Why are properties with unique index required?

Hello I have a problem with unique index properties being required.

I have a class that is essentially:

class Class(neomodel.StructuredNode)
    title = neomodel.StringProperty(required = True)
    fileName = neomodel.StringProperty(required = True, unique_index = True)
    id = neomodel.IntegerProperty(required = True)
    otherProperty = neomodel.StringProperty(required = False)
    anotherProperty = neomodel.StringProperty(required = False)
    otherId = neomodel.StringProperty( required = False, unique_index = True )

Note the otherId that is not required, but should be unique. When I run an update on my script some the new data is new nodes and some of the data is fileName changes for existing nodes. I am on the fence about whether I want to update the existing nodes or to make new nodes and change the otherId on the oldNodes so they don’t conflict.

The way I was planning on doing this is making a list of dictionaries with the title, fileName, id set but not the otherProperty. Then call models.Class.get_or_create(*list). After which I could go update all the existing nodes to replace their otherId’s with a new string like otherId.old.

I am having a problem with this because I get an exception for RequiredProperty(). I looked at the neomodel source code where the exception is being generated and it looks to me like it will be raised if a property with a unique_index is not set. Is this correct? Why are unique_index’s required? Why can I not call get_or_create with objects missing a property where required is false?

@classmethod
   def deflate(cls, obj_props, obj=None, skip_empty=False):
       # deflate dict ready to be stored
       deflated = {}
       for key, prop in cls.defined_properties(aliases=False, rels=False).items():
           # map property name to correct database property
           db_property = prop.db_property or key
           if key in obj_props and obj_props[key] is not None:
               deflated[db_property] = prop.deflate(obj_props[key], obj)
           elif prop.has_default:
               deflated[db_property] = prop.deflate(prop.default_value(), obj)
           elif prop.required or prop.unique_index:
               raise RequiredProperty(key, cls)
           elif skip_empty is not True:
               deflated[db_property] = None
       return deflated

Thank you very much for your help and I hope this was clear

[bhalbert]

I read the documentation you linked to and I can’t find anything saying that unique properties are required.

In the example below there is a constraint for ‘uid’ to be unique. I create a node that had no ‘uid’ and return it therefore Neo4j does not require unique properties to be non-null

[jonadaly]

@robinedwards @aanastasiou Please could we reopen this issue? This behaviour of neomodel directly contravenes the documentation - to quote the docs linked above:

https://neo4j.com/docs/cypher-manual/current/schema/constraints/

Unique property constraints ensure that property values are unique for all nodes with a specific label. Unique constraints do not mean that all nodes have to have a unique value for the properties — nodes without the property are not subject to this rule.

As @yarmash comments above, the solution is very simple. I am happy to raise a PR for this change if it would help?