My database class

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craigclister@yahoo.co.uk - 15 Jan 2008 17:24 GMT

I'm writing a small 'learning' app. It uses SQL Server.

I am trying to create a common class of database functions. So, am I
right in saying that it should be a static class? I've done that, but
then I can't declare a private class variable, because the class is
static...

internal static class Database
{
internal SqlConnection conn = new SqlConnection(); <---
Error...

internal static bool Connect()
{
try
{
conn.ConnectionString = "Data Source=localhost;
Integrated Security=SSPI; Initial Catalog=HomeShopper";
conn.Open();
return true;
}
catch(Exception e)
{.................................

How should I be doing this? I'd like to then be able to:

Common.Database.Connect();

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Jon Skeet [C# MVP] - 15 Jan 2008 17:46 GMT

> I'm writing a small 'learning' app. It uses SQL Server.
>
[quoted text clipped - 23 lines]
>
> Common.Database.Connect();

Well, to do that you could make conn static (preferrably private, too)
- but maintaining a single static connection isn't a generally good
idea. It's better to open the connection when need it, and close it
immediately after you've used it, e.g. in a using statement.

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Jon Skeet - <skeet@pobox.com>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
World class .NET training in the UK: http://iterativetraining.co.uk

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craigclister@yahoo.co.uk - 15 Jan 2008 19:06 GMT

> It's better to open the connection when need it, and close it
> immediately after you've used it, e.g. in a using statement.

Thanks (again) John. Can you give an example of the Using?
I guess you mean if I have a 'getData' type function which I pass an
SQL statement to, and returns a recordset, then the getData would open
the connection, do the query, return the data and close the connection?

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Jon Skeet [C# MVP] - 15 Jan 2008 21:10 GMT

> > It's better to open the connection when need it, and close it
> > immediately after you've used it, e.g. in a using statement.
>
> Thanks (again) John. Can you give an example of the Using?

The using statement is something like:

using (SqlConnection conn = new SqlConnection())
{
// Use conn here
}
// conn has automatically been closed (Dispose has been called) even
// if an exception is thrown

> I guess you mean if I have a 'getData' type function which I pass an
> SQL statement to, and returns a recordset, then the getData would open
> the connection, do the query, return the data and close the connection?

Exactly.

Signature

Jon Skeet - <skeet@pobox.com>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
World class .NET training in the UK: http://iterativetraining.co.uk

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Ignacio Machin ( .NET/ C# MVP ) - 15 Jan 2008 18:34 GMT

Hi,

If the class is static then it should contani only static members. Not only
that but that code should not compile and should give you an error that a
static class can only contains static members.

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Ignacio Machin
http://www.laceupsolutions.com
Mobile & warehouse Solutions.

> I'm writing a small 'learning' app. It uses SQL Server.
>
[quoted text clipped - 23 lines]
>
> Common.Database.Connect();

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My database class

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