Seraph.js
A terse & familiar binding to the Neo4j REST API that is idiomatic to node.js.
Install
npm install seraph
Quick Example
var db = require("seraph")("http://localhost:7474");
db.save({ name: "Test-Man", age: 40 }, function(err, node) {
if (err) throw err;
console.log("Test-Man inserted.");
db.delete(node, function(err) {
if (err) throw err;
console.log("Test-Man away!");
});
});
Documentation
Initialization
- seraph - initialize the seraph client
- changePassword - change the db user's password
Generic Operations
- query - perform a cypher query and parse the results
- queryRaw - perform a cypher query and return unparsed results
API Communication Operations
- operation - create a representation of a REST API call
- call - take an operation and call it
- batch - perform a series of atomic operations with one api call.
Node Operations
- save (node.save) - create or update a node
- read (node.read) - read a node
- find (node.find) - find a node using a predicate
- delete (node.delete) - delete a node
- relate (node.relate) - relate two nodes
- relationships (node.relationships) - read the relationships of a node
- legacyindex (node.legacyindex) - add a node to a legacy index
- label (node.label) - add a label to a node
- removeLabel (node.removeLabel) - remove a label from a node
- nodesWithLabel (node.nodesWithLabel) - fetch all nodes with a label
- readLabels (node.readLabels) - read the labels of a node or all available labels.
Relationship Operations
- rel.create - create a relationship
- rel.update - update the properties of a relationship
- rel.read - read a relationship
- rel.delete - delete a relationship
Constraint operations
- constraints.list - list constraints
- constraints.uniqueness.create - create a uniqueness constraint
- constraints.uniqueness.createIfNone - create a uniqueness constraint if it doesn't already exist
- constraints.uniqueness.list - list uniqueness constraints
- constraints.uniqueness.drop - drop a uniqueness constraint
Indexing operations
- index.create - create an index on a label and property name
- index.createIfNone - create an index or return the old one
- index.list - read out the indexes for a label
- index.drop - drop an index
Legacy Index Operations
- legacyindex.create - create an index
- legacyindex.add - add a nodes/rels to an index
- legacyindex.read - read nodes/rels from an index
- legacyindex.remove - remove nodes/rels from an index
- legacyindex.delete - delete an index
- legacyindex.getOrSaveUnique - get or save a node using an index for uniqueness
- legacyindex.saveUniqueOrFail - save a node using an index to enforce uniqueness
Compatibility
Seraph ~0.15
has been tested with with Neo4j 3.
Testing
You can test Seraph simply by running npm test
. It will spin up its own neo4j
instance for testing. Note that the first time you run your tests (or change
neo4j version), a new version of neo4j will need to be downloaded. That can,
of course, take a little time.
Initialization
seraph([server|options])
Creates and returns the Seraph instance. If no parameters are given,
assumes the Neo4J REST API is running locally at the default location
http://localhost:7474/db/data
.
Arguments
options
: an options object. You can use the following options:server
(default ="http://localhost:7474"
): the server to connect to (with protocol and port, not path).endpoint
(default ="/db/data"
): the path to Neo4j's rest API. You can leave this as the default if you have not changed it yourself in the neo4j settings.user
(default ="neo4j"
): the username to authenticate with.pass
(default ="neo4j"
): the password to authenticate with.id
(default ="id"
): the name of the attribute seraph will add to new nodes when they are created and that it will use to find nodes when performing updates withnode.save
and the like.agent
(default = null): the http agent for requests to neo4j server. The same can be used for keep-alive connections to server. Can use agentkeepalive module to create a keep-alive agent. It's a recommended option for high performance and low latency client.xstream
(default = false): if true, passes new X-Stream option to neo4j server. It's a recommended option for high performance and low latency client.
server
(string) - Short form to specify server parameter only."http://localhost:4747"
is equivalent to{ server: "http://localhost:4747" }
.
Note that as of Neo4j 2.2.0, user authentication is required. You will not
be able to access resources before supplying a username or password that is not
the default. You can change the password using seraph#changePassword
.
