Working directly at the JDBC level is really quick, particularly if
you use connection pooling. Apache's dbcp library has worked great
for me, and it's fairly easy to use (although configuration is a
little bit of a pain). Here's how I use it:
In your application, create a ConnectionPool (you can configure this
any way you want):
GenericObjectPool connectionPool = new GenericObjectPool(null);
connectionPool.setMaxWait((long)5000);
connectionPool.setWhenExhaustedAction
(GenericObjectPool.WHEN_EXHAUSTED_GROW);
connectionPool.setTimeBetweenEvictionRunsMillis(60000);
connectionPool.setMaxActive( 20);
connectionPool.setMaxIdle( 10);
connectionPool.setMinEvictableIdleTimeMillis( 60000 );
ConnectionFactory connectionFactory = new
DriverManagerConnectionFactory(url, username, password);
PoolableConnectionFactory poolableConnectionFactory = new
PoolableConnectionFactory
(connectionFactory,connectionPool,null,null,false,true);
dataSource = new PoolingDataSource(connectionPool);
To make sure all the connections close properly when the application
exits, I override _terminateOrResetTimer() as well:
public void _terminateOrResetTimer() {
try {
connectionPool.close();
} catch (Exception e) {
}
}
System.exit(0);
}
Finally, create a convenience method to get a connection from the pool:
public static Connection getConnection() {
try {
return dataSource.getConnection();
} catch (Exception e) {
NSLog.out.appendln(ErrorStackTrace.toString(e));
}
return null;
}
Now whenever you need to do things with the database, you just need
to get a connection from the pool, create a statement with it, and
then use that statement to execute your queries/updates:
Connection connection = null;
Statement statement = null;
ResultSet result = null;
try {
connection = Application.getConnection();
Statement statement = connection.createStatement();
String sql = "update something set something where
something";
ResultSet result = statement.executeQuery(sql);
if (!result.first()) {
sql = "select max(" + column + ")" + column + " from
" + table;
result = statement.executeQuery(sql);
result.first();
if (result.getInt(column) == 0) {
next = startValue;
} else {
next = result.getInt(column) + 1;
}
sql = "insert into something values('" + someValues +
"', 0)";
statement.executeUpdate(sql);
}
} catch (SQLException e) {
...
} finally {
try {
result.close();
statement.close();
// closing the connection frees it back to the
pool
connection.close();
} catch (SQLException f) {
...
}
}
This code is mostly from memory, so no guarantees, but I believe the
concepts are all right.
I find it kind of frustrating and poorly designed that for every
single thing you do throws a SQL exception that you either have to
throw yourself or handle in some way. I can appreciate the reasoning
behind it (database connection are probably more prone to fail than
most things), but in my experience, failure rarely occurs and it
makes coding a bit of a pain. You can write subclasses of
Connection, Statement, and ResultSet that handle the exceptions in a
consistent way if you like without having to catch exceptions all
over the place.
Hope this helps.
Mark
On May 25, 2007, at 9:59 AM, Guido Neitzer wrote:
On 25.05.2007, at 01:22, Ted Archibald wrote:
I have a webobjects accounts receivable application that I have a
batch utility that changes certain fields everynight. I'm having
issues with the speed of the batch utility and I suspect the
slowness is due to having to access the full EO.
Is there a way to change the value of a field in an EO WITHOUT
having access to the full EO? I know you can do this through a
stored procedure, but I would rather not do that. Is there a way
to do this in WebObjects?
In addition to what Kieran said:
You can also use raw SQL. Look at EOUtilities.rawRowsForSQL for
this. You can fetch raw rows, but you can also execute standard SQL
inserts or updates.
You can also go directly to the JDBC level and work there ...
cug
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Webobjects-dev mailing list ([email protected])
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/webobjects-dev/mark%
40bluecollarsoftware.com
This email sent to [EMAIL PROTECTED]
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Webobjects-dev mailing list ([email protected])
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com
This email sent to [EMAIL PROTECTED]
