JPA alternatives?

[Jens]

In a current project I use JPA for persistence. JPA works and you can have a fast start with it but it has its pitfalls. 

For example having lazy attributes sounds nice but as soon as you have more complex logic and queries you want to fetch these properties eagerly to avoid hundreds of querys (N+1 for collections). But you can not make everything eagerly because then simple queries would fetch lots of data that is not needed at all. So you have to use JOIN FETCH but thats not defined for multiple tiers/properties in the JPA spec. So you end up using vendor specific features and its not that nice anymore to use JPA. 

Also if anything gets wrong with your queries its hard to debug the internals of JPA.

So I wonder if there are any nice alternatives to JPA? 

What do you guys use for persistence assuming you can not use AppEngine and thus Objectify? 

-- J.

[Juan Pablo Gardella]

jdbc

2011/9/12 Jens <jens.ne...@gmail.com>

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[Y2i]

When you use JDBC, what do you use to map between the database records and Java objects?  Also, what do you do to deal with optimistic concurrency control?  JPA automatically uses versioning.  Do you have to implement the same mechanism by hand or are there tools that help with this?

[J.Ganesan]

If I may suggest, please try out DataStoreGwt. It does lazy loading,
enables optimistic concurrency control from client side and does
automatic versioning of objects.

J.Ganesan
www.DataStoreGwt.com

[Paul Stockley]

Take a look at mybatis

[Thomas Broyer]

Never used them, but Spring's JdbcTemplate with RowMapper, and MyBatis seem appealing (for the ORM part; AFAIK, versionning has to be done by hand, but I suspect this is by design)

[Y2i]

Does DataStoreGwt support WITH RECURSIVE sql features?  I need to efficiently traverse large graphs within the database before returning small result sets as opposed to returning large result sets and traversing them on either client or server.

[Y2i]

Thanks Thomas, these look interesting.

[Jens]

Haven't looked into it in detail but I think it doesn't match my needs. I can not use an embedded database on server side (clustered application server / database environment).

[Juan Pablo Gardella]

If you wan't have problem with lazy loading, N+1; you must write a custom jpaql query to fetch the properties do you need. You have N queries, so q1 fetch X properties, q2 Y properties. This is the way I found to resolve the problems that you mark with JPA.

Always you will final must tunning your queries when have a lot of data.

Juan

2011/9/12 Juan Pablo Gardella <gardella...@gmail.com>

[Jens]

Thanks I'll take a look at it. Hopefully I can dynamically set a DataSource to mybatis and don't have to configure them statically in xml.

-- J.

[Ashton Thomas]

I use Spring/JDBC/MyBatis

Like it so far

[Y2i]

How do you debug your application?  For production I use the same version of Jetty that comes with GPE, so I can debug my application (both server and client) without changing any configuration and without going through GWT re-compilation.  Is it possible to do the same when using Spring container?

[Paul Stockley]

That should be possible. I also use mybatis generator to generate all the maps/dto's. I created a plugin because I needed to customize the code generated to support GWT RPC plus some application specific stuff. It would be pretty easy to add optimistic locking automatically.

[yur...@gmail.com]

Thanks Paul.  I'm currently sticking with Jetty+JPA but Spring and MyBatis is something I'd like to look into if it is possible to setup debugging without GWT re-compilation.

On Mon, Sep 12, 2011 at 7:43 PM, Paul Stockley <pstoc...@gmail.com> wrote:

That should be possible. I also use mybatis generator to generate all the maps/dto's. I created a plugin because I needed to customize the code generated to support GWT RPC plus some application specific stuff. It would be pretty easy to add optimistic locking automatically.

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[maticpetek]

Last three year we are using iBatis and MyBatis with GWT project and we are very happy with it. Just must be a programmer that loves writing SQL.. 

Regards,

   Matic

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