Oracle教程 2023-02-25

Oracle 视图 ALL_NESTED_TABLES 官方解释，作用，如何使用详细说明

Oracle视图ALL_NESTED_TABLES是Oracle视图中的一个用于显示用户可以访问的嵌套表（即外部表）的视图。此视图中提供了嵌套表的结构信息，如表名，表空间名，字段列表，字段数据类型和长度等。

为了使用ALL_NESTED_TABLES视图，用户可以执行以下SELECT语句：

SELECT TABLE_NAME,
TABLESPACE_NAME,
COLUMN_NAME,
DATA_TYPE,
DATA_LENGTH
FROM ALL_NESTED_TABLES
WHERE OWNER = ‘USER_NAME’;

或者

SELECT *
FROM ALL_NESTED_TABLES
WHERE OWNER = ‘USER_NAME’;

这些语句将返回满足给定的条件的嵌套表的信息。

ALL_NESTED_TABLES视图可用于提供用户可访问的嵌套表的信息，并允许用户将查询的内容限制为特定的表或特定的表空间，从而显示可用的表和每个表的定义。该视图也可用于帮助开发人员检查对象的命名规则。

ALL_NESTED_TABLES describes the nested tables in tables accessible to the current user.

Related Views

DBA_NESTED_TABLES describes all nested tables in the database.
USER_NESTED_TABLES describes nested tables owned by the current user. This view does not display the OWNER column.

Column	Datatype	Description
`OWNER`	`VARCHAR2(128)`	Owner of the nested table
`TABLE_NAME`	`VARCHAR2(128)`	Name of the nested table
`TABLE_TYPE_OWNER`	`VARCHAR2(128)`	Owner of the type of which the nested table was created
`TABLE_TYPE_NAME`	`VARCHAR2(128)`	Name of the type of the nested table
`PARENT_TABLE_NAME`	`VARCHAR2(128)`	Name of the parent table containing the nested table
`PARENT_TABLE_COLUMN`	`VARCHAR2(4000)`	Column name of the parent table that corresponds to the nested table
`STORAGE_SPEC`	`VARCHAR2(30)`	Indicates whether storage for the nested table is `USER_SPECIFIED` or `DEFAULT`
`RETURN_TYPE`	`VARCHAR2(20)`	Return type of the varray column (`LOCATOR`) or (`VALUE`)
`ELEMENT_SUBSTITUTABLE`	`VARCHAR2(25)`	Indicates whether the nested table element is substitutable (`Y`) or not (`N`)