CREATE DOMAIN quantity NUMBER( 7 ) check (quantity >  0 );

CREATE DOMAIN gender CHAR( 1 ) check (gender IN ('М', 'Ж'));

CREATE DOMAIN short_name VARCHAR2( 25 );

CREATE DOMAIN long_name VARCHAR2( 249 );

CREATE DOMAIN birth_date DATE CHECK (birth_date >= TO_DATE('01.01.1900', 'DD.MM.YYYY'));

CREATE DOMAIN id NUMBER( 10 );

CREATE TABLE emp(
   empno id
      CONSTRAINT emp#p PRIMARY KEY
 , ename short_name      NOT NULL
 , birth_date birth_date NOT NULL
 , gender                NOT NULL
 , deptno id             NOT NULL
 , child_cnt quantity
   );

CREATE TABLE dict(
   dict_id id
       CONSTRAINT dict#p PRIMARY KEY
 , name short_name NOT NULL
 , descr long_name
   );

...
ALTER DOMAIN short_name VARCHAR2( 32 );

ALTER DOMAIN quantity NUMBER( 10 );

ALTER DOMAIN id NUMBER( 12 );
...