The primary purpose of a Microsoft® SQL Server™ database is to store data and then make that data available to authorized applications and users. While database administrators create and maintain the database, users work with the contents of the database using DML statements. DML statements are used to work with data in an existing database. The most common DML statements
SELECT
INSERT
UPDATE
DELETE
Commands sent to SQL Server are Transact-SQL statements.
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. These four statements form the core of the SQL language. Understanding how these four statements work is a large part of understanding how SQL works. The SELECT statement is used to retrieve existing data. The UPDATE statement is used to change existing data. The INSERT statement is used to add new data rows. The DELETE statement is used to remove rows that are no longer needed.
Keep in Mind:
Accessing, or retrieving, existing data The SELECT statement is used to retrieve existing data.
Adding, or inserting, new data The INSERT statement is used to add new data rows.
Changing, or updating, existing data The UPDATE statement is used to change existing data.
Deleting existing data The DELETE statement is used to remove rows that are no longer needed.
Note
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