How To Create a Table with Primary Key Through ADOX

ADOX is an extension to ActiveX Data Objects that allows the manipulation of the database schema. This article illustrates how to use ADOX to create a table and add a Primary Key.

NOTE: Not all OLE DB providers support the interfaces required to support ADOX methods. With those providers, you have to use Data Definition Queries or another object model to manipulate the database schema.

The first procedure in the example below creates a new table in an existing Microsoft Access database, creates a new field in that table, then creates a primary key index. When adding a single-field primary key, you do not need to use the ADOX Key object.

The second procedure utilizes the ADOX Key object to add a multiple field key to a table.

Steps to Create the Sample Application

1. In Microsoft Visual Basic 5.0 or 6.0, create a new Standard EXE project. Form1 is created by default.
2. On the Project menu, select References to add the following type libraries:
   Microsoft ActiveX Data Objects 2.1 Library
   Microsoft ADO Ext. 2.1 for DDL and Security
3. Add two Command buttons (Command1 and Command2) and the following code to the Form1:

   Option Explicit
   
   Private Sub Command1_Click()
   '
   ' This code adds a single-field Primary key
   '
   Dim Cn As ADODB.Connection, Cat As ADOX.Catalog, objTable As ADOX.Table
   
    Set Cn = New ADODB.Connection
    Set Cat = New ADOX.Catalog
    Set objTable = New ADOX.Table
   
    'Open the connection
    Cn.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=biblio.mdb"
     
    'Open the Catalog
    Set Cat.ActiveConnection = Cn
   
    'Create the table
    objTable.Name = "Test_Table"
     
    'Create and Append a new field to the "Test_Table" Columns Collection
    objTable.Columns.Append "PrimaryKey_Field", adInteger
     
    'Create and Append a new key. Note that we are merely passing
    'the "PimaryKey_Field" column as the source of the primary key. This
    'new Key will be Appended to the Keys Collection of "Test_Table"
    objTable.Keys.Append "PrimaryKey", adKeyPrimary, "PrimaryKey_Field"
   
    'Append the newly created table to the Tables Collection
    Cat.Tables.Append objTable
   
   ' clean up objects
    Set objKey = Nothing
    Set objTable = Nothing
    Set Cat = Nothing
    Cn.Close
    Set Cn = Nothing
   End Sub
   
   Private Sub Command2_Click()
   '
   ' This code adds a multi-field Primary Key
   '
   Dim Cn As ADODB.Connection, Cat As ADOX.Catalog
   Dim objTable As ADOX.Table, objKey As ADOX.Key
   
    Set Cn = New ADODB.Connection
    Set Cat = New ADOX.Catalog
    Set objTable = New ADOX.Table
    Set objKey = New ADOX.Key
   
    Cn.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=biblio.mdb"
    Set Cat.ActiveConnection = Cn
    objTable.Name = "Test_Table2"
   
    objTable.Columns.Append "PrimaryKey_Field1", adInteger
    objTable.Columns.Append "PrimaryKey_Field2", adInteger
     
    objKey.Name = "PrimaryKey"
    objKey.Type = adKeyPrimary
    objKey.Columns.Append "PrimaryKey_Field1"
    objKey.Columns.Append "PrimaryKey_Field2"
   
    objTable.Keys.Append objKey
   
    Cat.Tables.Append objTable
   
   ' clean up objects
    Set objKey = Nothing
    Set objTable = Nothing
    Set Cat = Nothing
    Cn.Close
    Set Cn = Nothing
   End Sub
         

   NOTE: You might have to adjust the connect string to point to a valid Jet database.
4. Run the application and click the Command buttons. You can check the table definitions for Test_Table and TestTable2 in Microsoft Access 97, Microsoft Access 2000, or the Visual Basic Visual Data Manager add-in