A stored procedure groups one or more Transact-SQL statements into a logical unit, stored as an object in a SQL Server database. After the stored procedure is created, its T-SQL definition is accessible from the sys.sqlmodule catalog view.
When a stored procedure is executed for the first time, SQL Server creates an execution plan and stores it in the plan cache. SQL Server can then reuse the plan on subsequent executions of this stored procedure. Plan reuse allows stored procedures to provide fast and reliable performance compared to noncompiled and unprepared ad hoc query equivalents.
17-1. Selling ...