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Check Constraints

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

Access

Access

Method

Ribbon

Design > Tools > Database Builder > Click on Table name > Constraints/Indexes > Right-click > Add New Constraint

Context Menu

In diagram | Right-click on Table | Features & Properties | Operations > Constraints/Indexes | Right-click | Add New Constraint

Keyboard Shortcuts

Click on Table: F9 > Constraints/Indexes: Ctrl+N

Create a Constraint

Step

Action

See also

1

On the 'Constraints/Indexes' 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

2

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

3

In the 'Properties' panel for the Condition property, type 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.

Notes

  • Any columns assigned to a check constraint are ignored