Most scientific data is not in databases. There are many non-standard databases in biology. They are widely distributed. The structure can be relatively complex.
Volatility is a problem.
New databases are created and existing structures get changed. Because programmers don't understand the science, they don't understand the databases. Return all genomic sequences for which alu elements are located internal to a gene domain. The Next Challenge We need to make it possible for scientists to understand and manipulate their own data. Data models are important.