There are several parts involved in allowing this method to work: has been created, it is necessary to generate the additional statements required for inserting, updating and deleting data.
There is even a short-cut method of creating those 3 SQL commands called the Command Builder. New Row() dr("LName") = "Doe" dr("FName") = "John" dr("IDNo") = 120 dt. ) cb = New Ole Db Command Builder(da) Try ' Now let's write the changes back to the database da. ") Exit Sub End Try If you've got a sharp eye, you'll notice that we create a new Ole Db Command Builder object, and yet never make any references to it!
After you give the Command Builder a copy of the SELECT command you used originally, it will generate the 3 SQL commands for INSERT, DELETE, and UPDATE. OLEDB.4.0; Data Source=..\test.mdb" ' a Command object to get the data cmd. Command Text = "Select * from Table1" ' a Data Adpter object to fill the data da. Update(dt) Catch ex As Exception Msg Box("Yikes, Can't update the database" & vb Cr & ex. The mystery is solved when you figure out that the Data Adapter object is passed "by reference" and the changes are made to the Data Adapter directly. let's say you've got a Data Grid on a window form and have bound a Data Table to it. Click Dim dt_changes As Data Table Dim cb As Ole Db Command Builder Dim rows As Integer ' Let's see if anybody made any changes to the table via the datagrid dt_changes = dt. Exclamation) End Try Else Msg Box("Hey, there's nothing to update") End If ' No need to close any database connections...
This decouples the working data set from the database.
This decoupled mode of working with data is supported by Connector/Net.
Note: An Invalid Operation Exception will occur if the Db Data Adapter.
The Sql Data Adapter also includes the Sql Data Adapter. This setting indicates that the value of the parameter is not set manually, but is taken from the particular column in the currently processed row.
Note: If you are using SQL Server stored procedures to edit or delete data using a Data Adapter, make sure that you do not use SET NOCOUNT ON in the stored procedure definition. Table Mappings properties to facilitate the loading and updating of data. Update Command are generic templates that are automatically filled with individual values from every modified row through the parameters mechanism.
Sql Data Adapter is used in conjunction with Sql Connection and Sql Command to increase performance when connecting to a SQL Server database.
So after you've added, deleted, and modified the data in the Data Table, it's time to write those changes back...
to do this, you use the Data Adapter's Update() method.
, the connection to the database was continually maintained, unless explicitly closed.