Neo4jQuery

Tool that handles cypher syntax as method calls.

What is Neo4jQuery?

˙Neo4JQuery˙ is an implementation made to to use the query language 'Cypher' of the graph database ˙Neo4J˙ only.

#Why Neo4jQuery The library provides the strength of Cypher to use batch functionality like multiple matches and merges and creating relationships in one query.

It is also made to be more like programming a Cypher query than have lots of Cypher strings in the code which could be confusing.

Therefor you have lots of methods available in the query builder object which can be chained and is looking like a real cypher command in the end.

How to use

1. Download repository into a library folder (later it should be a npm module).
2. Install the module underscore via npm install underscore.
3. Install the driver module like seraph via npm install seraph.
4. Import both, seraph and Neo4jQuery, with 'require' and connect to your Neo4J graph database.

Quick example to get connection

var seraph = require("seraph")({
      server: "http://127.0.0.1:7474",
      endpoint: "/data/graph.db",
      user: "testuser",
      pass: "testpass"
      })
  , graph = require("neo4jquery").setConnection(seraph);

Documentation

Graph

Sets a driver which is connected to a Neo4J database. The only requirement is that the driver implements a method called 'query'.

Arguments

• connection (object) - A driver with a connection to a Neo4J database

Example

var graph = require("neo4jquery").setConnection(<driver object>);

Executes a passed-in query directly. Using parameters for parameterized cypher queries.

Arguments

• query (string) - The cypher query to be executed.
• parameters (object) - Parameters for parameterized queries.
• callback (function) - Callback function with parameters 'error' and 'array list'.

Example

var graph = require("neo4jquery").setConnection(<driver object>)
  , query = "MATCH (n:Node {field1: {v1}})-[r1:IS_LABEL]-(n2:Node2 {field2: {v2}}) RETURN n"
  , parameters = {v1: "value1", v2: "value2"}

  graph.Query(query, parameters, function(err, list) {
      if (err || void 0 === list) {
        callback(err, void 0);
      } else {
        // some stuff here with list
        var user = list[0];
      }
    });

Get the Cypher builder object.

Arguments

• No arguments

Example

var graph = require("neo4jquery").setConnection(<driver object>)
  , builder = graph.Builder();

Sets conditions to find specific nodes or relationships.

Arguments

• builder (Builder) - Cypher query builder object.
• cached (bool) - Flag to use the last cypher query.
• callback (function) - The callback function. Parameter of this function are first an error object and second an array as resultset.

Example

var graph = require("neo4jquery").setConnection(<driver object>)
  , builder = graph.Builder();

  builder
    .reset()
    .Match('n', 'User')
    .Where("n.username={username} and n.password={password}", {username: "testuser", password: "testpass"})

  graph.run(builder, false, function(err, list) {
    if (err || void 0 === list) {
      callback(err, void 0);
    } else {
      // some stuff here with list
      var user = list[0];
    }
  });

Executes the query and returns result set.

Arguments

• options (Object) - An config object with needed settings.

• builder (Builder) - The Cypher query builder you created the query with.
• cached (boolean) - Flag set to false for default. Set to true Neo4JQuery will use the last cached query for execution.
• aliases (Object) - Setting with aliases for the returned result placeholder
• success (function) - Callback function used if query was successful.
• error (function) - Callback function used if query was unsuccessful.

Example

var graph = require("neo4jquery").setConnection(<driver object>)
  , builder = graph.Builder();

    builder
      .reset()
      .Match('u', 'User', {username: "testuser", password: "testpass"});

    graph.execute({
      builder: builder,
      cached: false,
      aliases: {
        u: 'user'
      },
      success: function(results) {...},
      error: function(err) {...}
    });

Cypher Builder

Resets the builder object (inclusive cached query). Should be used to be as first method in the chain when you get the builder object.

Arguments

• No arguments

Example

var graph = require("neo4jquery").setConnection(<driver object>)
  , builder = graph.Builder();

  builder.reset();

Arguments

• placeholder (string) - The placeholder of the node or relationship.
• label (string) - The labels which are assigned to nodes.
• optional (boolean) - Flag to use 'OPTIONAL MATCH'. Default is false.
• parameters (object) - Parameters to filter nodes.

Example

var graph = require("neo4jquery").setConnection(<driver object>)
  , builder = graph.Builder();

  builder
    .reset()
    .Match('n', 'node', false, {field1: '...', field2: '...'});

  graph.execute({
    builder: builder,
    cached: false,
    aliases: {
      n: 'node'
    },
    success: function(results) {...},
    error: function(err) {...}
  });

Arguments

• placeholder (string) - The placeholder of the node or relationship.
• label (string) - The labels which are assigned to nodes.
• optional (boolean) - Flag to use 'OPTIONAL MATCH'. Default is false.
• parameters (object) - Parameters to filter nodes.

Example

var graph = require("neo4jquery").setConnection(<driver object>)
  , builder = graph.Builder();

  builder
    .reset()
    .OptionalMatch('n', 'node', {field1: '...', field2: '...'});

  graph.execute({
    builder: builder,
    cached: false,
    aliases: {
      n: 'node'
    },
    success: function(results) {...},
    error: function(err) {...}
  });

Arguments

• placeholder (string) - The placeholder of the node.
• label (string) - The labels which are assigned to the node.
• parameters (object) - Parameters of the node.

