CREATE DOMAIN(7) SQL Commands CREATE DOMAIN(7) NAME CREATE DOMAIN - SYNOPSIS CREATE DOMAIN name [AS] data_type [ DEFAULT expression ] [ constraint [ ... ] ] where constraint is: [ CONSTRAINT constraint_name ] { NOT NULL | NULL | CHECK (expression) } DESCRIPTION CREATE DOMAIN CREATE DOMAIN myschema.mydomain ... PARAMETERS name data_type DEFAULT expression DEFAULT CONSTRAINT constraint_name NOT NULL NULL NULL SQL CHECK (expression) CHECK VALUE CHECK VALUE EXAMPLES country_code CREATE DOMAIN country_code char(2) NOT NULL; CREATE TABLE countrylist (id integer, country country_code); COMPATIBILITY CREATE DOMAIN SQL SEE ALSO DROP DOMAIN [drop_domain(7)] Postgresql man man https://github.com/man-pages-zh/manpages- zh SQL - Language Statements 2003-11-02 CREATE DOMAIN(7)