How to Add a Constraint in Access

Create a new table using VBA in Access.

Adding a constraint in Access is quite simple if you know a little about Visual Basic for Applications. VBA is a programming language used in Access and other Microsoft Office applications to automate routine tasks. A constraint is similar to an index. It helps you identify each row in a table with a unique value. A constraint can also be used to establish a relationship with other tables in your database.

Instructions

1. Launch Microsoft Access, click the "Database Tools," and click "Visual Basic" to launch the VB Editor window. Click the "Insert" menu and click "Module" to insert a new code module.

2. Type the following to start a new sub procedure:

   Private Sub createTableWithConstraint()

3. Copy and paste the following code to create a new table with three columns, one being a primary key constraint:

   DoCmd.RunSQL ("CREATE TABLE NewTable " _

   & "(FirstName CHAR, LastName CHAR, " _

   & "SSN INTEGER CONSTRAINT MyFieldConstraint " _

   & "PRIMARY KEY);")

4. End your sub procedure by typing "End Sub." Press "F5" to run the procedure.

References

• Microsoft: Constraint Clause (Microsoft Access SQL)