Is it possible to connect any database from flex directly?
Not unless you use Adobe AIR for desktop at which time you'd be using the SQLLite api's to create/connect to a sqlite database file.
http://livedocs.adobe.com/flex/3/html/help.html?content=SQL_01.html
Anything else is going to require a back end service to handle such transactions.
You can use asSQL as mentioned by michael, or use the Adobe Air runtime.
However, this must be said about using this library: It is EXTREMELY insecure to have a straight database connection from the client unless it's from Adobe Air since the db is local.
You don't want to send your username/password over the internet to connect to a database unless you really don't care about the data or security of your data. I would recommend you use a middleware solution, like PHP or Java that interfaces your database for your client to get the data it needs.
来源：https://stackoverflow.com/questions/5418055/connecting-any-database-directly-from-flex