SQL Server

SQL Server is relational database management server whose basic purpose is to store and retrieve data as per user's request. The retrieval of data is based on structured query language (SQL). The query can be from a user on the same computer or a user across a network. There are different versions of SQL Server; the latest is SQL Server 2012 was released on March 6, 2012. The other popular ones are SQL Server 2008 R2, SQL Server 2008, SQL Server 2005 and SQL Server 2000.

SQL was written in powerful C++ programming language and now is available in many languages including English, Chinese, French, German, Italian, Japanese, Korean, Portuguese (Brazil), Russian and Spanish.

SQL Server Editions:

The different editions of SQL Server are available for different stream of users. These are

Main Stream

  • Datacenter – Datacenter is a full fledged edition of SQL Server and supports many processors
  • Enterprise – has many tools for creating or managing clusters also includes core database engine and add-on services
  • Web – used as a option for Web hosting in low total cost of ownership
  • Other Main Stream editions are Business Intelligence, Workgroup, Express and Standard

Specialized Stream

  • Azure – Azure Database the cloud based version of SQL Server
  • Compact (SQL CE) – Compact Edition is based on SQL mobile. It is small in size and has fewer features than other editions
  • Developer – Developer edition's features are similar to SQL Server 2012 Enterprise Edition but cannot be used as production server. It can be downloaded and used free of charge and used as development and test system.
  • Embedded (SSEE) – Embedded Edition is an especially configured instance of Express database engine
  • Evaluation – is a 180 days trial edition and has all the features of Enterprise Edition.
  • Fast Track and Parallel Data Warehouse (PDW)

Architecture

Data Storage

Data is stored in database in columns. Different data types are available like Integer, float, decimal, char, etc., which can store data depending upon user’s needs. Physically table is rows are stored in number of partitions. Rows are stored in each partition is in B-tree or heap structure.

To retrieve data from SQL server data, queries are used. A query can be written in many different ways. Using a single query multiple tables can be accessed. SQL buffers upto 8 KB pages in RAM.

Transaction

Every database transaction executed on SQL Server must be consistent and reliable. For this SQL Server transactions satisfies ACID properties, i.e. (A-atomicity, C-consistency, I-isolation, D-durability). The ACID compliant of SQL Server makes sure when multiple clients access or modify data at a time, data integrity is maintained. The use of shared and exclusive locks ensures concurrent access thereby preventing deadlocks.

Useful Info:

Undelete files from Windows Server 2003
SQL database files are stored as .mdf, ndf on Windows Server 2003. These files stored on your Windows server 2003 might be deleted due to many reasons unknown to user. Some possible reasons for deletion are third party utility malfunction, file system corruption or power surge. If you have lost / deleted important database files, use Remo Recover (Windows) and retrieve the files quickly.

Safe and Secure
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