Call Prepare to have the remote database server allocate resources for the query and to perform additional optimizations. Calling Prepare before executing a query improves application performance. 

A query is automatically prepared before being executed. A query that was automatically prepared will then be automatically unprepared after it executes. When a query will be executed a number of times, an application should always explicitly prepare the query to avoid multiple and unnecessary prepares and unprepares. 

Preparing a query consumes some database resources, so it is good practice for an application to unprepare a query once it is done using it. The UnPrepare method unprepares a query.