.xsd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata"> <xs:element name="Dataset1" msdata:IsDataSet="true"> <xs:complexType> <xs:choice maxOccurs="unbounded"> <xs:element name="cc"> <xs:complexType> <xs:sequence> <xs:element name="usr" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="distributionList" nillable="true" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:simpleContent> <xs:extension base="xs:string" /> </xs:simpleContent> </xs:complexType> </xs:element> </xs:sequence> <xs:attribute name="nam" type="xs:string" form="unqualified" /> <xs:attribute name="uid" type="xs:string" form="unqualified" /> </xs:complexType> </xs:element> </xs:sequence> </xs:complexType> </xs:element> </xs:choice> </xs:complexType> </xs:element> </xs:schema> I have a test function in a windows form in which I try to fill the dataset up with xml. My function looks as such: Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim ds As New Dataset1 Dim xreader As XmlReader Try Dim stream As New System.IO.StringReader("<cc>" & _ "<usr uid=""123"" nam=""Test User"">" & _ "<distributionList>testing</distributionList>" & _ "</usr>" & _ "</cc>") xreader = New XmlTextReader(stream) ' I am crashing here ds.ReadXml(xreader, XmlReadMode.InferSchema) MsgBox(ds.GetXml) Catch ex As Exception MsgBox(ex.Message) End Try End Sub My believe my problem lies in the schema. If I specify multiple or zero distributionList nodes the xml is read into the dataset correctly. If I specify just one distributionList node I get a "Specified cast is not valid". Am I missing something in the schema? Thanks, Collin Tag: Would like to learn asp.net, ado.net Tag: 62835
  - 22
    - Proposed method implementation in a new generic data access component I've mentioned in other posts that I am creating a generic ADO.NET project. Version 1 is already done actually (see my signature, and read synopsis in docs) I am making alot of additions in version 2. One being the addition of a bunch of classes that form a "Gen" provider... (GenConnection, GenDataAdapter, etc...). In the constructor of each data object I'm adding an additional parameter specifying the "DbContext". For example the standard IDbCommand constructor... public IDbCommand() //creates a standard Command, must set properties separately In my GenCommand as proposed... /// <summary> /// This constructor will use the connection of the /// DbContext if it has a ConnectionString assigned. /// </summary> /// <param name="ctx"></param> public GenCommand(DbContext ctx) { _ctx = ctx; _cmd = _ctx.DbTemplate.Command(); if (_ctx.ConnectionString.Length > 0) { _cmd.Connection = _ctx.Connection; } } Do you think it is a bad idea to imply the Connection from the context? I require the context to be able to dynamically load the appropriate underlying provider (Sql, OleDb, ODbc, etc...). But should I also use it to imply the connection. If the user desired they could overide it and specifiy a different connection. However, for those lazy people, the context gives enough info to specify the connection. It behaves different than all the other providers, which is why I'm wondering if it is a bad idea? Any advice? Which would you prefer as a user? -- Michael Lang, MCSD See my .NET open source projects http://sourceforge.net/projects/dbobjecter (code generator) http://sourceforge.net/projects/genadonet ("generic" ADO.NET) Tag: Would like to learn asp.net, ado.net Tag: 62830
  - 23
    - how can I get the path for the error ORA-01458 it is told on the microsoft web site that to resolve this=20 problem i must contact "the microsoft support service"=20 and they will send me the patch. THERE IS TONS OF MICROSOFT SUPPORT SERVICE... which one=20 must i contact and how much it will cost... I leave in qu=E9bec - canada (i speak french) thanks Tag: Would like to learn asp.net, ado.net Tag: 62827
  - 24
    - Why is this login failing? I am using VS in conjunction with SQL Server 2000. I am trying to create a new SQLConnection but am getting an error message of "Login failed. Not associated with a trusted SQL Server Connection" I drag a SQLConnection to my components tray. In the Connection String property I say New connection. I give the server name (which is the name of my computer) and put the radio on specific name and password. I enter a user name of sa and a password of xxx. I click on the field "Select the database on the server" and get the above mentioned error, followed by "Login failed, Catalog info can not be retrieved". In the past I have solved this problem by going into SQL Server and in the Server, Properties, Security tab changing the authenication to SQL Server and Windows. My notes indicate that in the past when I've had this problem it was because the authentication was not set to mixed. However this does not seem to fix the problem in this case. Does anyone have any idea what's going on? Tag: Would like to learn asp.net, ado.net Tag: 62826
