HOWTO: Call Stored Procedures Using Data Access Objects

• Microsoft Visual Basic Professional and Enterprise Editions for Windows, versions 5.0, 6.0
• Microsoft Visual Basic Professional and Enterprise Editions, 16-bit and 32-bit, for Windows, version 4.0

SUMMARY

This article describes how to use Data Access Objects (DAO) to call Microsoft SQL stored procedures from Microsoft Visual Basic for Windows. A stored procedure is a precompiled collection of SQL statements, often including control-of-flow language.

NOTE: This article assumes you already know how to open an ODBC database.

MORE INFORMATION

The method of calling depends on whether the SQL stored procedure returns records or not. For example:

1. Stored procedures that do not return records (or rows) can be executed from Visual Basic with the Execute method in Visual Basic as follows:
   

   
         MyDb.Execute "sp_name", dbSQLPassThrough
         i = MyDb.RowsAffected
    

   You can also use ExecuteSQL:
   

   
         i = MyDb.ExecuteSQL("sp_name")
    

   However, this syntax is obsolete, and you should replace it with the Execute method and RowsAffected property syntax given at the beginning of this section.
   
   The Execute (and ExecuteSQL) method runs the stored procedure sp_name. The RowsAffected property returns the number of rows the stored procedure affected. This method is strictly for action queries such as:
   

   
         Delete Authors where name like "fred%"
      

   Using Execute with an SQL statement that uses "SELECT..." returns records that causes a run-time error.



2. Stored procedures that return records (or rows) require a Snapshot-type Recordset to capture the values. Listed below are two examples:

   Example 1

   The following example using a Data Control on a Visual Basic Form:
   

   
         Data1.Options = dbSQLPassThrough
         Data1.Recordsource = "sp_name"  ' Name of the stored procedure.
         Data1.Refresh   ' Refresh the data control.
    

   When you use the SQLPassThrough bit, the Microsoft Jet database engine ignores the syntax used and passes the command through to the SQL server.

   Example 2

   Using Data Access Objects:
   

   
         Dim Rs as Recordset
         ' Open your desired database here.
         Set MyDB = DBEngine.Workspaces(0).OpenDatabase(...
         Set Rs = MyDB.OpenRecordset("sp_name", dbOpenSnapshot, _
                  dbSQLPassThrough)
     

   You must use dbOpenSnapshot. dbOpenDynaset and dbOpenTable do not apply to pass-through queries.

   How to Pass Parameters to a Stored Procedure

   To pass parameters, include them after the name of the stored procedure in a string. For example:
   

   
         ' String specifying SQL.
         SQL = "My_StorProc parm1, parm2, parm3"
         ...
         ' For a stored procedure that doesn't return records.
         MyDb.Execute SQL, dbSQLPassThrough
         i = MyDb.RowsAffected
         ...
         'For a stored procedure that returns records.
         set Rs = MyDB.OpenRecordset(SQL, dbOpenSnapshot, dbSQLPassThrough)
     

   The object variable (Rs) contains the first set of results from the stored procedure (My_StorProc).

   Another Example

   The following contains more example code showing both methods:
   

   
         Dim db as Database
         Dim l as Long
         Dim Rs as Recordset
         Set Db = DBEngine.Workspaces(0).OpenDatabase _
         ("", False, False, "ODBC;dsn=yourdsn;uid=youruid;pwd=yourpwd:")
         ' For SPs that don't return rows.
         Db.Execute "YourSP_Name", dbSQLPassThrough
         l = Db.RowsAffected
         ' For SPs that return rows.
         Set Rs = Db.OpenRecordset("YourSP_Name", dbOpenSnapshot, _
   
          dbSQLPassThrough)
         Col1.text = Rs(0) ' Column one.
         Col2.text = Rs!ColumnName
         Col3.Text = Rs("ColumnName")
     

REFERENCES

For additional information about calling stored procedures, please see the following:

Microsoft SQL Server "Microsoft SQL Server Programmer's Reference for Visual Basic," version 4.2, pages 200-201

Additional query words: kbODBC kbVBp500 kbVBp600 kbVBp400 kbdse kbDSupport kbVBp

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Platform : WINDOWS
Issue type : kbhowto