How to disconnect database usage of SQL

You can use SQL statements to disconnect database connections, including: 1. CLOSE statement: close the specified connection immediately; 2. DISCONNECT statement: close the connection and release the resources; 3. END TRANSACTION statement: submit/roll back the transaction and disconnect; 4. EXIT statement: terminate the script and close all connections; 5. Connection object method (specific to the database system). Additionally, it is recommended to commit or roll back unfinished transactions before disconnecting.

SQL Disconnecting the database

Disconnecting the database is a necessary operation, especially if it is no longer needed or system resources are to be released. Here is how to use SQL to disconnect from a database:

1. Use CLOSE statements

The easiest way is to use the CLOSE statement. It will immediately close the specified database connection:

 <code class="sql">CLOSE connection_name;</code>

2. Use the DISCONNECT statement

The DISCONNECT statement is similar to the CLOSE statement, but in addition to closing the connection, it also releases all server resources associated with the connection:

 <code class="sql">DISCONNECT;</code>

3. Use the END TRANSACTION statement

If the database is in a transaction, the END TRANSACTION statement commits or rolls back the transaction and disconnects from the database:

 <code class="sql">END TRANSACTION;</code>

4. Use EXIT statements

The EXIT statement immediately terminates the current script or batch file and closes all open connections:

 <code class="sql">EXIT;</code>

5. Use the Connection Object Method (only applicable to some database systems)

Some database systems (such as psycopg2 in Python) provide connection object methods to disconnect:

 <code class="python">import psycopg2 connection = psycopg2.connect(...) # 断开连接connection.close()</code>

Notice:

• In all cases, it is best to commit or roll back any unfinished transactions before disconnecting.
• The specific syntax and available options may vary depending on the database system you are using. Please refer to the database documentation for accurate information.

The above is the detailed content of How to disconnect database usage of SQL. For more information, please follow other related articles on the PHP Chinese website!