sql server architecture

SQL Database Architecture

SQL database is divided into logical and physical components.

Logical Component

Logical components comprises of following: 

Database objects, Collation, Login, Users, Roles and groups.

Physical component

Physically components exist as two or more files on disk.

Physically files can be of three types.

1.Primary data files

This is starting point of the database and contain pointer to point other files. Extension is mainly .mdf .

2.Secondary data files

It consists of data other than primary data file. Extension is mainly .ndf .

3.Log files

It contains log information which is used to recover database.

Flow of architecture:-

we have two files data files ,log files.

In log files we have

    

               1. In active portion

               

               2. Active Portion

Every transaction enter through log file of active portion of log . once it is get committed it will raise the check point or it 

will moves to the data files and maintain the copy of the data inactive portion of log file.

Check Point :-

Its process of flesh out the data from active portion of  log to .mdf and copy the duplication of data in inactive 

portion of  .ldf or logfile.