Example
// To http://localhost:7474/db/data with user "local" and pass "test"
var dbLocal = require("seraph")({
user: 'local',
pass: 'test'
});
// To http://example.com:53280/neo with user "root" and pass "jf8%kLs#!"
var dbRemote = require("seraph")({ server: "http://example.com:53280",
endpoint: "/neo",
user: "root",
pass: "jf8%kLs#!" });
// Copy node#13 from remote server
dbRemote.read({ id: 13 }, function(err, node) {
if (err) throw err;
delete node.id; // copy instead of overwriting local node#13
dbLocal.save(node, function(err, nodeL) {
if (err) throw err;
console.log("Copied remote node#13 to " +
"local node#" + nodeL.id.toString() + ".");
});
});
changePassword(newPassword, callback)
Change's the current database user's password. This will automatically update seraph's options to contain the new password if it is successful
Arguments
newPassword
(string) - the new password to set.callback
(function(err){}) - callback to call when the password has been changed.
Example
// connect to a local neo4j instance with default settings (user/pass is "neo4j" by default).
var db = require("seraph")();
db.changePassword('b2(jk:4@#', function(err) {
//password is now changed, and `db`'s options have been updated with the new password
});
Generic Operations
query(query, [params,] callback), queryRaw(query, [params,] callback)
queryRaw
performs a cypher query and returns the results directly from the
REST API.
query
performs a cypher query and map the columns and results together.
Note: if you're performing large queries it may be advantageous to use
queryRaw
, since query
attempts to infer whole nodes and relationships that
are returned (in order to transform them into a nicer format).
Arguments
query
- Cypher query as a format string.params
(optional, default={}
). Replace{key}
parts in query string. See cypher documentation for details. note that if you want to send a list of ids as a parameter, you should send them as an array, rather than a string representing them ([2,3]
rather than"2,3"
).callback
- (err, result). Result is an array of objects.
Example
Given database:
{ name: 'Jon', age: 23, id: 1 }
{ name: 'Neil', age: 60, id: 2 }
{ name: 'Katie', age: 29, id: 3 }
// 1 --knows--> 2
// 1 --knows--> 3
Return all people Jon knows:
var cypher = "START x = node({id}) "
+ "MATCH x -[r]-> n "
+ "RETURN n "
+ "ORDER BY n.name";
db.query(cypher, {id: 1}, function(err, result) {
if (err) throw err;
assert.deepEqual(result, [
{ name: 'Katie', age: 29, id: 3 },
{ name: 'Neil', age: 60, id: 2 }
]);
};
db.queryRaw(cypher, {id: 3}, function(err, result) {
if (err) throw err;
// result contains the raw response from neo4j's rest API. See
// http://docs.neo4j.org/chunked/milestone/rest-api-cypher.html
// for more info
});
operation(path, [method='get/post'], [data])
Create an operation object that will be passed to call.
Arguments
path
- the path fragment of the request URL with no leading slash.method
(optional, default='GET'
|'POST'
) - the HTTP method to use. Whendata
is an object,method
defaults to 'POST'. Otherwise,method
defaults toGET
.data
(optional) - an object to send to the server with the request.
Example
var operation = db.operation('node/4285/properties', 'PUT', { name: 'Jon' });
db.call(operation, function(err) {
if (!err) console.log('Set `name` to `Jon` on node 4285!');
});
call(operation, callback)
Perform an HTTP request to the server.
If the body is some JSON, it is parsed and passed to the callback.If the status code is not in the 200's, an error is passed to the callback.
Arguments
operation
- an operation created by operation that specifies what to request from the servercallback
- function(err, result, response).result
is the JSON parsed body from the server (otherwise empty).response
is the response object from the request.
Example
var operation = db.operation('node/4285/properties');
db.call(operation, function(err, properties) {
if (err) throw err;
// `properties` is an object containing the properties from node 4285
});
Batching/transactions - batch([operations, callback])
Batching provides a method of performing a series of operations atomically. You could also call it a transaction. It has the added benefit of being performed all in a single call to the neo4j api, which theoretically should result in improved performance when performing more than one operation at the same time.
When you create a batch, you're given a new seraph
object to use. All calls to
this object will be added to the batch. Note that once a batch is committed, you
should no longer use this object.
- How do I use it?
- What happens to my callbacks?
- Can I reference newly created nodes?
- I didn't use any callbacks. How can I find my results when the batch is done?
- What happens if one of the operations fails?
- Can I nest batches?
- How can I tell if this
db
object is a batch operation?
How do I use it?
