CREATE TABLE ALPHA.USUARIOS ( NOMBRE VARCHAR (30) NOT NULL , APELLIDO VARCHAR (30) NOT NULL , ID_CIUDAD BIGINT NOT NULL , TELEFONO VARCHAR (15) NOT NULL , INTERNO VARCHAR (3) NOT NULL , APODO VARCHAR (10) NOT NULL , CLAVE VARCHAR (10) NOT NULL , EMAIL VARCHAR (20) NOT NULL , FECHANAC DATE NOT NULL , ID_USUARIO BIGINT NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 0, INCREMENT BY 1, NO CACHE ) , CONSTRAINT PK_USUARIO PRIMARY KEY ( ID_USUARIO) , CONSTRAINT FK_CIUDAD FOREIGN KEY (ID_CIUDAD) REFERENCES ALPHA.CIUDADES (ID_CIUDAD) ON DELETE RESTRICT ON UPDATE RESTRICT ENFORCED ENABLE QUERY OPTIMIZATION , CONSTRAINT EDADMAYOR21 CHECK (year((CURRENT DATE) - FECHANAC) >= 21) ENFORCED ENABLE QUERY OPTIMIZATION );