  - 25
    - Record Locking? How would I go about locking records using ADO.Net? It seems that everything in ADO.Net is based upon opening a connection, retrieving data, and closing the connection. To keep the records locked, is it as simple as leaving the database connection open? ~Thanks Tag: Would like to learn asp.net, ado.net Tag: 62817
- Next
  - 1
    - What is the best way to delete multiple rows Grid, DataAdapter, Access Source What is the best way to delete multiple rows bound to a datagrid without getting a concurrency exception. TIA Tag: Would like to learn asp.net, ado.net Tag: 62816
  - 2
    - Connection String with Access Workgroup Info (mdw) I've searched through several forums without finding a definitive answer to this question: What is the proper syntax for a connection string that is connecting to an Access 97 db with workgroup security applied? I tried the following. I don't get an error, but it also displays NO results: Public Shared ReadOnly OleDbConnectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=DBQ=c:\CORmandOTweb\NewSecure CORMandatoryOTList.mdb SystemDB=c:\inetpub\wwwroot\aspdotnet\cormandot\db\corrections.mdw;UID=usern ame;PWD=anything" Also tried: Dim cnn As OleDbConnection = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Persist Security Info=false;Data Source=" & System.Web.HttpContext.Current.Server.MapPath("/CORmandOTweb/NewSecure CORMandtoryOTList.mdb") & "; Jet OLEDB:System Database=c:\inetpub\wwwroot\aspdotnet\cormandot\db\corrections.mdw;UserID=us ername;Password=anything") All help will be greatly appreciated! Lynnette Tag: Would like to learn asp.net, ado.net Tag: 62802
  - 3
    - Concurrecy Error, anyone see what I'm doing wrong here ? This code takes the Person index drom the datagrid dgPeople and uses it to delete all the records from the dgEvents grid and underlying records. It works but i do get that concurrency message Case "Delete" Try 'open connection con.Open() 'Setup the Delete Command for events for this person DeleteCmd.CommandText = "DELETE * FROM [Events] WHERE PersonIndex = ?" DeleteCmd.Connection = con DeleteCmd.CommandType = CommandType.Text DeleteCmd.Parameters.Add(New System.Data.OleDb.OleDbParameter("Original_PersonIndex", System.Data.OleDb.OleDbType.Integer, 0, System.Data.ParameterDirection.Input, False, CType(0, Byte), CType(0, Byte), "PersonIndex", System.Data.DataRowVersion.Original, Nothing)) Dim r As DataRow PersonIndex = CType(dgPeople.Item(dgPeople.CurrentRowIndex, 0), Int32) For Each r In tableEvents.Rows If PersonIndex = CType(r.Item(0), Int32) Then r.Delete() End If Next daEvents.DeleteCommand = DeleteCmd daEvents.Update(tableEvents) Catch ex As OleDbException MessageBox.Show(ex.Message) Finally con.Close() End Try Tag: Would like to learn asp.net, ado.net Tag: 62788
  - 4
    - Installation of VB.NET Program Let's say now that I have my program finished. How do I go about writing a setup program that would install the required directories, and place my files where they need to be? For starters, I have my exe file, and two jpg files that I want to bundle in an install program that will just create a folder on the desktop, and then create those files automatically. How could I do that? Also, what's the difference between Build Solution, Rebuild Solution, Build ProjectName, Rebuild ProjectName? Thanks Jordan Tag: Would like to learn asp.net, ado.net Tag: 62787
  - 5
    - ADO.NET xxxConnection best practice hello In my project i have classes whoes read,update , insert database for exemple in one method , i do 20 request which is best the practice ? a) open and close ADO.NET connection for each requests (using pooling connection but slower cause of .open() method ?) or b) open one connection for method , excute requests , close connection ( the pooling connection is use for the project and calls methods but not in each methods ) rq: my question is NOT for Execute multi request on one command , and NOT for using stored procedure thanks Tag: Would like to learn asp.net, ado.net Tag: 62783
  - 6
    - many repeatable operations Hi I have in my project (C#) many operation such as add, update, remove record from table. How to automate this. I don't wan to use grid. Are some code generators or something else to get this. The best for me is dialog with fields to fill in and verification of filled fields. Thanks Konrad Tag: Would like to learn asp.net, ado.net Tag: 62771
