Opening db connections

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Eduardo Yáñez Parareda - 13 Nov 2007 08:52 GMT

Hi,

when the connection to a DB is open, when you get the Statement or when you execute it?

ie.:

Statement stmt = StatementProvider.getStatement();
ResultSet rs = stmt.executeQuery("select 1");
rs = stmt.executeQuery("select 1");
rs = stmt.executeQuery("select 1");

Does this code mean 3 opened connection or only one (getStatement)?

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Lew - 13 Nov 2007 13:35 GMT

> when the connection to a DB is open, when you get the Statement or when
> you execute it?

When you issue a DriverManager.getConnection(), typically, or via the
javax.persistence.EntityManager class.

> ie.:
>
[quoted text clipped - 4 lines]
>
> Does this code mean 3 opened connection or only one (getStatement)?

It's no more than one, but not being familiar with the StatementProvider class
it's hard to be sure.

What is StatementProvider?

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Lew

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Eduardo Yáñez Parareda - 13 Nov 2007 14:17 GMT

> It's no more than one, but not being familiar with the StatementProvider
> class it's hard to be sure.
>
> What is StatementProvider?

I'm sorry, it's a class of my project, I didn't realize of that.

This is what I meant:

Connection conn = .... getConnection...

Statement stmt = conn.getStatement();
ResultSet rs = stmt.executeQuery("select 1");
rs = stmt.executeQuery("select 1");
rs = stmt.executeQuery("select 1");

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Lew - 13 Nov 2007 14:31 GMT

Lew wrote:

>> What is StatementProvider?

> I'm sorry, it's a class of my project, I didn't realize of that.
>
[quoted text clipped - 6 lines]
> rs = stmt.executeQuery("select 1");
> rs = stmt.executeQuery("select 1");

You have as many connections as conn points to.
<http://java.sun.com/javase/6/docs/api/java/sql/DriverManager.html#getConnection(
java.lang.String)>

<http://java.sun.com/javase/6/docs/api/java/sql/Connection.html>

and, of course, the Javadocs for ResultSet and Statement.

BTW, consider using a PreparedStatement instead of a "regular" Statement.

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Lew

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Opening db connections

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