[Springframework-developer] Re: [Springframework-user] JdbcTemplate update example

[<jue...@we...>]

In the course of this change, I suggest two further minor changes:

- The "doWithResultSetFromXxx" methods should really be named "query", =
just with overloaded ResultSetExtractor arguments. There is no strong =
difference to the other "query" methods that take all sorts of argument =
combinations (particularly since the introduction of "queryForList" =
etc). I don't think that this renaming will cause hassle, as I suspect =
that hardly anyone uses those methods anyway.

- I don't think that the "update" method that takes a =
PreparedStatementCreator array is very helpful: It doesn't use batching =
or reuse Statement instances but just executes the created =
PreparedStatements one-by-one. I suggest to remove that overloaded =
method: Application code should simply invoke =
"update(PreparedStatementCreator)" for each statement. I guess that the =
PreparedStatementCreator array version is rarely used too, and the =
replacement is straightforward.

Juergen


-----Original Message-----
From: j=FCrgen h=F6ller [werk3AT]=20
Sent: Tuesday, March 16, 2004 3:39 PM
To: 'spr...@li...';
spr...@li...
Subject: Re: [Springframework-user] JdbcTemplate update example


Will, everyone,

Our current JdbcTemplate does indeed not cover such use cases: It rather =
assumes that each operation will use its own (Prepared)Statement =
instance.=20

Therefore, I've added further JdbcTemplate methods that take generic =
callback actions:
- execute(StatementCallback)
- execute(String sql, PreparedStatementCallback)
- execute(String sql, CallableStatementCallback)

Each of the callback interfaces has a single "Object =
doInStatement(Statement)"-style method, allowing for any number of =
operations to be performed on the passed-in statement.

There also overloaded versions that take statement creators:
- execute(PreparedStatementCreator, PreparedStatementCallback)
- execute(CallableStatementCreator, CallableStatementCallback)

I've refactored all of JdbcTemplate's existing data access methods to =
use those generic execute methods with inner-class callback =
implementations: This has removed almost all internal code duplications =
that were necessary before.

I believe that this is an important addition: Reusing a statement =
instance for multiple executions with different parameters is a valid =
and quite common use case. And cleaning the JdbcTemplate internals is a =
nice side effect.

Awaiting your feedback! (I haven't committed that change yet, but intend =
to do so before the release this weekend.)

Juergen



-----Original Message-----
From: spr...@li...
[mailto:spr...@li...]On Behalf Of
Will Jaynes
Sent: Monday, March 15, 2004 8:10 PM
To: spr...@li...
Subject: [Springframework-user] JdbcTemplate update example


I'm converting some of my JDBC DAOs to Spring JdbcTempate usage. I'm=20
afraid I need an example of reusing a PreparedStatement over a number of =

updates. The update methods for JdbcTemplate all seem to create a=20
PreparedStatement, so perhaps I can't use any of them.

The old code looks something like:

public void doAnUpdate(Connection conn, String[] ids) {
...
ps =3D conn.prepareStatement("Update A set B =3D null where id =3D ?");
for (int i=3D0; i<ids.length; i++)
  ps.setString(id[i]);
  ps.executeUpdate();
}
...

Thanks for any help,
Will


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