So, is there any simple trick to tell grails/GORM/hibernate not to use the “version” column?

There’s a proposal for this feature in the Grails sandbox, so it’s quite possible that we’ll see something along these lines implemented eventually.

Thanks again,
Jason

thanks for the tutorial. It really helped me to get started with a legacy db. But (working with grails 0.5) it still does not work properly for my mysql database. As soon as I use your hibernate.cfg.xml with Person.hbm.xml for my domain class Person (just id, name and surname for testing) I get the following exception:

Server failed to start: org.mortbay.util.MultiException[org.springframework.beans.factory.BeanCreationException: Error c reating bean with name ‘transactionManager’: Cannot resolve reference to bean ’sessionFactory’ while setting bean proper ty ’sessionFactory’; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean wi th name ’sessionFactory’: Invocation of init method failed; nested exception is org.hibernate.MappingException: invalid configuration, org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘transactionManage r’: Cannot resolve reference to bean ’sessionFactory’ while setting bean property ’sessionFactory’; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name ’sessionFactory’: Invocation of i nit method failed; nested exception is org.hibernate.MappingException: invalid configuration, org.springframework.beans. factory.BeanCreationException: Error creating bean with name ‘transactionManager’: Cannot resolve reference to bean ’ses sionFactory’ while setting bean property ’sessionFactory’; nested exception is org.springframework.beans.factory.BeanCre ationException: Error creating bean with name ’sessionFactory’: Invocation of init method failed; nested exception is or g.hibernate.MappingException: invalid configuration]

Do you have any idea, why this happens? It does not seem to have anything to do with my domain class…?

Anyway, the only reason to use the hibernate files is, that I have no version column in my domain class table and so always get an exeption because of the missing column:

Caused by: com.mysql.jdbc.exceptions.MySQLSyntaxErrorException: Unknown column ‘this_.version’ in ‘field list’ at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:936) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2822) at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1536) at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1626) at com.mysql.jdbc.Connection.execSQL(Connection.java:3031) at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:943) at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1049) at org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:92) at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:186) at org.hibernate.loader.Loader.getResultSet(Loader.java:1778) at org.hibernate.loader.Loader.doQuery(Loader.java:662) at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224) at org.hibernate.loader.Loader.doList(Loader.java:2211) … 77 more

So, is there any simple trick to tell grails/GORM/hibernate not to use the “version” column?

Thanks for any help!

Bye, Torsten

The next thing that is driven me crazy is this: “Cannot get property: id on null object” whenever the id filed is left blank. This appears to be coming from : render(view:’create’,model:[employee:employee])

I tried various things… 1. Putting constraints in the Employee class: static constraints = { id(blank:false) id(matches:/[a-zA-Z]/) } 2. redisplay the view: if(params.id==”") { render(view:’create’) } Finally I just gave up and added: if (employee.id == “”) { redirect(action:create) } that has the effect of blanking out the data already entered but at least I avoid a stack trace. Obviously I am new at this so I’ll sign up on the nabble forum and post a question there.

Regards, Dennis

@Dennis,
Thanks for the kind feedback.

Does that mean that id is excluded from “employee.properties = params”?

Yes indeed. As of Grails 0.4, the id is excluded from the binding. For more info please see the following thread from the mailing list.

Cheers,
Jason

Very nice work. Thankyou. Followed the tutorial with v0.5. Had to add // Next line added for assigned key (i.e ) employee.id = params.id to EmployeeController save().

Does that mean that id is excluded from “employee.properties = params”?

Dennis

That was fast. Do you sleep?

I guess grails does not generate the schema by itself, like hibernate, does it? No problem though. Workarounds, like what you mentioned are available.

Yup, Chapter 8 of Groovy in Action is one of my source to create by own builder. Just wondering whether there are more detail information regarding it that you may have. No problem. I’ll continue with my experiment.

Thanks again. Very helpful.

Hamdi

@Hamdi,

My usage scenarios for wanting the db schema itself, instead of Grails generating the db tables directly into the DB are: 1. For me to do any manual changes once, instead of going to the DB everytime (Dev DB, Test DB, Production DB). I prefer to change, tune it, etc, once, and use the db schema for all stages. 2. For me to submit to my DBA.

Ah. I think see what you mean now. If you're wanting just to tweak the database schema that Grails creates, you can try the following steps.

1. Let Grails create the tables for you in your dev schema.
2. Go into the database and make your adjustments.
3. Comment out the dbCreate property in all of your grails-app/conf/*DataSource.groovy classes. (By doing so, Grails will no longer try to modify the schema in any way.)
4. Export the DDL for your schema, and you (or your DBA) can use the DDL to create the schemas for your other enviroments.

Where can I get details on creating Builders?

I recommend taking a look at Chapter 8 of Groovy in Action.

I hope this helps.

Cheers,
Jason

Thanks for the fast reply!

My usage scenarios for wanting the db schema itself, instead of Grails generating the db tables directly into the DB are: 1. For me to do any manual changes once, instead of going to the DB everytime (Dev DB, Test DB, Production DB). I prefer to change, tune it, etc, once, and use the db schema for all stages. 2. For me to submit to my DBA.

One last question please. Where can I get details on creating Builders? I am extremely interested in DSL. I am experimenting with builders now but can’t find any details to it. My source for information so far are from the groovy website, books (more on using builders) and grails builders (source code for Hibernate Criterion Builder, etc).

Sorry for soo many questions for a groovy/grails newbie. Thanks again for your help.

Hamdi

@Hamdi,

Great article and great ebook! A pity it’s a bit out dated. Grails is really moving fast.

Thanks for the kind words. Grails is indeed progressing quickly, and this post is admittedly due for an update.

However, as of now, you should still find the e-book to be quite relevant and far from outdated. Be sure to check out the FAQ and the latest source code to pick up any changes between Grails 0.3.1 (the current Grails release when the book was published) and Grails 0.4.2 (the current Grails release as of today).

1. Is there a way to generate the hbm files from Grails, much like in hibernate?

There was some discussion on this topic on the Grails mailing list that you may find helpful.

http://www.nabble.com/Re%3A-Hibernate-mappings%2C-sequences%2C-etc.-p8967184.html

On a similar note, the Grails roadmap includes future support for generating the domain model from the database.

2. For normal Grails usage, nor [sic] using legacy db, is there a way to generate the db schema, also like hibernate?

By default, Grails will indeed generate the database tables for you. See the dbCreate option in grails-app/conf/*DataSource.groovy.

I hope this helps.

Cheers,
Jason

Great article and great ebook! A pity it’s a bit out dated. Grails is really moving fast.

Some questions from a newbie: 1. Is there a way to generate the hbm files from Grails, much like in hibernate? 2. For normal Grails usage, nor using legacy db, is there a way to generate the db schema, also like hibernate?

Sorry if asking here is inappropriate. Not sure where to ask really.

Thanks,

Hamdi