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What is Database Architecture ?

2020-04-17T18:50:00.000-07:00

Each database will be divided into two types of implementations
•Logical implementation
Tables, views, procedures ..etc
•Physical implementation
.LDF, .MDF and NDF files

When using a database, you work primarily with the logical components such as tables, views, procedures ..etc The physical implementation of files is largely transparent. Typically, only the database administrator needs to work with the physical implementation.

What is Physical Data Base ?

2020-04-17T17:50:00.000-07:00

Physical Db will be divided in to 3 types:
1) .MDF 2) .LDF 3) .NDF

MDF is a file extension associated with Microsoft SQL Server primary data file.
LDF is a file extension associated with SQL Server Secondary Transaction log file.
NDF is a file extension associated with SQL Server Secondary Data file.
.MDF & .NDF having DB related data
.LDF having logs related data

On Physical Database contains File Groups and Transaction log
In File Group Contains Data Files
Data File contains Tables
Tables contains Extents
Extents contains Pages
pages Contains Rows

Transaction log is User defined file group by default it's

Logical - database objects like view,Sp,functions,Triggers,Indexes and roles etc..

What is DEP(Data Execution Prevention) ? How to configure DEP settings?

2020-04-17T01:49:00.000-07:00

What is Data Execution Prevention

Data Execution Prevention (DEP) helps prevent damage from viruses and other security threats
that attack by running (executing) malicious code from memory locations that only Windows and
other programs should use. This type of threat causes damage by taking over one or more memory
locations in use by a program. Then it spreads and harms other programs, files, and even your e-mail contacts.

To configure DEP settings for Windows Server 2003 & ....

Need to modify Boot.ini file to prevent from this type of issues.

Physical Path of Boot.ini
1. Go to C: Drive
2. Click on Tools >> Folder Options >> view >> Uncheck "Hide protected operationg system files (Recommended)" >> Click OK
3. Now you can see the Boot.ini file

Change from /noexecute=####### to /noexecute=AlwaysOn and restart the computer.

To configure DEP settings for Windows and later & ....

1. Click Start, click Control Panel, and then double-click System.

2. Click the Advanced tab. Then, under Performance, click Settings.

3. Click the Data Execution Prevention tab.

4. Click Turn on DEP for essential Windows programs and services only to select the OptIn policy.

5. Click Turn on DEP for all programs and services except those I select to select the OptOut policy.

6. If you selected the OptOut policy, click Add and add the applications that you do not want to use DEP with.

Ref:
http://support.microsoft.com/kb/875352#5
http://channel9.msdn.com/forums/TechOff/227400-What-is-Data-Execution-Prevention-and-why-does-it-shut-down-IIS/
http://technet.microsoft.com/en-us/library/cc738483%28WS.10%29.aspx

Actual error is
Unexpectedly my website giving "Service Unavailable" message

"To help protect your computer, Windows has closed this program.
Name: IIS Worker Process
Publisher: Microsoft Corporation
[Change Settings] [Close Message]"

To avoid this error please read above information

Note: Please configure DEP settings at your server.