cq

cq - cypher queries for database/sql

A golang database/sql implementation for Cypher/Neo4j. I've released v1. I plan to change the API in the near future, but v1 will remain supported for some time.

If you'd like to use the new gopkg.in semantic versioning system:

import "gopkg.in/cq.v1"

status

getting help

thanks

Thanks to Baron, Mike, and Jason for the ideas/motivation to start on this project. Cypher is close enough to SQL that it seems to fit pretty well in the idiomatic database/sql implementation.

Other Go drivers for Neo4j that support Cypher

• Neoism (a careful/complete REST API implementation)
• GonormCypher (a port of AnormCypher, to get up and running quickly)
• neo4j-go (Jake's experimental Cypher driver)

usage

See the excellent database/sql tutorial from VividCortex, as well as the package documentation for database/sql for an introduction to the idiomatic go database access.

You can (and should) use parameters, but the placeholders must be numbers in sequence, e.g. {0}, {1}, {2}, and then you must put them in order in the calls to Query/Exec. If you'd like to use named parameters, you can use the sqlx library along with cq. Please let me know if any issues arise from using sqlx with cq--it is not thoroughly tested.

minimum viable snippet

package main

import (
	"database/sql"
	"log"
	
	_ "gopkg.in/cq.v1"
)

func main() {
	db, err := sql.Open("neo4j-cypher", "http://localhost:7474")
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	stmt, err := db.Prepare(`
		match (n:User)-[:FOLLOWS]->(m:User) 
		where n.screenName = {0} 
		return m.screenName as friend
		limit 10
	`)
	if err != nil {
		log.Fatal(err)
	}
	defer stmt.Close()

	rows, err := stmt.Query("wefreema")
	if err != nil {
		log.Fatal(err)
	}
	defer rows.Close()

	var friend string
	for rows.Next() {
		err := rows.Scan(&friend)
		if err != nil {
			log.Fatal(err)
		}
		log.Println(friend)
	}
}

Neo4j version support

Neo4j feature support

deployment on Heroku w/ GrapheneDB

There is a repo with a template app for Heroku here. Use this Heroku deploy button to push the template project on to a new app on your Heroku account.

transactional API

The transactional API using db.Begin() is optimized for sending many queries to the transactional Cypher endpoint, in that it will batch them up and send them in chunks by default. Currently only supports stmt.Exec() within a transaction, will work on supporting stmt.Query() next and queueing up results.

transactional API example

func main() {
	db, err := sql.Open("neo4j-cypher", "http://localhost:7474")
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	tx, err := db.Begin()
	if err != nil {
		log.Fatal(err)
	}
	
	stmt, err := tx.Prepare("create (:User {screenName:{0}})")	
	if err != nil {
		log.Fatal(err)
	}
	
	stmt.Exec("wefreema")
	stmt.Exec("JnBrymn")
	stmt.Exec("technige")
	
	err := tx.Commit()
	if err != nil {
		log.Fatal(err)
	}
}

types subpackage

database/sql out of the box doesn't implement many types to pass in as parameters or Scan() out of rows. Custom Cypher types are implemented in the cq/types subpackage (import "gopkg.in/cq.v1/types"). These custom types allow users of cq to Scan() types out of results, as well as pass types in as parameters.

transactional API benchmarks

Able to get sustained times of 20k+ cypher statements per second, even with multiple nodes per create... on a 2011 vintage macbook.

(master ✓) wes-macbook:cq go test -bench=".*Transaction.*" -test.benchtime=10s
PASS
BenchmarkTransactional10SimpleCreate	  100000	    150630 ns/op
BenchmarkTransactional100SimpleCreate	  500000	     39202 ns/op
BenchmarkTransactional1000SimpleCreate	 1000000	     27320 ns/op
BenchmarkTransactional10000SimpleCreate	  500000	     28524 ns/op
ok  	github.com/wfreeman/cq	79.973s

thanks

Thanks to issue reporters and contributors!

license

MIT license. See license file.