2.2.1. Domains

First, we define some domains that we will use in column definitions.

CREATE DOMAIN D_BOOLEAN AS
SMALLINT
CHECK (VALUE IN (0, 1));
COMMENT ON DOMAIN D_BOOLEAN IS
'Boolean type. 0 - FALSE, 1- TRUE';
CREATE DOMAIN D_MONEY AS
NUMERIC(15,2);
CREATE DOMAIN D_ZIPCODE AS
CHAR(10) CHARACTER SET UTF8
CHECK (TRIM(TRAILING FROM VALUE) SIMILAR TO '[0-9]+');
COMMENT ON DOMAIN D_ZIPCODE IS
'Zip code';

BOOLEAN Type

In Firebird 3.0, there is a native BOOLEAN type. Some drivers do not support it, due to its relatively recent appearance in Firebird’s SQL lexicon. With that in mind, our applications will be built on a database that will work with either Firebird 2.5 or Firebird 3.0.