  - 7
    - Extending Typed "DataTables" I am facing the following problem in my applications and would like suggestions from you guys. My database schema has changed many times over the years and keeps chaging frequently according to specific client needs. My business layer (webservices) returns datasets to the thick client. The problem is that as the database changes so often, more than 800 datasets will have to be changed everytime. The solution suggested was as follows: a) Create 1 DataTable for each TABLE in the database. b) Create own DataSet for each visible screen or processing function by addind DataTables to this DataSet. c) Add Ref Contraints manually to this custom DataSet. This way, if the database changes, only one single DataTable class (schema) in the application will have to be changed. Now my problem is that i want to use Typed Datasets and Typed DataTables. What would be the best solution for this scenario. As mentioned on MSDN, DataTables can be instantiated independent of DataSets. In this case, the schema for the DataTable and the constraints are added manually in the code. But I could not find anything about extending Typed DataTables and using them independent of the DataSet. There is a powertoy by Shawn Wildermuth that helps you extend Typed DataSets, but i couldn't extrapolate his ideas to fit my requirements. Any ideas what the best thing for me would be ? Thanks, Nishith Tag: Would like to learn asp.net, ado.net Tag: 62769
  - 8
    - System.Type.GetType("System.Data.SqlTypes.SqlString") problem Hi, I'm trying to create a DataColumn with the following code: DataColumn dc = new DataColumn("CustomerID", System.Type.GetType("System.Data.SqlTypes.SqlString")); but the GetType method does not return a valid type. If I use "System.String" it works. If I create an instance of System.Data.SqlTypes.SqlString and the use the instance's GetType method inherited from System.Object I can get the type but I would like to get the type directly from Type.GetType. Can anyone see what I'm doing wrong? Is there another way to get what I need with a single method call? Thanks...Ron Tag: Would like to learn asp.net, ado.net Tag: 62764
  - 9
    - Transaction IsolationLevel Hi, I found the following statement regarding IsolationLevels in MSDN: "If changed during a transaction, the expected behavior of the server is to apply the new locking level to all statements remaining." (http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html /frlrfsystemdataisolationlevelclasstopic.asp) My question is: if I already have a SqlTransaction running, and want to change the isolation level in the middle, how do I change it? I found that the SqlTransaction.IsolationLevel property is ReadOnly. Thanks for any help. Tag: Would like to learn asp.net, ado.net Tag: 62760
  - 10
    - Updating BLOBS to database I need to store the logo of my enterprise in a image field. I find the way to retreave this field, but a cant´t find the way to store my logo's file in a table. I'am using ado.net Thanks Tag: Would like to learn asp.net, ado.net Tag: 62749
  - 11
    - DataTable Events? I am getting started with DataTables and the DataGrid control. I want to find out when the user adds a row to a DataGrid, but I can't find a 'new row' or 'row added' method in either the DataGrid control or the DataTable class. I have bound a DataGrid to a stand-alone, in-memory DataTable. The user can edit the DataGrid cells and add new rows. When the user adds a new row, the calls all show "(null)", since they don't yet have values. I'd like to know when the user adds a new row, so I can plug in some default values, or do something to supress the "(null)" display in the cells. Is there an easy way to do that? Is an event fired when a user adds a new row? Thanks. -- Dave Veeneman davidv@nospam.com (actual domain is my last name) Tag: Would like to learn asp.net, ado.net Tag: 62748
  - 12
