But ODBC has the advantage of being generic, so the application won't notice if the back- end changes. Another database capability to look for is a tool's support for the Structured Query Language. SQL is the lingua franca of database programming. In Web applications you want to be able to embed SQL statements, passing through to the database for processing, by either coding directly or using a wizard. The other way to run SQL is to call stored procedures, which are precompiled SQL functions stored on and executed by the database.
Databases are only one tier of a multitier application.
Once you have that data, however, you want to process it. There is a middle tier that acts on the data according to business rules. This tier runs on a machine separate from the database server, the application server. The next tier in the application is the client tier. In the Web applications being discussed here, the client is always a browser.