问题描述
|
我想尝试几天来禁用所有表的约束,插入数据并启用约束。它可以工作,但是我做了一些测试,当我插入不尊重外键的行时,启用约束时没有错误消息。我所看到的是该约束未得到验证。
这是要禁用的代码
begin
BEGIN
FOR rec IN ( SELECT constraint_name,table_name FROM user_constraints WHERE constraint_type = \'R\' OR constraint_type = \'P\' )
LOOP
BEGIN
EXECUTE IMMEDIATE \'alter table \'||rec.table_name||\' disable constraint \'||rec.constraint_name;
EXCEPTION WHEN OTHERS THEN
dbms_output.put_line( \'ERROR: alter table \'||rec.table_name||\' disABLE constraint \'||rec.constraint_name||\';\' );
END;
END LOOP;
DBMS_OUTPUT.PUT_LINE(\'CONSTRAINTS disABLED\');
END;
BEGIN
FOR rec IN ( SELECT trigger_name FROM user_triggers WHERE TRIGGER_NAME NOT LIKE \'BIN$%\' )
LOOP
EXECUTE IMMEDIATE \'alter trigger \'||rec.trigger_name||\' disable\';
END LOOP;
END;
DBMS_OUTPUT.PUT_LINE(\'TRIGGERS disABLED\');
end;
/
这是启用的代码
begin
BEGIN
FOR rec IN ( SELECT constraint_name,table_name FROM user_constraints where status = \'disABLED\' and constraint_type = \'R\' OR constraint_type = \'P\' )
LOOP
BEGIN
EXECUTE IMMEDIATE \'alter table \'||rec.table_name||\' enable constraint \'||rec.constraint_name;
dbms_output.put_line(\'alter table \'||rec.table_name||\' enable constraint \'||rec.constraint_name);
EXCEPTION
WHEN OTHERS THEN
dbms_output.put_line(\'ERROR: alter table \'||rec.table_name||\' enable constraint \'||rec.constraint_name||\' ;\' );
END;
END LOOP;
END;
DBMS_OUTPUT.PUT_LINE(\'CONSTRAINTS ENABLED\');
BEGIN
FOR rec IN ( SELECT trigger_name FROM user_triggers WHERE TRIGGER_NAME NOT LIKE \'BIN$%\' )
LOOP
EXECUTE IMMEDIATE \'alter trigger \'||rec.trigger_name||\' enable\';
END LOOP;
END;
DBMS_OUTPUT.PUT_LINE(\'TRIGGERS ENABLED\');
END;
我不知道如何最后检查所有约束并在不起作用时进行回滚。
解决方法
首先,您的代码捕获了无法启用约束时引发的错误,并且抛出该错误而不是重新引发该错误。那几乎总是一个错误。如果您不想忽略启用约束失败的事实,则需要类似
FOR rec IN ( SELECT constraint_name,table_name
FROM user_constraints
where status = \'DISABLED\'
and constraint_type = \'R\'
OR constraint_type = \'P\' )
LOOP
BEGIN
l_sql_stmt := \'alter table \'||rec.table_name||
\' enable constraint \' || rec.constraint_name;
dbms_output.put_line( l_sql_stmt );
EXECUTE IMMEDIATE l_sql_stmt;
EXCEPTION
WHEN OTHERS THEN
dbms_output.put_line(\'ERROR: \' || l_sql_stmt );
raise; -- re-raise the exception
END;
END LOOP;
由于ALTER TABLE是DDL,因此无法回滚。如果在启用一个约束时遇到错误,则无法回滚所有先前约束的启用。
根据您的最新更新,听起来您可能根本不想禁用和启用约束。您可能只想创建可延迟的约束。
SQL> create table foo (
2 col1 number
3 );
Table created.
SQL> ed
Wrote file afiedt.buf
1 alter table foo
2 add constraint pk_foo
3 primary key( col1 )
4* deferrable
SQL> /
Table altered.
通常,它的行为类似于任何其他主键约束
SQL> insert into foo values( 1 );
1 row created.
SQL> insert into foo values( 1 );
insert into foo values( 1 )
*
ERROR at line 1:
ORA-00001: unique constraint (SCOTT.PK_FOO) violated
SQL> rollback;
Rollback complete.
但是,如果您推迟约束,则直到您提交该约束,该约束才会被验证。并且,如果在事务结束时违反了约束,则事务将回滚。
SQL> alter session set constraints = deferred;
Session altered.
SQL> select * from foo;
no rows selected
SQL> insert into foo values( 1 );
1 row created.
SQL> insert into foo values( 1 );
1 row created.
SQL> insert into foo values( 1 );
1 row created.
SQL> commit;
commit
*
ERROR at line 1:
ORA-02091: transaction rolled back
ORA-00001: unique constraint (SCOTT.PK_FOO) violated