    - Autoincrement Key values in Relationships ADO.NET and Autoincrement fields. Recently, while attempting to use .NET to build an interface for a new system, I came upon the issue of using Autoincrement fields as Key values. In and of themselves, they are not terribly troublesome, but when used as part of a Key defining a Parent-Child relationship, things get a little sticky. Per the MicrosoftPress book, ADO.NET by David Sceppa, handling Autoincrement values in Parent-Child relationships is no bother at all. In chapter 11 - Advanced Updating Scenarios : Section 'Working with Autoincrement Values and Relational Data', Sceppa states, (after fetching the new Autoincrement value for the Parent record from the database)"...how do you apply the new Autoincrement values to the pending new line items? Actually, you don't. You let ADO.NET do the work for you through the DataRelation.". That statement is only half right. ADO.NET will in fact update the values through the DataRelation, but in the process, it changes the RowState of the (child) records from 'Added' to 'Modified'. Since this property is read- only, this effectively prevents the child records from being INSERTed into the database (because the DataAdapter now believes these records are NOT NEW, but simply existing records that have been modified. Using this methodology, your detail data will never get stored to the Database. Ever. In his book, Sceppa also discourages the use of Autoincrement values in favor of the GUID. Since that value can be generated by either the client or server, it is much easier to handle since you do not need any special code to retrieve the values from the Database after the row has been added. Except for the fact that GUID values CAN BE DUPLICATED, and the fact that they are four times larger than an (SQL)Int, this would probably be a good suggestion. Even if the uniqueness could be guaranteed, who wants to use a 16-byte random 'string' as a key value for lookups and cross referencing between tables!?!? After fighting with this particular issue for several days (and nights), and repeated attempts to find something resembling an answer on Microsoft's many websites, I found something that actually works, and is not terribly difficult to achieve. I would like to say that the idea, if not the code, came from Microsoft. It didn't. Let's use the standard ORDERS and ORDERDETAILS tables to illustrate.... ORDERS : PrimaryKey = (ORDER_ID) --------------------------------- ORDER_ID : Autoincrement (-1, -1) CUSTOMER_ID : Int .... ORDERDETAILS : PrimaryKey = (ORDER_ID + LINEITEM_ID) ---------------------------------------------------- ORDER_ID : Int LINEITEM_ID : Int .... DataRelation -------------------------------- Parent : ORDERS("ORDER_ID") Child : ORDERDETAILS("ORDER_ID") Let's say that a single new order has been added to the DataSet and has been assigned an ORDER_ID of -1. the new records would look something like this... ORDERS.Rows(0)("ORDER_ID") = -1 ORDERS.Rows(0)("CUSTOMER_ID") = 7026 .... ORDERS.Rows(0).RowState = Added ORDERDETAILS.Rows(0)("ORDER_ID") = -1 ORDERDETAILS.Rows(0)("LINEITEM_ID") = 27 .... ORDERDETAILS.Rows(0).RowState = Added In order for the Database assigned Autoincrement value to propagate to the child table in the relationship, you need to use the Parent tables Select method, and NOT GetChanges since GetChanges will not cascade the values to the ORDERDETAILS DataTable. The call would look something like this.... nEffectedRows = sdaORDERS.Update(ds.ORDERS.Select ("ORDER_ID < 0")) ----->Insert statement is as follows.... "INSERT INTO dbo.ORDERS(CUSTOMER_ID) "_ "VALUES (@CUSTOMER_ID) ; "_ "SELECT ORDER_ID, CUSTOMER_ID FROM dbo.ORDERS "_ "WHERE (@ORDER_ID = @@IDENTITY)" This will add the new ORDER record to the Database and return the new database assigned ORDER_ID, which in turn is stored in the appropriate ORDERS datarow. If the DataRelation is set up correctly and in effect, the ORDER_ID values in the Child record(s) will also be updated with the correct ORDER ID. This makes our records look like this... ORDERS.Rows(0)("ORDER_ID") = 99 ORDERS.Rows(0)("CUSTOMER_ID") = 7026 ORDERS.Rows(0).RowState = Unchanged ORDERDETAILS.Rows(0)("ORDER_ID") = 99 ORDERDETAILS.Rows(0)("LINEITEM_ID") = 27 ORDERDETAILS.Rows(0).RowState = Modified ... This brings us to the problem with using this method. At this point, we have called the Update method for the ORDERS DataAdapter, but NOT for the ORDERDETAILS DataAdapter. If you look at the RowState for the ORDERDETAILS row you will see that it has been changed from 'Added' to 'Modified'. If you now try to send this row to the DataAdapters Update method, it will attempt to UPDATE it rather than INSERT it. Obviously this fails since the row does not exist in the Database. What makes this really fun to deal with is the fact that the RowState property is READONLY. Microsoft does not offer any solution to this. Sceppa is obviously unaware of this problem since he goes on to say, "Once the new rows in the order details DataTable contain the appropriate values for the OrderID column, you can successfully submit the pending new rows to your database". No biggie. It's