Thursday, November 06, 2014

TSQL Tutorial : Creating a Database

Creating a Database
You might already have a database in which you can create some temporary tables for the purpose of
working through the examples. If you don't, creating one is easy enough. In Transact-SQL, you
create databases using the CREATE DATABASE command. The complete syntax can be quite complex, but
here's the simplest form:
Run this command in Query Analyzer to create a scratch database for working through the examples in
This book. Behind the scenes, SQL Server creates two operating system files to house the new database:
SQLSERVERQUEST.MDF and SQLSERVERQUEST.LDF. Data resides in the first file; transaction log
Information lives in the second. A database's transaction log is the area where the server first carries out
changes made to the data. Once those changes succeed, they're applied atomically—in one piece—to the
actual data. It's advantageous for both recoverability and performance to separate user data from
transaction log data, so SQL Server defaults to working this way. If you don't specifically indicate
transaction log location (as in the
Example above), SQL Server selects one for you (the default location is the data directory that was
Selected During installation).
Notice that we didn't specify a size for the database or for either of the les. Our new database is set up so
That it automatically expands as data is inserted into it. Again, this is SQL Server's default mode of
This one feature alone—database files that automatically expand as needed—greatly reduces the database
administrator's (DBA's) workload by alleviating the need to monitor databases constantly to ensure that
they don't run out of space. A full transaction log prevents additional changes to the database, and a full

data segment prevents additional data from being inserted.

TSQL Tutorials..........

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