Oracle 视图 ALL_TYPES 官方解释，作用，如何使用详细说明

Oracle视图ALL_TYPES是一个用户可获取的数据字典视图，用于显示当前用户可用的数据类型。每行表示当前用户有权访问的数据类型，该数据类型可以用于定义列和参数。

使用ALL_TYPES视图的一种最常见的用法就是查询一个指定的数据类型的详细信息：

SELECT * FROM ALL_TYPES WHERE TYPE_NAME=’VARCHAR2′;

执行上述查询将返回多行记录，其中包含有关VARCHAR2数据类型的更多详细信息，包括字节长度、最大长度等。

ALL_TYPES describes the object types accessible to the current user.

Related Views

DBA_TYPES describes all object types in the database.
USER_TYPES describes the object types owned by the current user. This view does not display the OWNER column.

Column	Datatype	Description
`OWNER`	`VARCHAR2(128)`	Owner of the type
`TYPE_NAME`	`VARCHAR2(128)`	Name of the type
`TYPE_OID`	`RAW(16)`	Object identifier (OID) of the type
`TYPECODE`	`VARCHAR2(128)`	Typecode of the type
`ATTRIBUTES`	`NUMBER`	Number of attributes (if any) in the type
`METHODS`	`NUMBER`	Number of methods (if any) in the type
`PREDEFINED`	`VARCHAR2(3)`	Indicates whether the type is a predefined type (`YES`) or not (`NO`)
`INCOMPLETE`	`VARCHAR2(3)`	Indicates whether the type is an incomplete type (`YES`) or not (`NO`)
`FINAL`	`VARCHAR2(3)`	Indicates whether the type is a final type (`YES`) or not (`NO`)
`INSTANTIABLE`	`VARCHAR2(3)`	Indicates whether the type is an instantiable type (`YES`) or not (`NO`)
`PERSISTABLE`	`VARCHAR2(3)`	Indicates whether the type is a persistable type (`YES`) or not (`NO`)
`SUPERTYPE_OWNER`	`VARCHAR2(128)`	Owner of the supertype (NULL if type is not a subtype)
`SUPERTYPE_NAME`	`VARCHAR2(128)`	Name of the supertype (NULL if type is not a subtype)
`LOCAL_ATTRIBUTES`	`NUMBER`	Number of local (not inherited) attributes (if any) in the subtype
`LOCAL_METHODS`	`NUMBER`	Number of local (not inherited) methods (if any) in the subtype
`TYPEID`	`RAW(16)`	Type ID value of the type