Database connection: Difference between revisions

Revision as of 10:12, 7 August 2019

Revision as of 10:32, 7 November 2019

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Database connections are finite and [[time complexity|expensive]] and can take a disproportionately long time to create relative to the operations performed on them. It is very inefficient for an application to create, use, and close a database connection whenever it needs to update a database.

[[Connection pool]]ing is a technique designed to alleviate this problem. A pool of database connections can be created and then shared among the applications that need to access the database. When an application needs database access, it requests a connection from the pool. When it is finished, it returns the connection to the pool, where it becomes available for use by other applications.

The connection object obtained from the connection pool is often a wrapper around the actual database connection. The wrapper understands its relationship with the pool, and hides the details of the pool from the application. For example, the wrapper object can implement a "close" method that can be called just like the "close" method on the database connection. Unlike the method on the database connection, the method on the wrapper may not actually close the database connection, but instead return it to the pool. The application need not be aware of the connection pooling when it calls the methods on the wrapper object.