A table constraint is a named check that enforces data requirements of check parameters.
Whenever you place a data restriction on a table, a constraint is created automatically. You have the option of specifying a name for the constraint. If you do not, the database creates a default constraint name automatically.
This name helps you to identify and customize a table constraint in scripts for database creation and modification.
For more information, see Check Parameters (CDM/LDM/PDM).