Oracle Data dictionary document classic edition details

The following articles mainly describe Oracle Data Dictionary documents, it is worth noting that the correct application of Oracle data dictionary and actual operations and specific operations in actual operations are the main content of this article.

 
 

  
  
select * from dictionary; 
 
 

Oracle Data Dictionary

A data dictionary is a place where Oracle stores database information. It is used to describe data.

For example, the Creator information, creation time information, tablespace information, and user access permission information of a table.

The Oracle Data dictionary is a set of tables and view structures. They are stored in the SYSTEM tablespace.

You can access the data dictionary to view detailed information when you encounter difficulties in performing operations on the data in the database.

You can use SQL statements to access the database data dictionary.

The Oracle Data dictionary includes:

1. Information about all schema objects in the database, such as tables, views, clusters, and indexes.

2. How much space is allocated and how much space is currently used.

3. Column default value.

4. Constraints on information integrity.

5. Oracle user name.

6. permissions granted to users and roles.

7. Audit information accessed or used by the user.

8. Other generated database information.

Data dictionaries in Oracle are static and dynamic.

1. Static Data Dictionary> it does not change when users access the data dictionary,

For example, a table created by a user

2. Dynamic Data Dictionary> depends on the performance of database operations and reflects some internal information about database operations. Therefore, it is not always the same when accessing such data dictionary.

Currently locked object

Static Data Dictionary: This type of Oracle Data Dictionary is mainly composed of tables and views.

The tables in the data dictionary cannot be directly accessed, but the views in the data dictionary can be accessed.

The views in the static Oracle Data Dictionary are divided into three types, which have three prefixes: user _ *, all _ *, and dba _*.

User _*

This view stores information about the objects owned by the current user. All objects in this user mode)

All _*

This attempt stores the information of objects accessible to the current user. Compared with user _ *, all _ * does not need to own this object. You only need to have the permission to access this object)

Dba _*

This view stores information about all objects in the database. The premise is that the current user has the permission to access these databases. Generally, the user must have the Administrator permission)

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Select * from dictionary;

Queries the tables owned by the user.

User_tables mainly describes information about all tables owned by the current user,

It mainly includes the table name, table space name, and cluster name. Through this view, you can clearly understand what tables can be operated by the current user

 
 

  
  
desc user_tables;  
  
  
select table_name from user_tables;  
  
  
select * from user_tables;  
 
 

Queries the indexes owned by the user.

 
 

  
  
select index_name from user_indexes; 
 
 

Query the views of a user.

 
 

  
  
select view_name from user_views; 
 
 

Queries the database objects owned by the user, including tables, views, stored procedures, triggers, packages, indexes, sequences, and JAVA files.

 
 

  
  
select object_name from user_objects; 
 
 

It mainly describes the information of the current user, including the current user name, account id, account status, tablespace name, and creation time.

 
 

  
  
select * from user_users;  
  
  
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User _/all _ differences:

The information listed in all _ is the objects that the current user can access, rather than the objects owned by the current user.

Queries all tables, processes, and functions of a user. The above content is part of the content description of the Oracle Data dictionary document. I hope it will help you in this regard.