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Using ADO Programmatically

Using ADO Programmatically. The Connection Object and the Command Object. Using ADO Programmatically. To perform ADO operations without the aid of the ADO Data control: Establish a connection to a data source Define a command Execute the command

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Using ADO Programmatically

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  1. Using ADO Programmatically The Connection Object and the Command Object

  2. Using ADO Programmatically • To perform ADO operations without the aid of the ADO Data control: • Establish a connection to a data source • Define a command • Execute the command • Commands may or may not return records. If they do, create a recordset. • Manipulate the records in the recordset as desired.

  3. ADO Object Hierarchy • A Connection object represents an open connection to a data source. Connection Errors Command Recordset

  4. Connection Object Properties • ConnectionString • ConnectionTimeout • CommandTimeout • Mode • Provider

  5. Connection Object Methods • Open • Close • BeginTrans • CommitTrans • RollbackTrans

  6. Building the Connection Object Programmatically • Create an instance of an ADO Connection object • Set the necessary arguments for the ConnectionString property of the Connection object. • Call the Open method of the Connection object.

  7. ConnectionString Property • The ConnectionString property is a string with which you specify a data source. • It defines connection information in the form of argument = value pairs separated by semicolons (;). ADO supports the following arguments: • Provider • Data Source • User ID and Password • File Name • Remote Provider and Remote Server

  8. Creating an Instance of the ADO Object • You must create an instance of a particular ADO object before you can use it. • Example: Dim conMagnet As New ADODB.Connection

  9. Private Sub Form_Load() ' Declare the Connection object. Dim conMagnet As New ADODB.Connection ' Define the properties for the Connection object ' then open the connection. conMagnet.Mode = adModeShareDenyNone conMagnet.CursorLocation = adUseClient conMagnet.Provider = "Microsoft.Jet.OLEDB.4.0" conMagnet.ConnectionString = "Data Source=A:\Magnet.mdb” conMagnet.Open End Sub

  10. The Command Object • Properties • ActiveConnection • CommandType • adCmdText, adCmdTable, adCmdStoredProcedure • CommandText • CommandTimeout • Methods • Execute • Cancel

  11. Private Sub Form_Load() ' Declare the Connection and Command objects. Dim conMagnet As New ADODB.Connection Dim cmdMagnet As New ADODB.Command ' Define the properties for the Connection object ' then open the connection. conMagnet.Mode = adModeShareDenyNone conMagnet.CursorLocation = adUseClient conMagnet.Provider = "Microsoft.Jet.OLEDB.4.0" conMagnet.ConnectionString = "Data Source=A:\Magnet.mdb" conMagnet.Open ' Define the propeties for the Command object. Set cmdMagnet.ActiveConnection = conMagnet cmdMagnet.CommandType = adCmdTable cmdMagnet.CommandText = "tblOrderMaster“ End Sub

  12. ' Module level variable to store a reference to the form's recordset. Private rstCurrent As New ADODB.Recordset Private Sub Form_Load() Dim conMagnet As New ADODB.Connection Dim cmdMagnet As New ADODB.Command conMagnet.Mode = adModeShareDenyNone conMagnet.CursorLocation = adUseClient conMagnet.Provider = "Microsoft.Jet.OLEDB.4.0" conMagnet.ConnectionString = "Data Source=A:\Magnet.mdb" conMagnet.Open Set cmdMagnet.ActiveConnection = conMagnet cmdMagnet.CommandType = adCmdTable cmdMagnet.CommandText = "tblOrderMaster“ rstCurrent.Open cmdMagnet End Sub

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