Check Dialog

Use the Check dialog to define or modify a check constraint. A check constraint specifies an expression that produces a Boolean result that new or updated rows must satisfy for an insert or update operation to succeed.

The Check dialog organizes the development of a check constraint through the General and Definition tabs. The SQL tab displays the SQL code generated by dialog selections.

Check dialog general tab

Create Check dialog - General tab

Use the fields in the General tab to identify the check constraint:

  • Use the Name field to provide a descriptive name for the check constraint that will be displayed in the Browser tree control. With PostgreSQL 9.5 forward, when a table has multiple check constraints, they will be tested for each row in alphabetical order by name and after NOT NULL constraints.

  • Store notes about the check constraint in the Comment field.

Click the Definition tab to continue.

Check dialog definition tab

Create Check dialog - Definition tab

Use the fields in the Definition tab to define the check constraint:

  • Provide the expression that a row must satisfy in the Check field.

  • Move the No Inherit? switch to the Yes position to specify this constraint is automatically inherited by a table’s children. The default is No.

  • Move the Don't validate? switch to the No position to skip validation of existing data; the constraint may not hold for all rows in the table. The default is Yes.

Click the SQL tab to continue.

Your entries in the Check dialog generate a SQL command (see an example below). Use the SQL tab for review; revisit or switch tabs to make any changes to the SQL command.

Example

The following is an example of the sql command generated by user selections in the Check dialog:

Check dialog sql tab

Create Check dialog - SQL tab

The example shown demonstrates creating a check constraint named check_price on the price column of the products table. The constraint confirms that any values added to the column are greater than 0.

  • Click the Info button (i) to access online help. View context-sensitive help in the Tabbed browser, where a new tab displays the PostgreSQL core documentation.

  • Click the Save button to save work.

  • Click the Cancel button to exit without saving work.

  • Click the Reset button to restore configuration parameters.