Microsoft SQL Server 2012 Bible

SQL Server Components

SQL Server is composed of the database engine, services, business intelligence tools, and other items including cloud functionality. This section outlines the major components and tools you need to become familiar with as you begin to explore this platform.

Database Engine

The SQL Server Database Engine, sometimes called the relational engine, is the core of SQL Server. It is the component that handles all the relational database work. SQL is a descriptive language, meaning that SQL describes only the question to the engine; the engine takes over from there.

Within the relational engine are several key processes and components, including the following:

• The Algebrizer checks the syntax and transforms a query to an internal representation used by the following components.
  • SQL Server's Query Optimizer determines how to best process the query based on the costs of different types of query-execution operations. The estimated and actual query-execution plans may be viewed graphically, or in XML, using Management Studio or SQL Profiler.
  • The Query Engine, or Query Processor executes the queries according to the plan generated by the Query Optimizer.
  • The Storage Engine works for the Query Engine and handles the actual reading and writing to and from the disk.
  • The Buffer Manager analyzes the data pages used and prefetches data from the data file(s) into memory, thus reducing the dependency on disk I/O performance.
  • The Checkpoint process writes dirty data pages (modified ...