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SQL>
SQL> -- create demo table
SQL> create table Customer(
2 id NUMBER(3) primary key,
3 NAME VARCHAR2(15 BYTE)
4 )
5 /
Table created.
SQL>
SQL> create table account (
2 id NUMBER(3),
3 type VARCHAR2(20 BYTE)
4 )
5 /
Table created.
SQL>
SQL>
SQL> ALTER TABLE account
2 ADD CONSTRAINT fk
3 customerid REFERENCES customer(id) ON DELETE SET NULL;
Table altered.
SQL>
SQL>
SQL> drop table account;
Table dropped.
SQL>
SQL> drop table customer;
Table dropped.
SQL>
SQL>
SQL>SQL>
SQL>
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