how to implement soft deletes

Question

Can anyone tell me what would be a good way to implement soft deletes? I can have a deleted property in my class, but my question is how to easily ignore instances which have deleted = true in my searches, listings and so on.

So, rather than saying Domain.findByDeleted(true) just get Domain.list() to ignore deleted instances, rather than saying Domain.findByPropertyAndDeleted('property', true) just say Domain.findByProperty('property').

Is there a nice way of doing this?

This should help you out : http://stackoverflow.com/questions/8768534/grails-update-instead-of-delete/8768728 — Anuj Arora, Jan 19 '12 at 19:35

score 8 · Accepted Answer · answered Jan 19 '12 at 00:50

8

I would recommend using a named query for this. Something like

static namedQueries = {
    notDeleted {
        ne 'deleted', true
    }
}

which you could use like Domain.notDeleted.list() or Domain.notDeleted.findByProperty(value)

answered Jan 19 '12 at 00:50

doelleri

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score 1 · Answer 2 · answered Jan 19 '12 at 10:16

1

The hibernate filter plugin can automatically add the predicate deleted = false to every query that is performed for a particular domain class. However, my testing indicated that this plugin does not work with Grails 2.0.0.

answered Jan 19 '12 at 10:16

Dónal

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score 0 · Answer 3 · answered Jan 19 '12 at 07:52

0

We're used to override list(), get() and some more methods of domain classes. Now we can use syntax like A.delete(log: true)

On bootstrap, we do:

grailsApplication.domainClasses.each { GrailsDomainClass domainClassInfo ->
    def oldGormDelete = domainClassInfo.metaClass.getMetaMethod('delete', [] as Class[])
    assert oldGormDelete
    domainClassInfo.metaClass.delete = { Map params ->
        ...
        def result = oldGormDelete.invoke(delegate)
        ...
    }
}

answered Jan 19 '12 at 07:52

Victor Sergienko

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This is the second time I've come across this strategy. I'm not too familiar with grails meta programming, Could you please explain what is going on here, invoking delegate? – gotomanners Jan 19 '12 at 13:06
1

I'm using Groovy metaprogramming (see http://groovy.codehaus.org/JN3525-MetaClasses, "ExpandoMetaClass" section). In Class' `metaClass` property I'm assigning closures to be called instead of certain method signatures, in the example - static `delete(Map params)` method. `delegate` is a Groovy keyword like `this` and `owner`, meaning the object the closure is called as a method of - see http://groovy.codehaus.org/Closures. `invoke()` is, er, `Closure`'s method to execute it with a given `this` and given list of arguments - the parameters after first one will be used as call arguments. – Victor Sergienko Jan 19 '12 at 15:26

how to implement soft deletes

3 Answers3