Check Constraints

A Check Constraint enforces domain integrity by limiting the values that are accepted by a column.

Access Tools | Database Builder | Click on Table name > Constraints | Right-click | Add New Constraint (Ctrl+N)

In diagram or Project Browser | Right-click on Table | Features & Properties | Operations > Constraint | Add New Constraint (Ctrl+N)

Create a Constraint



See also


On the 'Constraint' tab of the Columns and Constraints screen, a new constraint is automatically created and assigned the default constraint name and a 'Type' of index.

Overtype the constraint name with a name that identifies the constraint as a check constraint, such as 'CHK_ColumnName' (the CHK_ prefix is optional).

Database Table Constraints


In the 'Type' field, change the value from 'index' to 'check'.


In Properties panel, for the Condition property type in the SQL statement that will be used as the Check Condition; for example, column1 < 1000.

If the condition is long, click on the button to display a SQL editor (with syntax highlighting).

Delete a Check Constraint

If you do not want to keep a check constraint, either:

  • Right-click on it in the list and select Delete constraint '<name>', or
  • Click on the item and press Ctrl+D

The constraint is immediately deleted.

Learning Center topics

  • Alt+F1 | Enterprise Architect | Database Engineering | Physical Data Model | Check Constraint