How does the SQL connection in an application should be called?
Back to basics.
I have an application written in c# and I am using the sqlC开发者_C百科lient to connect to database.
I have several methods and I usually open the connection in a try catch block
try{
**open connection**
//Mehod1()
//Method2()
........
}catch(exception){
//Do something
}finally{
**close connection**
}
The Problem is that there are a lot connections in pool.
I am using master page and in master page I am loading the menu from database (different menu for each user).
Then in main pages I open again a connection to get the rest data.
In the middle of the page it may be a method that need again to connect to database.
My Question is
Is this a good practise?
Am I doing something wrong?
Is there a better practise to avoid multiple connections? What about singleton pattern?
Thanks in advance
SOLUTION
I found the reason!!!
I had forgot to close a connection.
I was sure that I had close it, but sometimes you can't be so sure.
Thanks everyone for your responses
Since the connection is pooled you don't need to "reuse" it in different methods.
I use the following code:
using(SqlConnection connection = new SqlConnection("your-connectionstring"))
{
// Do your stuff here...
}
Using
is just a short hand way of writting try-catch-finally
. It is used for disposable objects.
And this can go into each method.
EDIT: Using the connection from the pool is not hurting performance either. All connection information are cached anyway. So just use the SqlConnection on an atomic level.
It's a good thing though to have the ConenctionString handling in a more generic way...
Using() as said above is a good way to new up a new object of a class that implements IDisposable. But with that being said , you cannot leave you connection open once you done. You have finite number of connection in the pool and leaving a connection unclosed can starve other SPIDs which are waiting for active connection which will finally timeout. So you should
- Always have atomic and small transactions .
- Close when done.
There is DAAB (data access application block) from Microsoft Enterprise Library which can be used as helper to open and close connections + do many other DB related tasks easily. Here it is http://msdn.microsoft.com/en-us/library/cc511547.aspx
Probably you didn't dispose your SqlConnections try this:
using (SqlConnection connection = new SqlConnection(connectionString))
{ }
this syntax will call method Dispose()
automatically for you. Using statement details here
UPDATE:
A bit more info about this methods you may find here: Close, Dispose
Basically the difference is that method Dispose()
called method Close()
, but before it is cleaning some resources and removing connection from the pool details here.
As you see Dispose()
doing a bit more than Close()
. So if you going to reuse connection later use method Close()
if not destroy that completely using method Dispose()
which is automatically getting called if you using the syntax above.
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