in 1.1 these hybrids will have the class_ attribute like other attributes.
Until then you can probably add your own class_ attribute to the object
which you are returning. Also, using a custom Comparator class (see
the example in the hybrid docs) will also return an instrumented
attribute that should have a class_ attribute.
Or you could try using the 1.1 hybrid_property class yourself, it should
be compatible with 1.0. The commits are illustrated in
https://bitbucket.org/zzzeek/sqlalchemy/issues/3653 but you can probably
just use the hybrid.py straight from the git repository with 1.0.
On 05/10/2016 02:01 PM, Brian Cherinka wrote:
I'm trying to build a query system where given a filter parameter name,
I can figure out which DeclarativeBase class it is attached to. I need
to do this for a mix of standard InstrumentedAttributes and Hybrid
Properties/Expressions. I have several Declarative Base classes with
hybrid properties / expressions defined, in addition to the standard
InstrumentedAttributes from the actual table.
mydb.dataModelClasses.Cube for example.
For a standard attribute, I can access the class using the class_ variable.
Standard Attribute on the DeclarativeBase class Cube
|
type(datadb.Cube.id)
sqlalchemy.orm.attributes.InstrumentedAttribute
printdatadb.Cube.id.class_
mydb.DataModelClasses.Cube
|
What's the best way to retrieve this same information for a hybrid
expression? My expressions are other types, thus don't have the class_
attribute. One example of my hybrid property defined in the Cube class
|
@hybrid_property
defplateifu(self):
return'{0}-{1}'.format(self.plate,self.ifu.name)
@plateifu.expression
defplateifu(cls):
returnfunc.concat(Cube.plate,'-',IFUDesign.name)
|
|
type(datadb.Cube.plateifu)
sqlalchemy.sql.functions.concat
|
Since this property is now a function concat, what's the best way to
retrieve the name of the class that this property is attached to, namely
'mydb.DataModelClasses.Cube'? It doesn't seem to have a .class_ or
.parent attribute. Is there a way to add a new attribute onto my hybrid
columns that let me access the parent class?
I need to do this for a variety of hybrid properties/expressions, that
are all constructed in unique ways. This particular example is a
function concat, however I have others that are of type
sqlalchemy.sql.elements.BinaryExpression.
Is there a way to generically do this no matter the type of hybrid
expression I define?
Thanks.
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