Managing checks
Check specifies an expression producing a Boolean result which new or updated rows must satisfy for an insert or update operation to succeed. Expressions evaluating to TRUE or UNKNOWN succeed. Should any row of an insert or update operation produce a FALSE result an error exception is raised and the insert or update does not alter the database. A check constraint specified as a column constraint should reference that column's value only, while an expression appearing in a table constraint may reference multiple columns.
Table checks are managed on the Checks tab of the Table Editor.
To add a check to the table:
- Open the table in the Table Editor.
- Open the Constaraints tab then choose the Checks tab.
- Right-click and select the Add Check... item from the popup menu.
- Edit check properties within the Check Editor dialog.
To edit check:
- Open the table in the Table Editor.
- Open the Constaraints tab then choose the Checks tab.
- Right-click the check and select the Edit Check item from the popup menu or simply double-click the key to edit.
- Edit check properties within the Check Editor Dialog.
To drop the check:
- Open the table in the Table Editor.
- Open the Constaraints tab then choose the Checks tab.
- Right-click the key to drop and select the Drop Check item from the popup menu.
- Confirm dropping in the dialog window.
