identifying关系是说子表的主键列包含了外键列,一般是自己的主键包括几个列
拿表INVENTORY_LEVELS来说。
ALTER TABLE "GOSALES"."INVENTORY_LEVELS"
ADD PRIMARY KEY
("INVENTORY_YEAR", "INVENTORY_MONTH", "WAREHOUSE_BRANCH_CODE", "PRODUCT_NUMBER");
ALTER TABLE "GOSALES"."INVENTORY_LEVELS"
ADD CONSTRAINT "FK_2137930838" FOREIGN KEY
("PRODUCT_NUMBER")
REFERENCES "GOSALES"."PRODUCT"
("PRODUCT_NUMBER")
ON DELETE NO ACTION
ON UPDATE NO ACTION
ENFORCED
ENABLE QUERY OPTIMIZATION;
ALTER TABLE "GOSALES"."INVENTORY_LEVELS"
ADD CONSTRAINT "FK_2121930781" FOREIGN KEY
("WAREHOUSE_BRANCH_CODE")
REFERENCES "GOSALES"."BRANCH"
("BRANCH_CODE")
ON DELETE NO ACTION
ON UPDATE NO ACTION
ENFORCED
ENABLE QUERY OPTIMIZATION;
最重要的一点是这样的:
要注意这种关系的表达使用的线是不一样的
带圆圈的那个是子表,另外一端是附表,做图的时候是从父表拉线到字表。