You'll definitely want to use one. Organizing and storing data is what computers do best. Building your web application around a database is a natural way to build flexibility.
- We like Microsoft SQL Server because it offers great performance and all the important features required for OLTP and OLAP at a very reasonable price.
- MySQL is an open source alternative, now owned by Oracle, that is gaining in popularity on the Linux, Apache stack.
- Oracle and DB2 are comparable, arguably superior, to MS SQL in capability, but are much more expensive for small to medium size applications.
- File databases like MS Access are easy and inexpensive, but are severely limited for anything but the smallest use. Having a big company providing upgrades and support for this strategic product is definitely a plus.
Critically important features include standard SQL, full text search, remote administration, stored procedures, error handling, solid security, programming interface, robust multiuser transaction processing and analytics.