py2neo（Neo4j）自动增加属性？

Question

I'm using flask with py2neo for my Rest service , I have a user node with the label "User".

how to autoincrement id for the "User" label , in neo4j using py2neo?

Answer 1

You don't, and you probably shouldn't. Neo4j already provides an internal id field that is an auto-incrementing integer. It isn't a property of the node, but is accessible via the id() function, like this:

MATCH (n:Person)
RETURN id(n);

So whenever you create any node, this already happens automatically for free by neo4j, and isn't done by py2neo.

If you need a different type of identifier for your code, I'd recommend something that's plausibly globally unique, like a UUID which is very easy to do in python, rather than an auto-incrementing integer.

The trouble with auto-incrementing numbers as IDs is that since they have a pattern to them (auto-incrementing) people come to rely on the value of the identifier, or come to rely on expectations of how the ID will be assigned. This is almost always a bad idea in databases. The sole purpose of the identifier is to be unique from everything else. It doesn't mean anything, and in some cases isn't even guaranteed not to change. Avoid embedding any reliance on any particular value or assignment scheme into your code.

That's why I like UUIDs, is because their assignment scheme is essentially arbitrary, and they clearly don't mean anything -- so they don't tempt designers to do anything clever with them. :)