IBM developed SQL in late 1970s. The term stands for Structured Query Language, and is pronounced "sequel”. Of the several types of databases in the market, Microsoft SQL Server is certainly the most popular (after MySQL of course).
Version 1.0 of Microsoft's SQL Server was first released in 1989. Today, it boasts of nine different versions, the latest being 10.5, popularly known as Microsoft SQL Server 2008 R2. It's a relational database, and its primary query languages are T-SQL and ANSI-SQL.
Microsoft SQL is currently available in nine different editions. These are SQL Server Compact Edition, Datacenter Edition, Developer Edition, Enterprise Edition, Evaluation Edition, Express Edition, Standard Edition, Web Edition and Workgroup Edition
SQL Server Express Edition is a free and easy-to-use version of SQL Server that is lightweight and embeddable. Database management becomes an easy job with SQL server, thanks to powerful features such as SQL Server Management Studio Express. Now that we've talked about the basic features of SQL Server Express Edition, let me explain some of its limitations.
CPU support: The biggest drawback of SQL Server Express lies in the fact that it can use only one CPU at a time. Even if installed on a server with more than one CPU, it will use only one of them at a time.
Memory usage: For data buffering, SQL Server Express uses a maximum 1GB memory. Even if your server has more than 1 GB, the remainder will not be used.
Database size: With SQL Server Express, the maximum permitted database size is 4GB.
Absence of profiler: Unfortunately, the SQL Server Express does not include this powerful tool.
Absence of job scheduler: SQL Server Express does not provide a job scheduling service.
No import/export: You cannot import or export data while using the SQL Server Express.
File groups per database: This server allows a maximum of 32,767 file groups per database.
No server agent service: The ‘SQL Server Agent’ service is absent in SQL Server Express.
No analysis services: This server edition does not provide the Microsoft analysis services related to business intelligence and data warehousing.
No integration services: Again, this edition does not provide integration services used for data migration.
GUI tools available with this server simplify database management, but overall the free edition of Microsoft SQL still needs addition of a number of capabilities to make it more robust and developer-friendly.