Definitions for "CHECK constraint"
CHECK integrity constraint on a column or set of columns requires that a specified condition be true or unknown for every row of the table. If a DML statement results in the condition of the CHECK constraint evaluating to false, then the statement is rolled back.
a mechanism for allowing predicates to be defined on a column
Specifies data values that are acceptable in a column. You can apply check constraints to multiple columns and you can apply multiple check constraints to a single column. When a table is deleted, all check constraints are also deleted.