CODEWITHSUNDEEP
neo4jcypher
AJcodez
AJcodez

Reputation: 34206

neo4j how to drop all constraints

Is there a cypher command to drop all constraints?

I know I can drop specific constraints.

DROP CONSTRAINT ON (book:Book) ASSERT book.isbn IS UNIQUE

However I want to clear all constraints as part of teardown after testing. Can't find anything in the docs, but something like:

DROP CONSTRAINT *

Update: My testing setup.

Writing a tiny promise-based nodejs cypher client. I want to test defining unique indexes in application code.

Upvotes: 29

Views: 20322

Answers (8)

Graham Lea
Graham Lea

Reputation: 6333

I know the OP is asking about doing this programatically in testing, and this answer doesn't really satisfy that scenario. But if you're just looking to quickly delete all your constraints quickly without writing a program, you can generate a list of DROP CONSTRAINT commands using this query:

CALL db.constraints() YIELD name
RETURN "DROP CONSTRAINT " + name + ";";

Then you can quickly remove the pipes from the output and paste it back into cypher-shell to drop them all. It would probably be pretty easy to script that up with a shell script if it was something you wanted to do often.

Upvotes: 2

iamvarol
iamvarol

Reputation: 21

First of all, you have to create Neo4j class for connection:

class Neo4jConnection:
    
    def __init__(self, uri, user, pwd):
        
        self.__uri = uri
        self.__user = user
        self.__pwd = pwd
        self.__driver = None
        
        try:
            self.__driver = GraphDatabase.driver(self.__uri, auth=(self.__user, self.__pwd))
        except Exception as e:
            print("Failed to create the driver:", e)
        
    def close(self):
        
        if self.__driver is not None:
            self.__driver.close()
        
    def query(self, query, parameters=None, db=None):
        
        assert self.__driver is not None, "Driver not initialized!"
        session = None
        response = None
        
        try: 
            session = self.__driver.session(database=db) if db is not None else self.__driver.session() 
            response = list(session.run(query, parameters))
        except Exception as e:
            print("Query failed:", e)
        finally: 
            if session is not None:
                session.close()
        return response

After that create a connection:

uri = 'uri'
pwd = 'pwd'
user= 'user'

conn = Neo4jConnection(uri=uri, user=user , pwd=pwd)

And, you can run the below to delete all constraints:

## drop all constraints
const = conn.query("CALL db.constraints")

for c in const:
    conn.query(f"DROP CONSTRAINT {c['name']}")

Upvotes: 1

Matt Brandt
Matt Brandt

Reputation: 599

If you use node/javascript you can do something like:

const { records } = await cypher(`CALL db.constraints`)
await Promise.all(records.map(record => {
  cypher(`DROP CONSTRAINT ${record.get('name')}`);
}));

Upvotes: 2

Sam
Sam

Reputation: 4090

Here is a helper for those using neo4jrb gem:

class MigrationHeper
  include Neo4j::Migrations::Helpers
  def drop_all
    execute("match (n) detach delete n;")
    execute("call db.constraints").each do |constraint|
      execute "drop " + constraint[:description]
    end
  end
end

Upvotes: 0

meawoppl
meawoppl

Reputation: 2802

Here is how I do this in Python:

    s = connection.get_session()

    # Drop constraints / indices
    for constraint in s.run("CALL db.constraints"):
        s.run("DROP " + constraint[0])

Feels a bit icky, I feel like constraints should be a better supported thing.

Upvotes: 7

John
John

Reputation: 913

Note using APOC you can drop all indexes and constraints via CALL apoc.schema.assert({}, {}).

Upvotes: 46

subvertallchris
subvertallchris

Reputation: 5482

You can get a list of all indexes and constraints through GET requests to http://localhost:7474/db/data/schema/constraint/ and http://localhost:7474/db/data/schema/index. Here's how I do it in Ruby, maybe it'll give you an idea of how to do the same in Node.

c.after(:all) do
  conn = Faraday.new(url: "http://localhost:7474")
  response = conn.get('/db/data/schema/constraint/')
  constraints = JSON.parse(response.body)
  constraints.each do |constraint|
    Neo4j::Session.query("DROP CONSTRAINT ON (label:`#{constraint['label']}`) ASSERT label.#{constraint['property_keys'].first} IS UNIQUE")
  end 

  response = conn.get('/db/data/schema/index/')
  indexes = JSON.parse(response.body)
  indexes.each do |index|
    Neo4j::Session.query("DROP INDEX ON :`#{index['label']}`(#{index['property_keys'].first})")
  end
end

Upvotes: 7

Stefan Armbruster
Stefan Armbruster

Reputation: 39925

The only way to drop constraints is doing this on a per-constraint level. You can use e.g. :schema in the Neo4j browser to get a list of all constraints. I'd just write a short script for this.

Upvotes: 1

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