how do I create unique constraints on two properties in neo4j?

Question

I'm using nodes as intermediate path elements, but I want to make sure the start/end are unique. How do I create a constraint that requires TWO values to be checked?

I can set individual ones but can't see syntax for a two-part constraint.

        neolib.run_query(
            """CREATE CONSTRAINT
                uSource
                if not exists
                ON (m:route) ASSERT m.source IS UNIQUE""")
        neolib.run_query(
            """CREATE CONSTRAINT
            uTarget
            if not exists
            ON (m:route) ASSERT m.target IS UNIQUE""")

Answer 1

It has this documentation:

https://neo4j.com/docs/cypher-manual/current/administration/constraints/#query-constraint-node-key

CREATE CONSTRAINT [constraint_name] [IF NOT EXISTS]
ON (n:LabelName)
ASSERT (n.propertyName_1,
n.propertyName_2,
…
n.propertyName_n)
IS NODE KEY
[OPTIONS "{" option: value[, ...] "}"]

FOR EXAMPLE:
    CREATE CONSTRAINT uSourceTarget IF NOT EXISTS ON (m:route) ASSERT (m.source, m. target) IS NODE KEY

NB: Only applicable for Enterprise Edition (NOT community edition)