connected model Vs. disconnected model

hi !!
i have a question about the connected and disconnected model to access the Sql server DB......i know that there is better to choose one rather than the other in some situantions and there is no better model in all cases..... os i hope you can help me to decide what shall i choose...
i will use the DB to connect to Web services and read data from the DB and wrtie some data back......i do not know that to use .... i hope you advise me and tell me about the rules that will allow me to choose what model to choose ... i appreciate your help!!
Thanks !!!Very basically, if you're a single user application then you may get a benefit from staying connected. If you're expecting many users then disconnected is the way forward. Given the very disconnected nature of a web service I would think the clue is in the question...although re-reading your question I'm not sure who is the client and who is the server.|||my project will be a WS that will send SMS .... user will have a directory daved in the DB and contains addresees and groups that users can send them SMS and after the SMS goet sent i will dave all the information in the database...i think mainly i will use the insert and select commands and the update and the delete will be less used in the system.
i hope that will give you a good overview about the project.
thanks for your reply and i appreciate your help!