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Oracle® Database Administrator's Guide
11g Release 2 (11.2)

Part Number E25494-02
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PDF · Mobi · ePub

Tables Data Dictionary Views

The following views allow you to access information about tables.

View Description
DBA_TABLES

ALL_TABLES

USER_TABLES

DBA view describes all relational tables in the database. ALL view describes all tables accessible to the user. USER view is restricted to tables owned by the user. Some columns in these views contain statistics that are generated by the DBMS_STATS package or ANALYZE statement.
DBA_TAB_COLUMNS

ALL_TAB_COLUMNS

USER_TAB_COLUMNS

These views describe the columns of tables, views, and clusters in the database. Some columns in these views contain statistics that are generated by the DBMS_STATS package or ANALYZE statement.
DBA_ALL_TABLES

ALL_ALL_TABLES

USER_ALL_TABLES

These views describe all relational and object tables in the database. Object tables are not specifically discussed in this book.
DBA_TAB_COMMENTS

ALL_TAB_COMMENTS

USER_TAB_COMMENTS

These views display comments for tables and views. Comments are entered using the COMMENT statement.
DBA_COL_COMMENTS

ALL_COL_COMMENTS

USER_COL_COMMENTS

These views display comments for table and view columns. Comments are entered using the COMMENT statement.
DBA_EXTERNAL_TABLES

ALL_EXTERNAL_TABLES

USER_EXTERNAL_TABLES

These views list the specific attributes of external tables in the database.
DBA_EXTERNAL_LOCATIONS

ALL_EXTERNAL_LOCATIONS

USER_EXTERNAL_LOCATIONS

These views list the data sources for external tables.
DBA_TAB_HISTOGRAMS

ALL_TAB_HISTOGRAMS

USER_TAB_HISTOGRAMS

These views describe histograms on tables and views.
DBA_TAB_STATISTICS

ALL_TAB_STATISTICS

USER_TAB_STATISTICS

These views contain optimizer statistics for tables.
DBA_TAB_COL_STATISTICS

ALL_TAB_COL_STATISTICS

USER_TAB_COL_STATISTICS

These views provide column statistics and histogram information extracted from the related TAB_COLUMNS views.
DBA_TAB_MODIFICATIONS

ALL_TAB_MODIFICATIONS

USER_TAB_MODIFICATIONS

These views describe tables that have been modified since the last time table statistics were gathered on them. They are not populated immediately, but after a time lapse (usually 3 hours).
DBA_ENCRYPTED_COLUMNS

USER_ENCRYPTED_COLUMNS

ALL_ENCRYPTED_COLUMNS

These views list table columns that are encrypted, and for each column, lists the encryption algorithm in use.
DBA_UNUSED_COL_TABS

ALL_UNUSED_COL_TABS

USER_UNUSED_COL_TABS

These views list tables with unused columns, as marked by the ALTER TABLE ... SET UNUSED statement.
DBA_PARTIAL_DROP_TABS

ALL_PARTIAL_DROP_TABS

USER_PARTIAL_DROP_TABS

These views list tables that have partially completed DROP COLUMN operations. These operations could be incomplete because the operation was interrupted by the user or a system failure.

Example: Displaying Column Information

Column information, such as name, data type, length, precision, scale, and default data values can be listed using one of the views ending with the _COLUMNS suffix. For example, the following query lists all of the default column values for the emp and dept tables:

SELECT TABLE_NAME, COLUMN_NAME, DATA_TYPE, DATA_LENGTH, LAST_ANALYZED
    FROM DBA_TAB_COLUMNS
    WHERE OWNER = 'HR'
    ORDER BY TABLE_NAME;
    

The following is the output from the query:

TABLE_NAME           COLUMN_NAME          DATA_TYPE   DATA_LENGTH LAST_ANALYZED
-------------------- -------------------- ---------- ------------ -------------
COUNTRIES            COUNTRY_ID           CHAR                  2 05-FEB-03
COUNTRIES            COUNTRY_NAME         VARCHAR2             40 05-FEB-03
COUNTRIES            REGION_ID            NUMBER               22 05-FEB-03
DEPARTMENTS          DEPARTMENT_ID        NUMBER               22 05-FEB-03
DEPARTMENTS          DEPARTMENT_NAME      VARCHAR2             30 05-FEB-03
DEPARTMENTS          MANAGER_ID           NUMBER               22 05-FEB-03
DEPARTMENTS          LOCATION_ID          NUMBER               22 05-FEB-03
EMPLOYEES            EMPLOYEE_ID          NUMBER               22 05-FEB-03
EMPLOYEES            FIRST_NAME           VARCHAR2             20 05-FEB-03
EMPLOYEES            LAST_NAME            VARCHAR2             25 05-FEB-03
EMPLOYEES            EMAIL                VARCHAR2             25 05-FEB-03
.
.
.
LOCATIONS            COUNTRY_ID           CHAR                  2 05-FEB-03
REGIONS              REGION_ID            NUMBER               22 05-FEB-03
REGIONS              REGION_NAME          VARCHAR2             25 05-FEB-03

51 rows selected.

See Also: