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Oracle SQL Tutorial -10 Data Dictionary

Data Dictionary. Oracle server. Tables containing business data: EMPLOYEES. DEPARTMENTS. LOCATIONS. JOB_HISTORY. ... Data dictionary views: DICTIONARY. USER_OBJECTS. USER_TABLES. USER_TAB_COLUMNS. ... Data Dictionary. User tables are tables created by the user and contain business data, such as EMPLOYEES. There is another collection of tables and views in the Oracle database known as the data dictionary. This collection is created and maintained by the Oracle server and contains information about the database. The data dictionary is structured in tables and views, just like other database data. Not only is the data dictionary central to every Oracle database, but it is an important tool for all users, from end users to application designers and database administrators. You use SQL statements to access the data dictionary. Because the data dictionary is read-only, you can issue only queries against its tables and views. You can query the dictionary views that are based on the dictionary tables to find information such as: Definitions of all schema objects in the database (tables, views, indexes, synonyms, sequences, procedures, functions, packages, triggers, and so on) Default values for columns. Integrity constraint information. Names of Oracle users. Privileges and roles that each user has been granted. Other general database information. Oracle Database 11g: SQL Fundamentals II

Hi ,

In this article I will tell you how to use data dictionary views , what is a data dictionary .

DATA DICTIONARY

HOW TO USE DATA DICTIONARY VIEWS ?

SELECT * FROM DICTIONARY;

DATA DICTIONARY VIEWS

USER_OBJECTS

It gives us information about all objects owned by the user .

  1. Date the object was created ,

  2. Date of last modification ,

  3. Object type ,

  4. The validity of the object .

SELECT * FROM USER_OBJECTS;

ALL_OBJECTS

Gives information about the objects that the user owns and can also access .

SELECT * FROM ALL_OBJECTS;

  1. Tables created by users can be queried ,

SELECT * FROM USER_TABLES;

  1. Columns of tables can be queried ,

SELECT * FROM USER_TAB_COLUMNS;

  1. Constraints created by users can be queried ,

SELECT * FROM USER_CONTRAINTS;

  1. Provides brief information about Constraintler .

SELECT * FROM USER_SEQUENCES;

SELECT * FROM USER_VIEWS;

See you in my next post.

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