ERROR Column Constraint
Column constraint to define an error message to be displayed when a validation check fails
ALTER TABLE, CONSTRAINTS, CREATE TABLE
A constraint is used to define rules that help to provide data integrity. Column constraints are specific to the column name specified. You must have ALTER privilege on the table. The table will be locked for EXCLUSIVE use during the operation.
The ERROR column constraint is used to define an error message to be displayed when a validation check fails. The <expC> is a character string of up to 80 characters.
ALTER TABLE customer; ADD COLUMN timeref CHAR(8); CHECK validtime(timeref); ERROR "Not a valid time string"
Lianja, Lianja Server