SQL Server Express
Microsoft SQL Server Express, a freely downloadable and distributable version of Microsoft's SQL Server relational database management system, comprises a database specifically targeted for embedded and smaller-scale applications.
Unlike its predecessor, MSDE, it lacks a concurrent workload-governor to "limit performance if the database engine receives more work than is typical of a small number of users." It has a number of technical restrictions (which make it unsuitable for some large-scale deployments) including:
- Maximum database size of 10 GB per database in SQL Server 2008 R2 (4 GB for SQL Server Express 2008 and earlier; compared to 2 GB in the former MSDE). The limit applies per database (log files excluded); but in some scenarios users can access more data through the use of multiple interconnected databases.
- No SQL Server Agent service
- Hardware-utilization limits:
- Single physical CPU, but multiple cores allowable
- 1 GB of RAM (runs on a system with any RAM amount, but uses only at most 1 GB)
- SQL Server Management Studio Express
- SQL Server Configuration Manager
- SQL Server Surface Area Configuration tool
- SQL Server Business Intelligence Development Studio.
Features available in SQL Server "Standard" and better editions but absent from SQL Server Express include:
Microsoft makes SQL Server Express available as:
- An integrated edition with management tools
- Core database-engine only
- A SQL Server Express with Advanced Services edition (first introduced relatively late in Q2 2006 compared to the original release) with a reduced-functionality version of SQL Server Reporting Services and with full-text search capabilities
In the Free 2005 Express version, for example, a standard approach to installation options was provided (as follows). Generally the SQL 2005 Express installers are packaged with the following consistent naming convention:
- Has installers for BOTH 32-bit & 64-bit processors, but is a basic install
- Has ONLY the installer for 32-bit processors (still the basic install)
- Has installers for BOTH 32-bit & 64-bit processors AND SQL Server Management Studio Express (SSMSE) (2008 R2)
- Has the basics AND SQL Server Management Studio Express (SSMSE) + Reporting & Full Text Queries
- Has the basics and SSMSE and Business Intelligence Development Studio (BIDS)
These optional variants have gone through several service packs, and each SP installer can be used without using the older ones first:
|This article is outdated. (April 2012)|
- Originals of the above files all carry the version number 9.0.1399.6
- Service Pack 2 (SP2) versions all carry the version number 9.0.3042
- Service Pack 3 (SP3) versions all carry the version number 9.00.4035
- Service Pack 4 (SP4) versions all carry the version number 9.00.5000
Whilst the naming and versioning has been very consistent and simple, many reports exist on the web of major installation problems, which in some cases can be traced back to using installers of different names and versions to attempt to install only parts of what they provide. This results in apparent partial installation failures. In general the best approach is to uninstall an older service pack completely and then reinstall all that is needed from the appropriately named file of the latest SP.
Version history 
|Version||Release date||Mainstream Support End Date||Extended Support End Date|
|SQL Server 2005 Express Edition||2005-11-07||2011-04-12||2016-04-12|
|SQL Server 2008 Express||2009-02-08||2014-07-08||2019-07-09|
|SQL Server 2008 R2 Express||2010-04-16||2014-07-08||2019-07-09|
|SQL Server 2012 Express||2012-05-14||2017-07-11||2022-07-12|
See also 
- SQL Server Compact
- Microsoft Servers
- List of relational database management systems
- Comparison of relational database management systems
- "The SQL Server 2000 Workload Governor". MSDN. January 2004. Retrieved 2007-01-15.
- "Features Supported by the Editions of SQL Server 2008 R2". Retrieved 2010-06-22.
- "Compare Edition Features".
- "SQL Server Express with Advanced Services Features". Microsoft. Retrieved 28 March 2012.
- "How SQL Server 2005 Express Edition determines the CPU count and uses the CPUs during processing". MSDN. November 2008. Retrieved 2008-11-25.
- "How do I Manage SQL Server".
- "Download Microsoft SQL Server 2005 Express Edition from Official Microsoft Download Center". Retrieved 26 December 2012.
- "Microsoft Support Lifecycle (SQL Server 2005)". Retrieved 26 December 2012.
- "Download Microsoft SQL Server 2008 Express from Official Microsoft Download Center". Retrieved 26 December 2012.
- "Microsoft Support Lifecycle (SQL Server 2008)". Retrieved 26 December 2012.
- "Download Microsoft SQL Server 2008 R2 - Express from Official Microsoft Download Center". Retrieved 26 December 2012.
- "Microsoft Support Lifecycle (SQL Server 2008 R2)". Retrieved 26 December 2012.
- "Download Microsoft® SQL Server® 2012 Express from Official Microsoft Download Center". Retrieved 26 December 2012.
- "Microsoft Support Lifecycle (SQL Server 2012)". Retrieved 26 December 2012.
- Microsoft SQL Server Previous Editions
- Microsoft SQL Server 2012 Express Edition - Overview and Download
- SQL Server 2012 Comparison of features by edition
- SQL Server Express WebLog