创建两个表：JILIAN_P,JILIAN_C。JILIAN_P为主表，JILIAN_C为从表。
CREATE TABLE JILIAN_P (
"P_ID" VARCHAR2(10) NOT NULL,
"P_NAME" VARCHAR2(10) NOT NULL, PRIMARY KEY("P_ID")) ;
CREATE TABLE "SCOTT"."JILIAN_C" (
"C_ID" VARCHAR2(10) NOT NULL,
"C_JOB" VARCHAR2(10) NOT NULL, "C_SAL" VARCHAR2(10) NOT NULL,
PRIMARY KEY("C_ID"), FOREIGN KEY("C_ID")
REFERENCES "SCOTT"."JILIAN_P"("P_ID")
ON DELETE CASCADE) ;
其中，JILIAN_P表中设P_ID为主键，JILIAN_C表中，设C_ID为主键及外键，引用JILIAN_P中的P_ID，并设置外键级联。
此时，若删除JILIAN_P中的数据，则JILIAN_C中C_ID与JILIAN_P中P_ID相同的数据也同时被删除。这是级联的效果。