How do you bulk delete records in Grails/GORM?
I have a table which has records that need to be periodically cleared according to a set of criteria.
I was expecting that I could use the criteria builder to just delete the records, but that fails because there is no delete
method on criteria...
def c = Agency.createCriteria()
c.delete
{
eq("agency", "XXX")
}
So I thought maybe I first query for the set and then delete that...
def c = Agency.createCriteria()
def deletions = c
{
eq("agency", "XXX")
}
deletions.delete
This also fails for the same reason, different object.
So what is the right way to do t开发者_JAVA百科his? It seems excessive (perverse) that I would have to iterate through the entire result set calling delete()
on each item.
I know I can form a query to execute directly either in HQL or SQL but that feels wrong too. Is the criteria builder only meant for retrieval?
Thanks
With Grails 2.0 you can use a detached query like this:
Agency.where { }.deleteAll()
Note that you don't get the listeners and whatnot executed, but it does execute through to the database, AND it is compatible with the mocked domain stuff, as in:
void testWhatever() {
mockDomain(Agency, [])
saveABunchOfAgencies() // saves 10 of 'em
assert Agency.count() == 10
Agency.where { }.deleteAll()
assert Agency.count() == 0 // Joy!
}
That being said the GORM unit test mocks have a bunch of gotchas but are in general pretty neat.
From the User Guide about deleting objects:
Note that Grails does not supply a deleteAll method as deleting data is discouraged and can often be avoided through boolean flags/logic.
If you really need to batch delete data you can use the executeUpdate method to do batch DML statements:
Customer.executeUpdate("delete Customer c where c.name = :oldName", [oldName:"Fred"])
If you want to avoid HQL I'd suggest using GORM list(), delete() and Groovy's spread operator:
def agencyList = Agency.createCriteria().list { eq("agency", "XXX") } agencyList*.delete()
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