MappedManyToMany overwrite strategy

[alexmnyc]

Guys,

What is the best practice strategy for overwriting a MappedManyToMany?

Thanks,

Alex

[Diego Medina]

what do you mean?

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Diego Medina
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[alexmnyc]

As in 

class Model extends ManyToMany{

     object mtmField extends MappedManyToMany(this, OtherModel)

}

then if we have an instance of a model we are editing somewhere else:

var newValues:List[OtherModel] = List(.....)

//is this enough to guarantee that the new list "newValues" will overwrite mtmField?

model.mtmField.delete_?

model.mtmField.++= newValues:List

model.save

[Diego Medina]

I'm pretty sure that it will, it will definitely run in the same sql transaction, so it there is a problem, the whole thing would fail and let you know, instead of doing the delete but not the adding new values.

for the second line, doesn't this work:

model.mtmField(newValues)   

?

instead of .++= 

Thanks

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[a.mik...@gmail.com]

Getting:

[error]  found   : List[code.model.OtherModel]
[error]  required: Int
[error]     fee.mtmField(a)

where a  is  of type List[OtherModel]

[Diego Medina]

ah, right, sorry, I was thinking of a OneToMany, but you have a ManyToMany,sorry about that, your original code is fine then

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[a.mik...@gmail.com]

By the way,

.delete_? was acting funky, it would not add all items to the join table so I ended up using

mtmField.clear()

mtmField ++= List[OtherModel]

[Diego Medina]

thanks for posting your latest code

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[a.mik...@gmail.com]

My pleasure.

I haven’t tested it with long lists yet. I will update the thread if I run into any oddities with this approach.

[Diego Medina]

great, and if you do run into issues, please post a sample project following these steps:
https://www.assembla.com/wiki/show/liftweb/Posting_example_code

so I have something to test out while trying to help you.

Thanks

Diego

On Fri, Mar 13, 2015 at 10:10 PM, <a.mik...@gmail.com> wrote:

My pleasure.

I haven’t tested it with long lists yet. I will update the thread if I run into any oddities with this approach.

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