Microsoft released LocalDB a couple of weeks ago as part of SQL Denali CTP 3. LocalDB or Local Database Runtime is the new version of SQL Express created specifically for developers. It carries the same features as SQL Express, but in addition, installs faster, has fewer prerequisites, and doesn’t require management of a database instance.
Here are some important points to note about LocalDB:
- LocalDB does not replace SQL Express, it is an addition to the express family, meant specifically for developers
- It runs as a separate process, rather than as a service.
- same memory limitations as Express.
- uses the same sqlservr.exe as the regular SQL Express and other editions of SQL Server
- you can create and start a user instance without installing the parent SQL Express instance
- applications will use the same client-side providers (ADO.NET, ODBC etc) to connect to it
- multiple LocalDB processes can exists on same machine
- no database services in LocalDB
- LocalDB runs in the same security context as the calling application
- you can attach to database using file location – support for AttachDbFileName property
- Currently, you must install SQL Server Express Edition in Denali CTP 3 and select LocalDB as a feature. In future, LocalDB may be available as a separate, smaller installer.
- Currently no support for .NET 4, but planned in future