Small businesses that are adopting small applications with databases have a number of non-expensive choices. This blog will try to compare two Microsoft products - Access 2003 and SQLExpress 2005 as a database for small application with database size smaller than 4 GB.
 

	Access 2003	SQLExpress 2005
Product	Microsoft Office Product	Microsoft Free Database Product
Size Limitation	2 GB	4 GB
Allowed concurrent users	5	no limit
Database connection provider	ODBC or OLEDB provider	SQL, ODBC or OLEDB provider
Built-in backup support	no	support backup and recovery internally
Login security	simple username/password login control	enterprise level login security architecture
Upgradeable to enterprise database	no	yes (can be upgraded to SQL Server 2005 without rewriting any database objects)

The conclusion is:if your application is very small with less than 5 concurrent users, Access is perhaps your choice else SQLExpress 2005 is the route to go.