39.9. check_constraints
 The view check_constraints contains all check constraints, either defined on a table or on a domain, that are owned by a currently enabled role. (The owner of the table or domain is the owner of the constraint.) 
Table 39.7. check_constraints Columns
Column Type Description  | 
|---|
 Name of the database containing the constraint (always the current database)  | 
 Name of the schema containing the constraint  | 
 Name of the constraint  | 
 The check expression of the check constraint  |