not the first time Microsoft has left out a detail or two. Solution. It took me about 5 days to find a combination of tactics that actually worked. The sequence of events are the same as what is described above, but with a couple of extra steps tossed in. The solution itself isn't terribly difficult to code, infact it's rather simplistic. What made it difficult was trying to do it 'their way'. The brief run-down is as follows.... <data has already been added - we are about to update the database with our changes > //------------------------------------------------------ //------------------------------------------------------ Dim xx, yy As Int16 Dim tOrdersAry() As DataRow Dim tDetailsAry() As DataRow ' Get our array of (POINTERS to) the ADDED ROWS... tOrdersAry = _ ds.ORDERS.Select("", "ORDER_ID", Added) tDetailsAry = _ ds.ORDERDETAILS.Select("", "ORDER_ID", Added) ' Now, update the ORDERS Table with the NEW records... xx = sdaORDERS.Update(tOrdersAry) Dim tempTable As DataTable tempTable = <dsClassDef>.ORDERS.Clone ' The ORDER_ID field is an Autoincrement column. ' TURN IT OFF!!!!! tempTable.Columns("ORDER_ID").AutoIncrement = False ' Copy over all the data from the real (Details) DataTable ' (which includes the new, correct ORDER_ID value)... Dim tmpRow, tmpRow2 As DataRow For Each tmpRow In tDetailsAry tmpRow2 = tempTable.NewRow tmpRow2("ORDER_ID") = tmpRow("ORDER_ID") tmpRow2("CUSTOMER_ID") = tmpRow("CUSTOMER_ID") tempTable.Rows.Add(tmpRow2) Next ' Update the Database with the 'Added' records... yy = sdaOREDRDETAILS.Update(tempTable) //------------------------------------------------------ //------------------------------------------------------ One detail left to do at this point is call the AcceptChanges method for the -real- rows in the ORDERDETAILS DataTable. Since this is dependant upon your particular handling of the transaction, I do not include that code in this example, though I would suggest handling the INSERTS in a separate transaction and calling the AcceptChanges method for each added (detail) row rather than for the entire table after all updates, inserts, and deletes. In closing, I would just like to add that under normal circumstances I would not have bothered to comment on this problem. I have in this case because Microsoft has documented this situation to a fair degree of detail, but has done so incorrectly, ineffectively, and when consulting more than one source, in a conflicting manner. I paid good money to buy a MicrosoftPress book since they, by all rights, should be the absolute experts on the subject. I then added to my confusion by consulting the Microsoft website to clarify, only to find more wrong answers (though stated in a very matter-of-fact manner). I freely admit that I have never, and I mean never, really liked Microsoft. Mostly because of their business practices, but also because of the quantity of bugs and known problems within their software (which will be fixed in the next release for only $xxx.xx!!). When the company I work for decided to use .NET for a system re-write, I began investigating it, and to my own surprise, I was very pleased with what I found. For the first time in twelve years, I had something NICE to say about Microsoft. However, as with everything else from MS, once you get down to the details, the documentation ALWAYS works better than the actual software. Tag: Would like to learn asp.net, ado.net Tag: 62743
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    - Problem with IConvertible and text column I'm trying to execute a stored procedure, which receives some parameters, to insert a row in a table. One of those parameters is defined with text data type, just as the column in the table. When I call that sp from my C# app, I get an exception of "Object must implement IConvertible". Although I call stored procedures daily, this is the first time I see this exception, and is the first time I use a text parameter in a sp. This is the C# code ... SqlParameter []parametros = new SqlParameter[4]; parametros[0] = new SqlParameter("@Id",SqlDbType.Int); parametros[1] = new SqlParameter("@Contenido",SqlDbType.Text); parametros[2] = new SqlParameter("@PalabrasClave",SqlDbType.VarChar,2048); parametros[3] = new SqlParameter("@Nombre",SqlDbType.VarChar,255); parametros[0].Value = objCanal.Id; parametros[1].Value = objCanal.Contenido; parametros[2].Value = objCanal.Palabras; parametros[3].Value = objCanal.Nombre; if (SqlHelper.ExecuteNonQuery(ConnectionString,"InsertarCanalEstatico",parametros) == 0) throw new Exception("Fila no insertada"); ... and this is the sp ALTER PROCEDURE dbo.InsertarCanalEstatico ( @Id int, @Contenido text, @PalabrasClave varchar(2048), @NombreCanal varchar(255) ) AS declare @cant int select @cant = count(*) from contenido where Id = @Id if @cant = 1 update Contenido set Contenido = @Contenido, PalabrasClave = @PalabrasClave, NombreCanal = @NombreCanal where Id = @Id else insert into Contenido (Id,Contenido,PalabrasClave,NombreCanal) values (@Id,@Contenido,@PalabrasClave,@NombreCanal) Tag: Would like to learn asp.net, ado.net Tag: 62739
