REMOVER_CONSTRAINT(T, 'FOREIGN KEY');

REMOVER_CONSTRAINT(T, 'CHECK);

create procedure REMOVER_CONSTRAINT (
    TABELA varchar(50),
    TIPO_CONSTRAINT varchar(50))
as
declare variable SQL varchar(100);
begin
  SELECT
    'ALTER TABLE ' || TRIM(RC.RDB$RELATION_NAME) ||
    ' DROP CONSTRAINT ' || TRIM(RC.RDB$CONSTRAINT_NAME) || ';'
  FROM RDB$RELATION_CONSTRAINTS RC
  WHERE RC.RDB$CONSTRAINT_TYPE = :TIPO_CONSTRAINT
        AND RDB$RELATION_NAME  = :TABELA
  INTO :V_CONSTRAINT;

  EXECUTE STATEMENT :SQL ;
end