How to query the current user in oracle

Oracle database is a commonly used relational database management system. In the Oracle database, each user has a unique username and password, and can log in to the database and perform operations through the username and password. When querying the current user, you can use Oracle's built-in functions and system variables to obtain the current user's information.

Method 1: Use the USER function to query the current user

In the Oracle database, you can use the built-in function USER to query the user name of the current user. The USER function returns the user name of the current database session, that is, the current user executing the query.

Example:

SELECT USER FROM DUAL;

Execute the above SELECT statement to query the user name of the current user.

Method 2: Use the SYS_CONTEXT function to query the current user

In addition to using the USER function, you can also use the SYS_CONTEXT function to query the current user's information. SYS_CONTEXT is a built-in function that returns context information for the current session. By setting different parameter values, the SYS_CONTEXT function can return different context information, including user name, session ID, IP address, etc.

Example:

SELECT SYS_CONTEXT('USERENV', 'SESSION_USER') FROM DUAL;

Executing the above SELECT statement will return the user name of the current session.

Method 3: Use system variables to query the current user

Oracle database also provides some system variables that can be quoted in SQL statements to obtain the current user's information. Among them, the SESSION_USER and USERID variables can be used to query the user name and user ID of the current user.

Example:

SELECT SESSION_USER, USERID FROM DUAL;

Executing the above SELECT statement will return the user name and user ID of the current session.

Summary:

Querying the current user in the Oracle database is very simple. You can obtain the current user's information through built-in functions, system variables, etc. In practical applications, querying the current user's information can be used for recording, statistics, permission control, etc.

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