Grails Saving Object With Composite Key Throws Error

Question

So, my team has been having multiple issues while upgrading our existing app from Grails 1.3.7 to 2.1.0. The latest headache occurs when trying to save a domain class object that has a composite key based on two other domain objects.

We are hanging Grails on a legacy database which we cannot readily change, so all of the domain classes have custom mappings to hook up with it. Below is a quick, slimmed down version of the domain classes in question.

Class Product {
    Short prodKey
    String name
    static hasMany = [groupProduct: GroupProduct] 
   //Also includes mapping to legacy db and simple constraints
}

Class Group {
    Short groupKey
    String name
    static hasMany =[ groupProduct: GroupProduct] 
   //This domain class has several other mappings and variables, but they are not relevant
}

Class GroupProduct {
    Group group
    Product product
    Character indicator
    static belongsTo = [Product,Group]
    static mapping = {
        id composite: ["group", "product"]
        group lazy:false, column:"GROUP_KEY", joinTable:"GROUP"
        product lazy:false, column:"PROD_KEY", joinTable:"PRODUCT"
        version false
    }
   //Only constraint is indicator is Y or N
}

In the app a user is able to select multiple products for a group to turn on or off via a checkbox list. The parameters contain the groupKey and a list of all checked products. The controller gets an instance of the specified group and then a list of all Products. The products are matched against the list in the parameters, every time a match is found a GroupProduct object is made with the indicator set to 'Y', otherwise a GroupProduct object is made with the indicator set to 'N'.

Class GroupProductController{
    //allowedMethods and other actions...
    def update = {
        def groupInstance = Group.get(params.GroupId)
        def groupProducts= []
        def products= Products.list()
        products.each{
          def indicator = ...//code to get value of check box for this Product. Returns either Y or N, works as expected
          def groupProduct= new GroupProduct(group:groupInstance ,
            product:it,
            indicator: indicator)
          groupProducts.add(groupProduct)  
        }

        groupInstance.discard()
        groupProducts.each{
          it.save(failOnError: true, flush:true)//This line throws a DB2 SQL error. SQLCODE=-407        
        }
    }
}

Resulting error is:

org.hibernate.util.JDBCExceptionReporter|DB2 SQL Error: SQLCODE=-407, SQLSTATE=23502, SQLERRMC= , DRIVER=3.50.152
org.codehaus.groovy.grails.orm.hibernate.events.PatchedDefaultFlushEventListener|Could not synchronize database state with session
org.hibernate.exception.ConstraintViolationException: could not update: [GroupProduct#component[group,product]{product=Product#1, group=Group#938926168}]
at com.controllers.ProductGroupController$_closure2_closure8.doCall(ProductGroupController.groovy:86)
at com.nationwide.nas.beam.controllers.ProductGroupController$_closure2.doCall(ProductGroupController.groovy:79)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:722)
Caused by: com.ibm.db2.jcc.b.lm: DB2 SQL Error: SQLCODE=-407, SQLSTATE=23502, SQLERRMC= , DRIVER=3.50.152
at com.ibm.db2.jcc.b.wc.a(wc.java:575)
at com.ibm.db2.jcc.b.wc.a(wc.java:57)
at com.ibm.db2.jcc.b.wc.a(wc.java:126)
at com.ibm.db2.jcc.b.tk.b(tk.java:1593)
at com.ibm.db2.jcc.b.tk.c(tk.java:1576)
at com.ibm.db2.jcc.t4.db.k(db.java:353)
at com.ibm.db2.jcc.t4.db.a(db.java:59)
at com.ibm.db2.jcc.t4.t.a(t.java:50)
at com.ibm.db2.jcc.t4.tb.b(tb.java:200)
at com.ibm.db2.jcc.b.uk.Gb(uk.java:2355)
at com.ibm.db2.jcc.b.uk.e(uk.java:3129)
at com.ibm.db2.jcc.b.uk.zb(uk.java:568)
at com.ibm.db2.jcc.b.uk.executeUpdate(uk.java:551)
at org.apache.commons.dbcp.DelegatingPreparedStatement.executeUpdate(DelegatingPreparedStatement.java:105)
... 5 more

The error occurs when trying to save the GroupProduct objects. According to IBM the error code -407 is caused by AN UPDATE, INSERT, OR SET VALUE IS NULL, BUT THE OBJECT COLUMN column-name CANNOT CONTAIN NULL VALUES . However, none of the variables for the GroupProducts are actually null. The Group and Product instances are pulled straight from the database, which means they have already been validated and shouldn't have any constraint violations, and I can see that the indicator field is being set correctly.

There is also no problem when running this code under the original 1.3.7 version of the project. If anyone could shed some light on this I'd be very grateful. Thanks

Answer 1

After much debugging and hunting through code, I managed to find the issue. All of our domain classes extend an abstract base domain, which has a createdTimestamp and updatedTimestamp field. Before doing an insert we set both fields, and before doing an update we update the updatedTimestamp .

The issue was that when we were saving, the new object had a null createdTimestamp field, which was throwing the error. Added in code to check if the GroupProduct object we were making already existed, and if so set the new objects createdTimestamp field to the existing object's before saving. Now everything works as expected.

Its strange that Grails 1.3.7 did not have any issues with this code, though. Only thing I can figure is that it automatically associated the new objects with existing ones in the DB. Probably the strangest behavior change I've found during the upgrade process. Hope this helps anyone running into a similar issue.