declare
    column_exists exception;
    pragma exception_init (column_exists , -01430);
begin
    execute immediate 'ALTER TABLE ESTADO_CIVIL MODIFY (ESTADOCIVIL_ID NOT NULL)';
    execute immediate 'ALTER TABLE ESTADO_CIVIL ADD CONSTRAINT ESTADO_CIVIL_PK PRIMARY KEY (ESTADOCIVIL_ID) ENABLE';
    exception when others then null;
end;