PHP(?) question

R_J

I guess it is a general PHP question, but it might as well be Vanilla related: why is there sometimes $UserModel = Gdn::UserModel(); and on other places $UserModel = new UserModel(); used? Is one of them to be preferred? Should I avoid one of both syntaxes do they differ in what is going on behind the scenes?

Linc

UserModel didn't use to have a static instance you could grab, so most of the time it's legacy code when we instantiate.

However, our models do get polluted, so it could also be done to make sure you have a clean copy, or to do something in parallel.

Generally speaking, I'd say grab the static copy.

hgtonight

$UserModel = Gdn::UserModel() is calling a static method of the Gdn class. It always returns the same instance of the UserModel. $UserModel = new UserModel() is calling the constructor of the UserModel class with no parameters and returning the instance generated.

The first method just gives you the (probably) already existing copy of the model while the second creates a completely separate copy.

If you need to modify the existing model, use the static call. If you are needing a separate object, you will want a new copy.

EDIT - crosspost

Linc

UserModel didn't use to have a static instance you could grab, so most of the time it's legacy code when we instantiate.

However, our models do get polluted, so it could also be done to make sure you have a clean copy, or to do something in parallel.

Generally speaking, I'd say grab the static copy.

hgtonight

$UserModel = Gdn::UserModel() is calling a static method of the Gdn class. It always returns the same instance of the UserModel. $UserModel = new UserModel() is calling the constructor of the UserModel class with no parameters and returning the instance generated.

The first method just gives you the (probably) already existing copy of the model while the second creates a completely separate copy.

If you need to modify the existing model, use the static call. If you are needing a separate object, you will want a new copy.

EDIT - crosspost

R_J

Oh, that's really a huge difference! Thanks for your answers, very informative!

rbrahmson

This is very informative @hgtonight , thanks!

Makes me wonder whether @R_J 's response to my question yesterday (How to retrieve the currently defined column names in a garden table) that "that if you work with Gdn::sql() you work with an existing instance of the sql class, so you might have "relicts" from a former sql call or even worse, you destroy the sql that should be built before/after your custom method is called" is an example of such case and that to have a separate sql access thread one need to create a new sqlmodel instance... I'm not sure how to though.

Hope I don't confuse unrelated concepts...

hgtonight

Yes, you are using the same object twice. You shouldn't need to use the SQLDriver object unless you are writing a model (or extending it).

rbrahmson

Thanks! I think I am starting to "get" Vanilla;-)