Transact-SQL Overview

Transact-SQL is central to the use of Microsoft® SQL Server™. All applications that communicate with SQL Server do so by sending Transact-SQL statements to the server, regardless of an application's user interface.

Transact-SQL is generated from many kinds of applications, including:

• General office productivity applications.
  
  
• Applications that use a graphical user interface (GUI) to allow users to select the tables and columns from which they want to see data.
  
  
• Applications that use general language sentences to determine what data a user wants to see.
  
  
• Line of business applications that store their data in SQL Server databases. These can include both applications from other vendors and applications written in-house.
  
  
• Transact-SQL scripts that are run using utilities such as osql.
  
  
• Applications created with development systems such as Microsoft Visual C++®, Microsoft Visual Basic®, or Microsoft Visual J++® that use database application programming interfaces (APIs) such as ADO, OLE DB, and ODBC.
  
  
• Web pages that extract data from SQL Server databases.
  
  
• Distributed database systems from which data from SQL Server is replicated to various databases or distributed queries are executed.
  
  
• Data warehouses in which data is extracted from online transaction processing (OLTP) systems and summarized for decision-support analysis.

For information about how Transact-SQL interacts with APIs and application components such as transaction control, cursors, and locking, see Accessing and Changing Relational Data Overview.