  - 14
    - Problems connecting to Oracle using Oracle Provider for .Net Framwork Hello, Trying to use .Net oracle provider, but am getting the following error. I am using Oracle 9i client to Oracle 9i. Any ideas? Could not create an environment: OCIEnvCreate returned - 1. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Exception: Could not create an environment: OCIEnvCreate returned -1. Source Error: Line 27: Dim myConnection As OracleConnection = New OracleConnection(strConn) Line 28: Line 29: myConnection.Open() Line 30: Line 31: myConnection.close() Source File: c:\inetpub\wwwroot\HL7Delete\HL7Delete.aspx.vb Line: 29 Stack Trace: [Exception: Could not create an environment: OCIEnvCreate returned -1.] System.Data.OracleClient.DBObjectPool.GetObject (Boolean& isInTransaction) System.Data.OracleClient.OracleConnectionPoolManager.GetPo oledConnection(String encryptedConnectionString, OracleConnectionString options, Boolean& isInTransaction) System.Data.OracleClient.OracleConnection.OpenInternal (OracleConnectionString parsedConnectionString, Object transact) System.Data.OracleClient.OracleConnection.Open() HL7Delete.HL7Delete.getConfirmation() in c:\inetpub\wwwroot\HL7Delete\HL7Delete.aspx.vb:29 HL7Delete.HL7Delete.Page_Load(Object sender, EventArgs e) in c:\inetpub\wwwroot\HL7Delete\HL7Delete.aspx.vb:23 System.Web.UI.Control.OnLoad(EventArgs e) System.Web.UI.Control.LoadRecursive() System.Web.UI.Page.ProcessRequestMain() Tag: Would like to learn asp.net, ado.net Tag: 62735
  - 15
    - SQL Query for Datagrid Paging I under stand how to pull the results for all but the first page in the grid using one query or stored proc. If I could specify TOP 0 in the sub query, you would think that would work. Do I need to create another stored proc to pull the results for the first page of the datagrid? SELECT TOP 3 id, name FROM mytable WHERE id NOT IN (SELECT TOP 0 id FROM myTable ORDER BY name) ORDER BY name TIA, Steve Tag: Would like to learn asp.net, ado.net Tag: 62734
  - 16
    - timberline hello does someone knows how to access timberline accounting softwares database using .net? Tag: Would like to learn asp.net, ado.net Tag: 62724
  - 17
    - @@ROWCOUNT I am trying to return the Row Count from a stored proc Here is the sp CREATE PROC AS SELECT * FROM accounts RETURN @@ROWCOUNT GO Here is where I am pulling the return value, but I am getting nothing??? All the return parameters are set correctly. lblMessage.Text = cmdDepositoriesRetrieve.Parameters("@returnvalue").Value TIA, Steve Wofford www.IntraRELY.com Tag: Would like to learn asp.net, ado.net Tag: 62719
  - 18
    - Flexible Data Provider Architecture Hello, I need advice on how to design flexible data handling for an app that meets the following general installation options: 1. data on local machine, single user, probably using Access or FoxPro 2. data on network, multi-user, client server, SQL Server or Oracle 3. data on web service using SQL Server and IIS The option chosen must be transparent to the client. Currently my design is based on separating the client app from the data provider. The client instantiates a class from a separate dll that handles communication between the client and the data - currently SQL Server. I figured that I would later expand data handling to other data sources through subclassing. While I haven't since ruled this out, I'm guessing that the web service version will throw a wrench into this approach. The question is how to provide elegant and transparent switching between data handling code for a flexible and growing list of data providers. I'm tempted to implement an intermediate "generic" wrapper class containing all the methods needed by the client. The wrapper class would then farm out the actual work to provider-specific classes based on the provider in use. Unfortunately, I have yet to work with web services, so anything I come up with at this point would be a guess. Any advice would be appreciated. Randy Tag: Would like to learn asp.net, ado.net Tag: 62715
  - 19
