Oracle PL/SQL/Constraints/DELETE CASCADE — различия между версиями
Admin (обсуждение | вклад) м (1 версия) |
(нет различий)
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Текущая версия на 10:01, 26 мая 2010
Create a foreign key with a cascade delete with more than one field
SQL> -- create a foreign key with a cascade delete with more than one field
SQL>
SQL> CREATE TABLE supplier
2 ( supplier_id numeric(10) not null,
3 supplier_name varchar2(50) not null,
4 contact_name varchar2(50),
5 CONSTRAINT supplier_pk PRIMARY KEY (supplier_id, supplier_name)
6 );
Table created.
SQL>
SQL>
SQL> CREATE TABLE products
2 ( product_id numeric(10) not null,
3 supplier_id numeric(10) not null,
4 supplier_name varchar2(50) not null,
5 CONSTRAINT fk_supplier_comp
6 FOREIGN KEY (supplier_id, supplier_name)
7 REFERENCES supplier(supplier_id, supplier_name)
8 ON DELETE CASCADE
9 );
Table created.
SQL>
SQL> desc products;
Name Null? Type
----------------------------------------------------------------------------------------------------- -------- --------------------------------------------------------------------
PRODUCT_ID NOT NULL NUMBER(10)
SUPPLIER_ID NOT NULL NUMBER(10)
SUPPLIER_NAME NOT NULL VARCHAR2(50)
SQL> desc supplier;
Name Null? Type
----------------------------------------------------------------------------------------------------- -------- --------------------------------------------------------------------
SUPPLIER_ID NOT NULL NUMBER(10)
SUPPLIER_NAME NOT NULL VARCHAR2(50)
CONTACT_NAME VARCHAR2(50)
SQL>
SQL> drop table products cascade constraints;
Table dropped.
SQL>
SQL> drop table supplier cascade constraints;
Table dropped.
SQL>