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The Oracle Database contains tables which describe what database objects – i.e. tables, procedures, triggers etc. – exist within the database. This information about the information is known as metadata. Oracle metadata is information contained within the Oracle Database about the objects contained within the Oracle database. You can use this information to find all tables accessible by a user, get a list of stored procedures, and get information about many other types of objects in an Oracle database. The ORACLE application server and Oracle relational database keep metadata in two areas: data dictionary tables (accessed via built-in views) and a metadata registry. ==Views for metadata== The total number of these views depends on the Oracle version, but is in a 1000 range. The main built-in views accessing Oracle RDBMS data dictionary tables are few, and are as follows: * ALL_TABLES – list of all tables in the current database that are accessible to the current user * ALL_VIEWS – list of all views in the current database that are accessible to the current user * ALL_TAB_COLUMNS – list of all columns in the database that are accessible to the current user * ALL_ARGUMENTS – lists the arguments of functions and procedures that are accessible to the current user * ALL_ERRORS – lists descriptions of errors on all stored objects (views, procedures, functions, packages, and package bodies) that are accessible to the current user * ALL_OBJECT_SIZE – included for backward compatibility with Oracle version 5 * ALL_PROCEDURES – (from Oracle 9 onwards) lists all functions and procedures (along with associated properties) that are accessible to the current user * ALL_SOURCE – describes the text (i.e. PL/SQL) source of the stored objects accessible to the current user In addition there are equivalent views prefixed "USER_" which show only the objects owned by the current user (i.e. a more restricted view of metadata) and prefixed "DBA_" which show all objects in the database (i.e. an unrestricted global view of metadata for the database instance). Naturally the access to "DBA_" metadata views requires specific privileges. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Oracle metadata」の詳細全文を読む スポンサード リンク
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