There's two ways. You can do the whole thing asynchronously, and commit the transaction whenever you want, or you can do it synchronously, and have the transaction committed for you as soon as your function is finished running. Here's a couple of examples of performing the same operations with batch synchronously and asynchronously:
Asynchronously
var txn = db.batch();
txn.save({ title: 'Kaikki Askeleet' });
txn.save({ title: 'SinΓ€ Nukut SiinΓ€' });
txn.save({ title: 'Pohjanmaa' });
txn.commit(function(err, results) {
/* results -> [{ id: 1, title: 'Kaikki Askeleet' },
{ id: 2, title: 'SinΓ€ Nukut SiinΓ€' },
{ id: 3, title: 'Pohjanmaa' }] */
});
Synchronously
Note - it's only the creation of operations that is synchronous. The actual API call is asynchronous still, of course.
db.batch(function(txn) {
txn.save({ title: 'Kaikki Askeleet' });
txn.save({ title: 'SinΓ€ Nukut SiinΓ€' });
txn.save({ title: 'Pohjanmaa' });
}, function(err, results) {
/* results -> [{ id: 1, title: 'Kaikki Askeleet' },
{ id: 2, title: 'SinΓ€ Nukut SiinΓ€' },
{ id: 3, title: 'Pohjanmaa' }] */
});
What happens to my callbacks?
You can still pass callbacks to operations on a batch transaction. They will perform as you expect, but they will not be called until after the batch has been committed. Here's an example of using callbacks as normal:
var txn = db.batch();
txn.save({ title: 'Marmoritaivas' }, function(err, node) {
// this code is not reached until `txn.commit` is called
// node -> { id: 1, title: 'Marmoritaivas' }
});
txn.commit();
Can I reference newly created nodes?
Yes! Calling, for example, node.save
will synchronously return a special object
which you can use to refer to that newly created node within the batch.
For example, this is perfectly valid in the context of a batch transaction:
var txn = db.batch();
var singer = txn.save({name: 'Johanna Kurkela'});
var album = txn.save({title: 'KauriinsilmΓ€t', year: 2008});
var performance = txn.relate(singer, 'performs_on', album, {role: 'Primary Artist'});
txn.rel.legacyindex('performances', performance, 'year', '2008');
txn.commit(function(err, results) {});
I didn't use any callbacks. How can I find my results when the batch is done?
Each function you call on the batch object will return a special object that you can use to refer to that call's results once that batch is finished (in addition to the intra-batch referencing feature mentioned above). The best way to demonstrate this is by example:
var txn = db.batch();
var album = txn.save({title: 'Hetki Hiljaa'});
var songs = txn.save([
{ title: 'Olen Sinussa', length: 248 },
{ title: 'Juurrun TÀhÀn IkÀvÀÀn', length: 271 }
]);
// note we can also use `songs` to reference the node that will be created
txn.relate(album, 'has_song', songs[0], { trackNumber: 1 });
txn.relate(album, 'has_song', songs[1], { trackNumber: 3 });
txn.commit(function(err, results) {
var album = results[album]; // album -> { title: 'Hetki Hiljaa', id: 1 }
var tracks = results[songs];
/* tracks -> [{ title: 'Olen Sinussa', length: 248, id: 2 },
{ title: 'Juurrun TÀhÀn IkÀvÀÀn', length: 271, id: 3}] */
});
What happens if one of the operations fails?
Then no changes are made. Neo4j's batch transactions are atomic, so if one operation fails, then no changes to the database are made. Neo4j's own documentation has the following to say:
This service is transactional. If any of the operations performed fails (returns a non-2xx HTTP status code), the transaction will be rolled back and all changes will be undone.
Can I nest batches?
No, as of now we don't support nesting batches as it tends to confuse the
intra-batch referencing functionality. To enforce this, you'll find that the
seraph-like object returned by db.batch()
has no .batch
function itself.
db
object is a batch operation?
How can I tell if this Like so:
// db.isBatch -> undefined
var txn = db.batch();
// txn.isBatch -> true
if (txn.isBatch) // Woo! I'm in a batch.
Node Operations
save(object, [label,]|[key, value,] callback)
Aliases: node.save
Create or update a node. If object
has an id property, the node with that id
is updated. Otherwise, a new node is created. Returns the newly created/updated
node to the callback.
** Note: using node.save
with a label
does not work in a batch. If you
want to create a node with label in a batch, you should call node.save
without
a label, followed by node.label
with a reference to the created node. **
Arguments
node
- an object to create or updatelabel
- a label to label this node with. this is performed atomically, so if labelling the node fails, the node is not saved/updated. supplyinglabel
is exclusive withkey
andvalue
. You may either specify alabel
, or akey
and avalue
, but all three. ** Note: usingnode.save
with alabel
does not work in a batch. If you want to create a node with label in a batch, you should callnode.save
without a label, followed bynode.label
with a reference to the created node. **key
,value
(optional) - a property key and a value to update it with. This allows you to only update a single property of the node, without touching any others. Ifkey
is specified,value
must also be.callback
- function(err, node).node
is the newly saved or updated node. If a create was performed,node
will now have an id property. The returned object is not the same reference as the passed object (the passed object will never be altered).
