ðÒÉ×ÅÔ CREATE DOMAIN IDUNIQUE AS INTEGER default 0 NOT NULL; CREATE TABLE CUSTOMER ( IDKEY IDUNIQUE, constraint pk_Customer primary key (idkey));
CREATE TABLE CASHPAPER ( IDKEY IDUNIQUE, IDCustomer integer, constraint pk_CASHPAPER primary key (idkey), constraint fk_CASHPAPER1 foreign key (IDCustomer) references Customer); IDCustomer ÄÏÌÖÎÏ ÂÙÔØ not null ÷ÒÏÄÅ ÒÁÎØÛÅ ÔÁËÏÅ ÎÅ ÐÒÏËÁÔÙ×ÁÌÏ, Á 2.0 ÂÅÚ ÐÒÏÂÌÅÍ. ñ ÞÔÏ-ÔÏ ÐÒÏÐÕÓÔÉÌ? äÍÉÔÒÉÊ