    - Sending Certain Fonts to Printer I am trying to send a 'Control' Font to a receipt printer. This is suppose to execute an auto-cut and open the cash drawer. Does anyone have an idea how I force a particular font to the printer? thanks Tag: Would like to learn asp.net, ado.net Tag: 62698
  - 20
    - "Executereader requires an open and available connection" error I have an asp.net page that stopped running properly giving the error below. The app uses a SQL Server 2000 on another server. Enterprise Manager and Query analyzer on the web server can connect to that sql server just fine and run queries. I rebooted the web server and made aspnet member of the admin group. I don't know why the error mentions open connections if I can open several query anaylzer windows using the same sql server credentials as the asp.net is using. I suspect it's an issue with ado.net or .net in general. Any ideas? error message: "Executereader requires an open and available connection Karim Tag: Would like to learn asp.net, ado.net Tag: 62691
  - 21
    - SQL Server connection string works with IIS 5.1 but not IIS 6 in ASP.NET Hello, I have a very simple aspx file that runs on WinXP Pro IIS 5.1 and connects to a SQL Server 2k DB running on a Win2003 Server box. It works fine with the connection string below (X replace real values for security). "packet size=4096;user id=XXX;pwd=XXX;data source='XX.XXX.XXX.X';persist security info=False;initial catalog=XXX" When I place this aspx file on the Win2003 Server under a Virtual Directory I get the following error. "SQL Server does not exist or access denied" I have replaced the IP address for the data source value in the original connection string with every imaginable option (local, localhost, <servername\sqlservername>, etc.) to no avail. I have added ASPNET, NETWORK SERVICES, & SYSTEM as logins to the SQL Server and the database I am trying to access. I have modified my <processModel section of the machine.config file to use the SYSTEM user name. Does anyone have any idea what is going on? Thank you ahead of time for your suggestions. John Tag: Would like to learn asp.net, ado.net Tag: 62690
  - 22
    - Equivalent to Command.Parameters.Refresh Hi, Does anyone know what is the equivalent of Refresh method in VB6 for ado.net command object. Thanks in advance, Ray Tag: Would like to learn asp.net, ado.net Tag: 62683
  - 23
    - 'ResourcePool' is not supported on the current platform Aloha! Im getting the following message when I'm trying to use the data adapter: 'ResourcePool' is not supported on the current platform I'm running Windows 2000 professional, SQL Server 2000 and .Net 1.1. What is causing this? I've seen that other people have had the same problem in other forums. however I haven't seen any answer to what is causing it! Help! Regards, Max. Tag: Would like to learn asp.net, ado.net Tag: 62681
  - 24
    - master-detail DataGrid's for many-to-many relationship My database contains a STUDENTS table, a COURSES table, and an ENROLLMENTS table. The ENROLLMENTS table represents the many-to-many relationship between students and courses. I would like to have a master-detail pair of DataGrid's. The master grid contains students, and the detail grid contains the courses in which the selected student is enrolled. Master-detail grids are easy when there is a parent-child relationship between two tables. However, in my case the parent child relationship is between the STUDENTS and ENROLLMENTS tables (and the COURSES and ENROLLMENTS). How can I get a pair of DataGrid's to act as master-detail for this many-to-many relationship? Thanks, Dennis Tag: Would like to learn asp.net, ado.net Tag: 62680
  - 25
    - multiple types of connections Hey all, I have a dll written in Vb.Net which has all my application's database access. I used OdbcConnection in it for legacy compatibility. I want to use the same dll to access Sql Server 7.0 and higher with SqlClient library when the database allows its use. I am going to use OdbcConnection for Sql Server 6.5 access still. What is the best way of using in the same code for two or more data access libraries? here is a simple code... Would I have to write one function for each data access type? Dim conSala As OdbcConnection Dim adpSala As OdbcDataAdapter conSala = New OdbcConnection conSala.ConnectionString = "DSN=Multi;uid=sasa;pwd=sasa;" adpSala = New OdbcDataAdapter("SELECT CDPARAM FROM PARAMS ORDER BY CDPARAM", conSala) dstSala = New DataSet Try adpSala.Fill(dstSala, "Params") Catch ex As Exception Return False Finally conSala.Close() conSala = Nothing adpSala = Nothing End Try Return True Tag: Would like to learn asp.net, ado.net Tag: 62678