Example
** Creating and updating a node **
// Create a node
db.save({ name: 'Jon', age: 22, likes: 'Beer' }, function(err, node) {
console.log(node); // -> { name: 'Jon', age: 22, likes: 'Beer', id: 1 }
// Update it
delete node.likes;
node.age++;
db.save(node, function(err, node) {
console.log(node); // -> { name: 'Jon', age: 23, id: 1 }
});
});
** Creating a node with a label **
db.save({ name: 'Jon' }, 'Person', function(err, node) {
});
** Update a single property on a node **
db.save({ name: 'Jon', age: 23 }, 'Person', function(err, node) {
db.save(node, 'age', 24, function(err) {
});
});
read(id|object, [property,] callback)
Aliases: node.read
Read a node.
Note: If the node doesn't exist, Neo4j will return an exception. You can
check if this is indicating that your node doesn't exist because
err.statusCode
will equal 404
. This is inconsistent with behaviour of
node.legacyindex.read, but it is justified because the
Neo4j REST api behaviour is inconsistent in this way as well.
Arguments
id | object
- either the id of the node to read, or an object containing an id property of the node to read.property
(optional) - the name of the property to read. if this is specified, only the value of this property on the object is returned.callback
- function(err, node).node
is an object containing the properties of the node with the given id.
Example
db.save({ make: 'Citroen', model: 'DS4' }, function(err, node) {
db.read(node.id, function(err, node) {
console.log(node) // -> { make: 'Citroen', model: 'DS4', id: 1 }
});
});
delete(id|object, [force | property], [callback])
Aliases: node.delete
Delete a node.
Arguments
id | object
- either the id of the node to delete, or an object containing an id property of the node to delete.force
(optional - default = false) - if truthy, will delete all the node's relations prior to deleting the node.property
(optional) - if specified, delete only the property with this name on the object. note that you can either specifyproperty
orforce
, not both, as force is meaningless when deleting a propertycallback
- function(err). iferr
is falsy, the node has been deleted.
Example
db.save({ name: 'Jon' }, function(err, node) {
db.delete(node, function(err) {
if (!err) console.log('Jon has been deleted!');
});
});
find(predicate, [any, [label,] callback)
Aliases: node.find
Perform a query based on a predicate. The predicate is translated to a cypher query.
Arguments
predicate
- Partially defined object. Will return elements which match the defined attributes of predicate.any
(optional, default=false
) - If true, elements need only match on one attribute. If false, elements must match on all attributes.label
(optional, default=null
) - Find only nodes with the given label. (neo4j docs on labels)callback
- function(err, results) -results
is an array of the resulting nodes.
Example
Given database content:
{ name: 'Jon' , age: 23, australian: true }
{ name: 'Neil' , age: 60, australian: true }
{ name: 'Belinda', age: 26, australian: false }
{ name: 'Katie' , age: 29, australian: true }
Retrieve all australians:
var predicate = { australian: true };
var people = db.find(predicate, function (err, people) {
if (err) throw err;
assert.equals(3, people.length);
});
relationships(id|object, [direction, [type,]] callback)
*Aliases: node.relationships
Read the relationships involving the specified node.
Arguments
id | object
- either the id of a node, or an object containing an id property of a node.direction
('all'|'in'|'out') (optional unlesstype
is passed, default='all'
) - the direction of relationships to read.type
(optional, default=''
(match all relationships)) - the relationship type to findcallback
- function(err, relationships) -relationships
is an array of the matching relationships
Example
db.relationships(452, 'out', 'knows', function(err, relationships) {
// relationships = all outgoing `knows` relationships from node 452
});
label(id|object(s), label(s), [replace,] callback)
Aliases: node.label
Add a label to a node.
Arguments
id|object(s)
- either the id of the node to label, or an object containing an id property of the node to label. can be an array of objects/ids.label(s)
- the label(s) to apply. can be an array of labels.replace
(optional) - if set to true, this label will replace any previous labels.callback
- function(err). if err is falsy, the operation succeeded.
