Single Transtact SQL Command

Transtact SQL command is a command non procedural, meaning that the command does not declare the stretcher on the steps executed by the server. Server must analyze command to obtain the most efficient. This process is called optimization and is performed by the query optimizer.

A command, will have several execution plans. Of the possibilities would serve targeted selected a best execution plan, this process is called optimization. Query optimizer is the most important components in a system of the database SQL, because it can handle different conditions without having to change the program.

For example to process a SELECT command, the SQL Server run the following commands:

1. SQL trace and split into logical units such as keywords, expressions, operators, and the identifier.
2. Formed query tree to illustrate the logical steps necessary to change the data source into the desired shape.
3. Query optimizer to analyze all the ways to access the source tables and choose the steps that use the fastest and least resources. Query trees, repaired to record the steps that ultimately yield better execution plans.
4. Database engine started to run the execution plan.

Basic steps for processing the SELECT command can be used for other commands such as INSERT, UPDATE, and the DELETE. UDPATE and DELETE commands that have a target on the set of rows are basically doing the same process with the SELECT command. After the lines obtained were alteration or deletion.