AJAX Database Connectivity is the Data Access Component of OAT (OpenLink AJAX Toolkit). It's basically an XML for Analysis (XMLA) client that enables the development and deployment of database independent Rich Internet Applications (RIAs). Thus, you can now develop database centric AJAX applications without lock-in at the Operating System, Database Connectivity mechanism (ODBC, JDBC, OLEDB, ADO.NET), or back-end Database levels.

XMLA has been around for a long time. Its fundamental goal was to provide Web Applications with Tabular and Multi-dimensional data access before it fell off the radar (a story too long to tell in this post).

AJAX Database connectivity only requires your target DBMS to be XMLA (direct), ODBC, JDBC, OLEDB, or ADO.NET accessible.

I have attached a Query By Example (QBE) screencast movie enclosure to this post (should you be reading this post Web 1.0 style). The demo shows how Paradox-, Quattro Pro-, Access-, and MS Query-like user friendly querying is achieved using AJAX Database  Connect Connectivity