SPS 3.0 and MOSS 2007 Single Server Installs
A single server install of MOSS 2007 will install SQL Server 2005 Express Edition and therefore each content database will be limited to 4GB. Therefore, a site collection (if given its own content database) will be limited to 4GB of content.
A SPS 3.0 single server install does not install SQL Server 2005 Express Edition – instead it installs the Windows Integrated Database (WID), which is also known as SQL Server 2005 Embedded Edition. The instance name is “MICROSOFT##SSEE”, and there are several limitations such as external connections are not permitted.
However, most importantly, WID databases do not have the 4GB limitation, and so practically speaking, the content size for a site collection is unlimited.
The database files are installed into “\WINDOWS\SYSMSI\SSEE\MSSQL.2005\MSSQL\Data” which is typically located on drive C. This can cause problems as many servers use another drive for storing data.
The easiest way of moving a content database from the default location to another location is to perform a backup of the web application using Central Administration and then restore to the new location.