Question

我的表'MY_TABLE'有一个主键'CODE'，这个主键有几个引用它的外键约束，我需要暂时禁用它们。

尝试在此处扩展此答案：Fix ORA-02273: this unique/primary key is referenced by some foreign keys，但不包括constraint_name

我正在尝试选择所有引用'MY_TABLE''CODE'的foreign_key约束并禁用它们（最终启用，我假设您只是在语法中禁用enable for enable）

Answer 1

假设你有这样的表：

create table MY_TABLE ( CODE number primary key);
create table anotherTable ( code_ref number);
alter table  anotherTable add constraint ck1 foreign key ( code_ref) references my_table ( code);
create table yetAnotherTable ( code_ref number);
alter table  yetAnotherTable add constraint ck2 foreign key ( code_ref) references my_table ( code);

您可以使用类似以下内容来循环遍历引用表的给定列的所有约束，并使用以下命令禁用/启用它们：

begin
    for s in (
                SELECT 'alter table ' || c2.table_name || ' modify constraint ' || c2.constraint_name || ' disable' as statement
                FROM all_constraints c
                       INNER JOIN all_constraints c2
                         ON ( c.constraint_name = c2.r_constraint_name AND c.owner = c2.owner)
                       INNER JOIN all_cons_columns col
                         ON ( c.constraint_name = col.constraint_name AND c.owner = col.owner) 
                WHERE c2.constraint_type = 'R'
                  AND c.table_name = 'MY_TABLE'
                  AND c.owner = 'ALEK'
                  AND col.column_name = 'CODE'
             )
    loop
        dbms_output.put_line(s.statement);
        execute immediate s.statement;
    end loop;
end;

这给出（并执行）：

alter table YETANOTHERTABLE modify constraint CK2 disable
alter table ANOTHERTABLE modify constraint CK1 disable

Answer 2

尝试该查询以生成所需的所有更改：

SELECT  'alter table ' || table_name || ' disable constraint ' ||  constraint_name || ';' from (
  select distinct a.table_name, a.constraint_name
  FROM all_cons_columns a
  JOIN all_constraints c ON a.owner = c.owner
                    AND a.constraint_name = c.constraint_name
  JOIN all_constraints c_pk ON c.r_owner = c_pk.owner
                       AND c.r_constraint_name = c_pk.constraint_name
  WHERE c.constraint_type = 'R'
  AND c_pk.table_name = 'MY_TABLE');

Answer 3

您可以避免PL / SQL代码和几个动态构造的alter table语句。为了禁用依赖于特定表的主键的所有外键，只需使用cascade子句禁用主键，然后再次启用（如果需要）。

以下是一个例子：

--drop table t3;
--drop table t2;
--drop table t1;
create table t1(c1 number primary key);
create table t2(c1 number references t1(c1));
create table t3(c1 number references t1(c1));

select table_name
     , constraint_type
     , status
  from user_constraints
  where table_name in ('T1','T2', 'T3')

TABLE C STATUS    
----- - ----------
T2    R ENABLED   
T1    P ENABLED   
T3    R ENABLED   

3 rows selected.

禁用外键：

alter table t1 disable primary key cascade;
alter table t1 enable  primary key;

结果：

select table_name
     , constraint_type
     , status
  from user_constraints
  where table_name in ('T1','T2', 'T3')

TABLE C STATUS    
----- - ----------
T2    R DISABLED  
T1    P ENABLED   
T3    R DISABLED  

3 rows selected.

注意：在级联模式下无法再次启用所有外键约束。它必须手动完成。

Answer 4

您必须将表的名称放入

select 'alter table '||table_name||' disable constraint '|| constraint_name||'; 'from user_constraint
where r_constraint_name in
(select constraint_name
    from user_constraints
    where table_name='TCLIENTSALBARANS'
    and constraint_type='P');

禁用与特定表关联的所有外键约束

4 个答案: