Database 插入到Oracle同义词

如果我有另一个模式的表的同义词，我可以插入同义词吗？

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如果是这样，它还会影响原始表吗？

同义词不是真正的对象，只是指向对象的指针；所以，无论你对同义词做什么，你都是在引用的对象上做的

通过显式写入模式，可以访问不同模式中的表：

SQL> select count(1) from sys.sys_table;

  COUNT(1)
----------
         0

SQL> select count(1) from sys_table;
select count(1) from sys_table
                     *
ERROR at line 1:
ORA-00942: table or view does not exist

创建同义词

SQL> create synonym my_synonym for sys.sys_table;

Synonym created.

然后可以使用同义词访问该表：

SQL> select count(1) from my_synonym;

  COUNT(1)
----------
         0

SQL> select count(1) from sys_table;
select count(1) from sys_table
                     *
ERROR at line 1:
ORA-00942: table or view does not exist

但您仍然无法直接访问该表：

SQL> select count(1) from my_synonym;

  COUNT(1)
----------
         0

SQL> select count(1) from sys_table;
select count(1) from sys_table
                     *
ERROR at line 1:
ORA-00942: table or view does not exist

您可以使用同义词插入到表中

SQL> insert into my_synonym values (1);

1 row created.

SQL> drop synonym my_synonym;

Synonym dropped.

SQL> select count(1) from my_synonym;

    select count(1) from my_synonym
                         *
    ERROR at line 1:
    ORA-00942: table or view does not exist

。。。或使用schema.table：

无论您如何操作，都会插入所有行：

SQL> select count(1) from sys.sys_table;

  COUNT(1)
----------
         2

SQL> select count(1) from my_synonym;

  COUNT(1)
----------
         2

如果你放弃同义词

SQL> insert into my_synonym values (1);

1 row created.

SQL> drop synonym my_synonym;

Synonym dropped.

SQL> select count(1) from my_synonym;

    select count(1) from my_synonym
                         *
    ERROR at line 1:
    ORA-00942: table or view does not exist

您需要使用schema.table，数据和表仍然保留：

SQL> select count(1) from sys.sys_table;

  COUNT(1)
----------
         2

但是，当然，你不能再使用同义词了

SQL> insert into my_synonym values (1);

1 row created.

SQL> drop synonym my_synonym;

Synonym dropped.

SQL> select count(1) from my_synonym;

    select count(1) from my_synonym
                         *
    ERROR at line 1:
    ORA-00942: table or view does not exist

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同义词只是指向对象的指针。因此，您可以在SQL代码中将其视为本地对象，对其执行的任何DML操作都将在指向的对象上执行。