CREATE TABLE tb_cabcin (
NroDocCCI CHAR(6),
CodEnt int,
FecEmiCCI Date,
CodCli int,
ImpTotCCI Decimal(8,2),
PRIMARY KEY (NroDocCCI, CodEnt),
FOREIGN KEY (CodEnt) references tb_ent(CodEnt),
FOREIGN KEY (CodCli) references tb_cli(CodCli)
);

CREATE TABLE tb_detcin (
CodDCI serial,
NroDocCCI CHAR(6),
CodEnt int,
CodPrd int,
PsoDCI Decimal(8,2),
PreDCI Decimal(8,2),
ImpDCI Decimal(8,2),
CntItm int,
ObsDCI text,
PRIMARY KEY (CodDCI, NroDocCCI, CodEnt),
FOREIGN KEY (NroDocCCI, CodEnt)
  references tb_cabcin(NroDocCCI, CodEnt) ON DELETE CASCADE ON UPDATE CASCADE,
FOREIGN KEY (CodPrd) references tb_prd(CodPrd)
);