ORA-02266: unique/primary keys in table referenced by enabled foreign keys

在数据库里面使用TRUNCATE命令截断一个表的数据时，遇到如下错误

SQL >TRUNCATE TABLE ESCMOWNER.SUBX_ITEM

ORA-02266: unique/primary keys in table referenced by enabled foreign keys

有时候对应的中文错误提示为：ORA-02266: 表中的唯一/主键被启用的外部关键字引用，一般出现这个错误，是因为表中的主键被其它表的外键所引用，导致删除数据时出错。

此时，你可以通过下面脚本查看一下涉及该表主键的外键约束信息。

   1: select c1.table_name      as org_table_name,

   2:        c1.constraint_name as org_constraint_name,

   3:        c1.constraint_type as org_constriant_type,

   4:        n1.column_name     as org_colun_name,

   5:        c2.table_name      as ref_table_name,

   6:        c2.constraint_type as ref_constraint_type,

   7:        c2.constraint_name as ref_constraint_name,

   8:        n2.column_name     as ref_column_name

   9:   from dba_constraints  c1,

  10:        dba_constraints  c2,

  11:        dba_cons_columns n1,

  12:        dba_cons_columns n2

  13:  where c1.owner = 'OWNER_NAME'

  14:    and c1.table_name = 'TABLE_NAME'

  15:    and n1.constraint_name = c1.constraint_name

  16:    and n1.owner = c1.owner

  17:    and c2.constraint_type = 'R'

  18:    and c2.r_constraint_name = c1.constraint_name

  19:    and n2.owner = c2.owner

  20:    and n2.constraint_name = c2.constraint_name;

查询结果如下所示：

   1: SQL> select c1.table_name      as org_table_name,

   2:   2         c1.constraint_name as org_constraint_name,

   3:   3         c1.constraint_type as org_constriant_type,

   4:   4         n1.column_name     as org_colun_name,

   5:   5         c2.table_name      as ref_table_name,

   6:   6         c2.constraint_type as ref_constraint_type,

   7:   7         c2.constraint_name as ref_constraint_name,

   8:   8         n2.column_name     as ref_column_name

   9:   9    from dba_constraints  c1,

  10:  10         dba_constraints  c2,

  11:  11         dba_cons_columns n1,

  12:  12         dba_cons_columns n2

  13:  13   where c1.owner = 'ESCMOWNER'

  14:  14     and c1.table_name = 'SUBX_ITEM'

  15:  15     and n1.constraint_name = c1.constraint_name

  16:  16     and n1.owner = c1.owner

  17:  17     and c2.constraint_type = 'R'

  18:  18     and c2.r_constraint_name = c1.constraint_name

  19:  19     and n2.owner = c2.owner

  20:  20     and n2.constraint_name = c2.constraint_name;

  21:  

  22: ORG_TABLE_NAME   ORG_CONSTRAINT_NAME  ORG_CONSTRIANT_TYPE ORG_COLUN_NAME  REF_TABLE_NAME  REF_CONSTRAINT_TYPE REF_CONSTRAINT_NAME REF_COLUMN_NAME        

  23: --------------   ------------------- ------------------- ---------------- --------------  ------------------- ------------------- 

  24: SUBX_ITEM             PK_SUBX_ITEM           P               ITEM_ID         SUBX_DIMM            R                   FK_SUBX_DIMM                   ITEM_ID

  25:  

  26: SQL>

解决方法：先禁用表的主键约束，等截断后再启用

   1: SQL> ALTER TABLE ESCMOWNER.SUBX_ITEM DISABLE PRIMARY KEY CASCADE;

   2:  

   3:  

   4: SQL>TRUNCATE TABLE ESCMOWNER.SUBX_ITEM

   5:  

   6: SQL>ALTER TABLE ESCMOWNER.SUBX_ITEM ENABLE PRIMARY KEY;

   7:  

   8: SQL>ALTER TABLE ESCMOWNER.SUBX_DIMM ENABLE CONSTRAINT FK_SUBX_DIMM;

   9:  

注意事项：在ENABLE主键后不会自动恢复外键（没有cascade选项），因此需要手工对引用该键的约束进行ENABLE。