module 03_creating and managing databases

8/9/2019 Module 03_Creating and Managing Databases

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Module 3:Creating and Managing

Databases

Vidya Vrat Agarwal. | MCT, MCSD


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SQL Server Database

A Database is a collection of Tables and Objects such as Views,Triggers, Stored Procedures.

The Data and Objects in a database are stored as a set of Operating

System files.

The types of files that are used to store a database in SQL Server are:

Primary

Secondary

Transaction Log

A database must consist of a Primary data file and one Transaction

log file.

The Primary data file can be used for database objects, and

Secondary data files can be used to store User data and objects.

Contd..


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SQL Server Database

Database need not have Secondary data file, if the PrimaryData file is Large Enough to hold the data in Database .

The Transaction log records all the modification that haveoccurred in the database and which transaction performed

the modifications. E.g-Insert, Update, Delete.The Transaction log files hold the log information used torecover a database. There can be more than onetransaction log file.

The Primary data file has a .mdfextensionThe Secondary data file has a .ndfextension

The Transaction log file has a .ldfextension


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Creating Database

CREATE DATABASE Sample

ONPRIMARY ( NAME = SampleData,FILENAME ='c:\Program Files\Data\Sample.mdf',SIZE = 10MB,MAXSIZE = 15MB,FILEGROWTH = 20% )

LOG ON

( NAME = SampleLog,FILENAME =c:\Program Files\Data\Sample.ldf',SIZE = 3MB,MAXSIZE = 5MB,FILEGROWTH = 1MB )

CREATE DATABASE Sample

ONPRIMARY ( NAME = SampleData,FILENAME ='c:\Program Files\Data\Sample.mdf',SIZE = 10MB,MAXSIZE = 15MB,FILEGROWTH = 20% )

LOG ON( NAME = SampleLog,FILENAME =c:\Program Files\Data\Sample.ldf',SIZE = 3MB,MAXSIZE = 5MB,FILEGROWTH = 1MB )

Creating a Database Defines:The name of the databaseThe size of the databaseThe files where the database will reside


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SizeThis parameter specifies the size of the data or log file. Youcan specify sizes in megabytes (MB)the default valueorkilobytes (KB). The minimum size is 512 KB for both thedata and log file.

MaxSize

This parameter specifies the maximum size to which the filecan grow. You can specify sizes in megabytesthe default

valueor kilobytes.

If you do not specify a size, the file grows until the disk isfull.


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FileGrowthThis parameter specifies the growth increment of the file.

The FILEGROWTH setting for a file cannot exceed theMAXSIZE setting. A value of 0 indicates no growth.

The value can be specified in megabytesthe defaultinkilobytes, or as a percentage (%).

The default value if FILEGROWTH is not specified is 10percent, and the minimum value is 64 KB (one extent).

The specified size is rounded to the nearest 64 KB. in three

ways: in megabytes, in kilobytes, or as a percentage. Thepercentage only applies to file growth, not maximum size.


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Retrieving Database Information

Determine Database Properties by Using theDATABASEPROPERTYEX Function

Use System Stored Procedures to Display InformationAbout Databases and Database Parameters

sp_helpdb

sp_helpdb database_name

sp_spaceused [objname]


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FileGroups

A FileGroup is a Collection of files. The Files may or may notbe on the same Disk Drive.

Purpose

FileGroups improve the performance of the database .

For Better database performance, files and filegroups shouldbe created on different disks.


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Filegroups

Northwind Database

Default Filegroup OrderHistoryGroup

sys...sys...sys...

sys...sys...sys...

sysuserssysuserssysusers

sysobjectssysobjectssysobjects

.........

OrdersOrdersOrders

CustomersCustomersCustomers

ProductsProductsProducts

OrdHistYear2OrdHistYear2OrdHistYear2

OrdHistYear1OrdHistYear1OrdHistYear1

Northwind.mdfNorthwind.mdf

C:\ D:\

OrdHist1.ndfOrdHist1.ndf

OrdHist2.ndfOrdHist2.ndf Northwind.IdfNorthwind.Idf

E:\


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Managing Data and Log File Growth

ALTER DATABASE Sample

MODIFY FILE ( NAME = 'SampleLog',SIZE = 15MB)

GO


ADD FILE

( NAME = SampleData2,FILENAME ='c:\Program Files\..\..\

Data\Sample2.ndf',

SIZE = 15MB,MAXSIZE = 20MB )

GO


MODIFY FILE ( NAME = 'SampleLog',SIZE = 15MB)GO


ADD FILE

( NAME = SampleData2,FILENAME ='c:\Program Files\..\..\

Data\Sample2.ndf',

SIZE = 15MB,MAXSIZE = 20MB )

GO

Using Automatic File Growth Expanding Database Files

Adding Secondary Database Files


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Renaming a Database

The database should not be in use when it is being renamed .

sp_renamedb old_Dbname, new_Dbname

Example sp_renamedb employee,emp


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Dropping a Database

DROP DATABASE Northwind, pubsDROP DATABASE Northwind, pubs

Methods of Dropping a Database

SQL Server Enterprise Manager

DROP DATABASE statement

Restrictions on Dropping a Database

When a user is connected to it If it is a system database


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DatabaseDatabase

How Data Is Stored

Extent

(8 contiguous8-KB pages)

Page (8 KB)

Tables,

Indexes

Data

1 2 3 5 6 7 8

4

Data (file)

.mdf or .ndf

Log (file)

.Idf


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SQL Server stores, reads, and writes data in 8-KBblocks of contiguous disk space called Pages.

All pages are stored in extents. An extent is eightcontiguous pages, or 64 KB.

This means that a database can store 128 pages permegabyte.

1 MB = 1024 KiloBytes

1024 KB / 8 KB (Page) = 128 Pages per MB

1024 KB / 64 Kb (Extent) = 16 Extents per MB


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Pages

Pages and extents are the primary data structures in theSQL Server physical database.

Types of Pages

SQL Server uses several types of pages:

some track space allocation, and

some contain user and index data.


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Extents

Types of Extents

SQL Server uses two types of extents:

Mixed Extents

Extents that contain pages from two or more objects arecalled Mixed Extents.

Every table starts as a mixed extent. Database

use mixed extents primarily for pages that

track space and contain small objects.

MixedExtent


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Extents

Uniform Extents

Extents that have all eight pages allocated to a single objectare called uniform extents. They are used when tables orindexes need more than 64 KB of space.

UniformExtents


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Check Your Understanding.


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Q.1. What are the types of files to storea Database in SQL Server. ?


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Q.2. The Primary data file has a _______ extension. ?


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Q.3. The Secondary data file has a __________ extension.


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Q.4. The Transaction log file has a ________ extension.


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Q.5. What is the Command to create a Database inSQL Server. ?


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Q.7. What is the difference between Name andFilename. ?


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Q.8. What is the difference between Size andMaxsize. ?


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Q.9. What is the SQL Statement to delete adatabase. ?


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Q.10. What is FileGroup and what is its Purpose. ?


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Q.11. What is the Command to renamea database?


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Q.12. What is the difference between Mixed andUniform extents .


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Winners dont dodifferent thingsthey do thingsdifferently.Thank You.

module 03_creating and managing databases

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