Which one is the best ?

In any type of application (web/ desktop) which one is the best ?

1. making and closing the connection with database for each and every use.
or
2. make a connection and use that connection until the end of application.
or
3. whether, it depends upon the data source and/or application.?

please explain,

Thank you.

Is this an interview question?

no no,
not like that,
just i want to know, how making and closing a connection will effects the total performance, that's it.

Of course it will affect performance--opening and closing a connection takes time.

So, since your question was completely generic and provided zero useful information, the answer is "it depends". Sure sounds like an interview question to me, since you're not asking anything specific.

Create a connection pool and get and close a connection.

Sorry to resurrect an old thread. I'm new here and the sort is all screwed up. Should be sorted by date..or at least thats what Im used to.

Don't worry - this isn't an old thread

I would say that connection pools are probably overkill for single user desktop applications. You are only ever likely to need one connection there.

Yeah I was looking at the wrong date. Will take me a little while to get used to this place.

I thought the question was for web / desktop in that case I thought it meant for web and/or desktop.