Example

var graph = require("neo4jquery").setConnection(<driver object>)
  , builder = graph.Builder();

  builder
    .reset()
    .Merge('u', 'User', {field1: '...', field2: '...', createdAt: 120987654321});

  graph.execute({
    builder: builder,
    cached: false,
    aliases: {
      u: 'user'
    },
    success: function(results) {...},
    error: function(err) {...}
  });

Arguments

• nodes (array) - The placeholder of the nodes which has to be connected with each other.
• placeholder (string) - The placeholder of the relationship.
• label (string) - The labels which are assigned to the relationship.
• parameters (object) - Parameters of the relationship.

Example

// Here the first value in the nodes array points to the second value 
// via relationship 'ASSIGNED_WITH_EACH_OTHER'!
var graph = require("neo4jquery").setConnection(<driver object>)
  , builder = graph.Builder();

  builder
    .reset()
    .Match('u', 'User', false, {field1: ..., field2: ...})
    .With(['u'])
    .Merge('n', 'Node', false, {field1: '...', field2: '...', createdAt: 120987654321})
    .With(['u', 'n'])
    .MergeRelationShip(['n', 'u'], 'r', 'ASSIGNED_WITH_EACH_OTHER', {field1: '...', field2: '...'});

  graph.execute({
    builder: builder,
    cached: false,
    aliases: {
      u: 'user',
      n: 'node',
      r: 'relation'
    },
    success: function(results) {...},
    error: function(err) {...}
  });

Arguments

• command (string) - The command like SET followed by what to do.

Example

var graph = require("neo4jquery").setConnection(<driver object>)
  , builder = graph.Builder();

  builder
    .reset()
    .Merge('u', 'User', {field1: ..., field2: ...})
    .relate('r1', 'GUESSED_RELATIONSHIP')
    .toNode('n', 'Note', {field3: ..., field4: ...})
    .onCreate('SET u.createdAt=timestamp(), n.createdAt=timestamp()');

  graph.execute({
    builder: builder,
    cached: false,
    aliases: {
      u: 'user',
      n: 'node'
    },
    success: function(results) {...},
    error: function(err) {...}
  });

Arguments

• command (string) - The command like SET followed by what to do.

Example

var graph = require("neo4jquery").setConnection(<driver object>)
  , builder = graph.Builder();

  builder
    .reset()
    .Merge('u', 'User', {field1: ..., field2: ...})
    .relate('r1', 'GUESSED_RELATIONSHIP')
    .toNode('n', 'Note', {field3: ..., field4: ...})
    .onMatch('SET u.visited=timestamp(), n.visited=timestamp()');

  graph.execute({
    builder: builder,
    cached: false,
    aliases: {
      u: 'user',
      n: 'node'
    },
    success: function(results) {...},
    error: function(err) {...}
  });

Arguments

• placeholder (string|array) - The placeholder of node/nodes to be deleted.

Example

var graph = require("neo4jquery").setConnection(<driver object>)
  , builder = graph.Builder();

  builder
    .reset()
    .Match('u', 'User', {...})
    .relate('r1', 'RELATIONSHIP', {...})
    .toNode('u2', 'User', {...})
    .Delete(['r1', 'u', 'u2']);

  graph.execute({
    builder: builder,
    success: function(results) {...},
    error: function(err) {...}
  });

Arguments

• placeholders (array) - An array with all placeholders which have to be connected with next cypher command.

Example

var graph = require("neo4jquery").setConnection(<driver object>)
  , builder = graph.Builder();

  builder
    .reset()
    .Match('u', 'User', {username: 'neo4jqueryuser', password: 'password'})
    .With(['u'])
    .MergeRelationShip(['u'], 'r', 'ASSIGNED_WITH_EACH_OTHER', {field1: '...', field2: '...'});

  graph.execute({
    builder: builder,
    cached: false,
    aliases: {
      u: 'user',
      r: 'relation'
    },
    success: function(results) {...},
    error: function(err) {...}
  });

Sets conditions to find specific nodes or relationships.

Arguments

• string (string) - The conditions to filter nodes and/or relationships.
• parameter (object) - The parameters for prepared cypher statements provided by the NodeJS driver.

Example

var graph = require("neo4jquery").setConnection(<driver object>)
  , builder = graph.Builder();

  builder
    .reset()
    .Match('u', 'User')
    .Where("u.username={username} and u.password={password}", {username: 'testuser', password: 'password'});

  graph.execute({
    builder: builder,
    cached: false,
    aliases: {
      u: 'user'
    },
    success: function(results) {...},
    error: function(err) {...}
  });

Sets given properties to a node or relationship.

Arguments

• placeholder (string) - The placeholder of the node or relationship.
• parameter (object) - All parameters to be set as properties in the node or relationship.

Example

var graph = require("neo4jquery").setConnection(<driver object>)
  , builder = graph.Builder();

  builder
    .reset()
    .Match('u', 'User')
    .Where("u.username={username} and u.password={password}", {username: 'testuser', password: 'password'})
    .Set('u', {createdAt: 1440360134452, updatedAt: 1440360134452});

  graph.execute({
    builder: builder,
    cached: false,
    aliases: {
      u: 'user'
    },
    success: function(results) {...},
    error: function(err) {...}
  });

Adds a cypher foreach loop to the query to update the nodes in a list.

Arguments

• condition (string) - The condition to iterate over a list of nodes.
• query (string) - The update command.

Example

var graph = require("neo4jquery").setConnection(<driver object>)
  , builder = graph.Builder();

  builder
    .reset()
    .Match('u', 'User')
    .Where("u.updatedAt > {timestamp}", {timestamp: new Date().getTime() - 3600})
    .ForeachCondition('user IN u', 'SET u.visited=true');

  graph.execute({
    builder: builder,
    cached: false,
    aliases: {
      u: 'user'
    },
    success: function(results) {...},
    error: function(err) {...}
  });