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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.
Use the fields in the General tab to identify the check constraint:
Click the Definition tab to continue.
Use the fields in the Definition tab to define the check constraint:
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.
The following is an example of the sql command generated by user selections in the Check dialog:
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.