Hi all,
I am trying to create a constraint on the property of a node.
CREATE (c:Car {name:'test1', type:'test1'})
I am trying to prevent a user from implementing the name and type property as the same string. (i.e name ≠ type) I also need both properties to be unique using query below.
CREATE CONSTRAINT car_property_1
ON (c:Car)
ASSERT (c.name,c.type) IS NODE KEY
Also on a curious note can I constraint two different properties on two different nodes to not equal each other also?
Hello @tarendran.vivekanand 
You can add two unique constraints:
CREATE CONSTRAINT car_property_1 ON (c:Car) ASSERT (c.name, c.type) IS NODE KEY
CREATE CONSTRAINT constraint_name ON (c:Car) ASSERT c.name IS UNIQUE
CREATE CONSTRAINT constraint_type ON (c:Car) ASSERT c.type IS UNIQUE
Regards,
Cobra
@Cobra Sorry my bad didnt double check. The solution you gave me still doesnt take into account whether the property cannot equal to each other. So I have use this query
CREATE (c:Car {name:'test1', type:'test1'})
I should get an error saying u cant set the name and test to be each other
Yeah your right 
my bad 
I don't think it's possible to make it directly but as said here in this topic, you can try their solution to solve your problem
Regards,
Cobra
Thanks anyways. Will just have to figure out another way. 
Did you try the solution given in the topic I linked you @tarendran.vivekanand?
However, I can think of a workaround that might be acceptable, depending on your use cases. Let's say you want properties a, b, and c to be unique as a group. You can add an extra property, d, that concatenates the stringified values of a, b, and c, using appropriate delimiter(s) to separate the substrings (such that, for example, the a/b delimiter is a character that never appears in a or b). You can then create a uniqueness constraint on d.
Wont work for me as that is inefficient and will be very costly once you have 100000+ nodes
Ah yeah I see, otherwise you can check before the creation if both properties are different
Yea. Will just have to solve this in FE somehow
You could take a look at APOC Triggers to see if they meet the need.
This will allow you to define a check pre-commit with a custom error message, for your example I think the following works
CALL apoc.trigger.add("checkNameType",
"UNWIND apoc.trigger.propertiesByKey($assignedNodeProperties, 'name') AS name
with name
UNWIND apoc.trigger.propertiesByKey($assignedNodeProperties, 'type') AS type
call apoc.util.validate(name.new = type.new, 'Entry invalid: name (%s) same as type (%s)',[name.new, type.new]) RETURN null", {phase:'before'})
With that enabled you will get an error when trying your CREATE .. statement from above