Traditionally web application development has required web developer(s) and database developer(s).
Those web developers are dying or already dead now.
They're being replaced by a new breed of "web application developers" who can do much more than their predecessors. This new specie can develop a web application from A to Z... from top to bottom. They possess not only the typical web development skills but also enough database skills to crank out a web application of simple to medium complexity all by themselves.
This trend is here to stay... When I look back, till about 2 - 3 years ago all development teams needed a database developer; now some teams build an application without a database specialist.
There are many reasons for this shift including maturity in technologists (polyskilled) and technology (abstraction of database in frameworks like Ruby on Rails) etc.