Hello. I am looking for some individual tutoring on ASP.Net and ADO.Net, in
conjunction with reading/writing to an Access database. Ideally, I would
like to get a "hello world" database up and running. I have learned a bit
about each of these technologies through reading, although I am finding it
rough going combining them to get a real-world project going.

Is there anybody who'd be available for this sort of thing? I own Office
2000 and Visual Studio.Net Professional, as well as have a .Net web hosting
account.

I live in San Francisco, CA, and can pay (what I think is) a reasonable
hourly fee.

If anybody is interested, please email me at msofficeguyNOSPAM@yahoo.com.
(remove the NOSPAM part)

Thanks.

Top

Re: Would like to learn asp.net, ado.net by Ken

Ken
Sat Aug 16 11:28:04 CDT 2003

While I don't do private tutoring, you might want to see if Webmatrix is the
product for you. It now works with MS Access:

http://www.asp.net/webmatrix/guidedtour/section15/dgcodebuilder.aspx

Ken
MVP [ASP.NET]
--
Microsoft MVPs have a question for *you*: Are you patched against the Worm?
http://www.microsoft.com/security/security_bulletins/ms03-026.asp

"MS Office Guy" <msofficeguyNOSPAM@yahoo.com> wrote in message
news:%23I1ByJBZDHA.384@TK2MSFTNGP12.phx.gbl...
Hello. I am looking for some individual tutoring on ASP.Net and ADO.Net, in
conjunction with reading/writing to an Access database. Ideally, I would
like to get a "hello world" database up and running. I have learned a bit
about each of these technologies through reading, although I am finding it
rough going combining them to get a real-world project going.

Is there anybody who'd be available for this sort of thing? I own Office
2000 and Visual Studio.Net Professional, as well as have a .Net web hosting
account.

I live in San Francisco, CA, and can pay (what I think is) a reasonable
hourly fee.

If anybody is interested, please email me at msofficeguyNOSPAM@yahoo.com.
(remove the NOSPAM part)

Thanks.

Top

Re: Would like to learn asp.net, ado.net by G�nen

Gönen
Sat Aug 16 13:37:55 CDT 2003

i think
http://www.aspalliance.com/aspxtreme/
is a good place to start with good exemples..
you have to read a little more on ADO.NET but you'll see it'not very
difficult

if you have any problems feel free to contact me =)
geren@gsu.edu.tr
Gönen.

Top