Atomic update operations
Before v1.2.6, PlayMorphia user must resort to morphia interface to get atomic update operations done:
Datastore ds = Employee.ds();
UpdateOperations op = ds.createUpdateOperations(Employee.class);
UpdateOperations<Employee> op = ds.createUpdateOperations(Employee.class).inc("salary", 10000).inc("bonus", 99999);
Query<Employee> q = (Query<Employee>)Employee.q().findBy("department", "IT").getMorphiaQuery();
ds.update(q, op);
Now with new v1.2.6, you do it this way:
Employee.o().inc("salary, bonus", 10000, 99999).update("department", "IT");
Start from v1.2.10, one can do update operation on a specific entity model:
Account myAccount = Account.find("username", username);
myAccount._update("email", "[email protected]");
Before v1.2.10, you have to do the following for the same operation:
Account myAccount = Account.find("username", username);
myAccount.email = "[email protected]";
myAccount.save();
Compare with the new _update operation, the old one is much more heavy because it needs to serialize the entire model when saving the updates.
Start from v1.2.12, you can use _unset to set a field to null:
myAccount._unset("name,email");
And use _set to set non-null field values:
myAccount._set("name,email", "morphia", "[email protected]");
Start from v1.2.12, _update could be used to set mixed null and non-null values:
myAccount._update("name,email", "morphia", null);
However for better performance you want to do it this way:
myAccount.startBatchUpdates()._set("name", "morphia")._unset("email").commit();
Why atomic update operations
TBD.