Example
db.save({ make: 'Citroen', model: 'DS4' }, function(err, node) {
db.label(node, ['Car', 'Hatchback'], function(err) {
// `node` is now labelled with "Car" and "Hatchback"!
});
});
removeLabel(id|object(s), label, callback)
Aliases: node.removeLabel
Remove a label from a node.
Arguments
id|object(s)
- either the id of the node to delabel, or an object containing an id property of the node to delabel. can be an array of objects/ids.label
- the label to remove. cannot be an array.callback
- function(err). if err is falsy, the operation succeeded.
Example
db.save({ make: 'Citroen', model: 'DS4' }, function(err, node) {
db.label(node, ['Car', 'Hatchback'], function(err) {
// `node` is now labelled with "Car" and "Hatchback"!
db.removeLabel(node, 'Hatchback', function(err) {
// `node` is now only labelled with "Car".
});
});
});
nodesWithLabel(label, callback)
Aliases: node.nodesWithLabel
Fetch all of the nodes that are labelled with a specific label.
Arguments
label
- the label.callback
- function(err, results). results is always an array (assuming no error), containing the nodes that were labelled withlabel
. if no nodes were labelled withlabel
,results
is an empty array.
Example
db.save({ make: 'Citroen', model: 'DS4' }, function(err, node) {
db.label(node, ['Car', 'Hatchback'], function(err) {
db.nodesWithLabel('Car', function(err, results) {
results[0].model // -> 'DS4'
});
});
});
readLabels([node(s),] callback)
Aliases: node.readLabels
Read the labels of a node, or all labels in the database.
Arguments
node(s)
(optional) - the node to return the labels of. if not specified, every label in the database is returned. can be an array of nodes.callback
- function(err, labels). labels is an array of labels.
Example
db.save({ make: 'Citroen', model: 'DS4' }, function(err, node) {
db.label(node, ['Car', 'Hatchback'], function(err) {
db.readLabels(node, function(err, labels) {
//labels -> ['Car', 'Hatchback']
});
});
});
Relationship Operations
rel.create(firstId|firstObj, type, secondId|secondobj, [properties], callback)
Aliases: relate, node.relate
Create a relationship between two nodes.
Arguments
firstId | firstObject
- id of the start node or an object with an id property for the start nodetype
- the name of the relationshipsecondId | secondObject
- id of the end node or an object with an id property for the end nodeproperties
(optional, default={}
) - properties of the relationshipcallback
- function(err, relationship) -relationship
is the newly created relationship
Example
db.relate(1, 'knows', 2, { for: '2 months' }, function(err, relationship) {
assert.deepEqual(relationship, {
start: 1,
end: 2,
type: 'knows',
properties: { for: '2 months' },
id: 1
});
});
rel.update(relationship, [key, value,] callback)
Update the properties of a relationship. Note that you cannot use this method to update the base properties of the relationship (start, end, type) - in order to do that you'll need to delete the old relationship and create a new one.
Arguments
relationship
- the relationship object with some changed propertieskey
,value
(optional) - if a key and value is specified, only the property with that key will be updated. the rest of the object will not be touched.callback
- function(err). if err is falsy, the update succeeded.
Example
var props = { for: '2 months', location: 'Bergen' };
db.rel.create(1, 'knows', 2, props, function(err, relationship) {
delete relationship.properties.location;
relationship.properties.for = '3 months';
db.rel.update(relationship, function(err) {
// properties on this relationship in the database are now equal to
// { for: '3 months' }
});
});
rel.read(object|id, callback)
Read a relationship.
Arguments
object | id
- the id of the relationship to read or an object with an id property of the relationship to read.callback
- function(err, relationship).relationship
is an object representing the read relationship.
Example
db.rel.create(1, 'knows', 2, { for: '2 months' }, function(err, newRelationship) {
db.rel.read(newRelationship.id, function(err, readRelationship) {
assert.deepEqual(newRelationship, readRelationship);
assert.deepEqual(readRelationship, {
start: 1,
end: 2,
type: 'knows',
id: 1,
properties: { for: '2 months' }
});
});
});
rel.delete(object|id, [callback])
Delete a relationship.
Arguments
object | id
- the id of the relationship to delete or an object with an id property of the relationship to delete.callback
- function(err). Iferr
is falsy, the relationship has been deleted.
Example
db.rel.create(1, 'knows', 2, { for: '2 months' }, function(err, rel) {
db.rel.delete(rel.id, function(err) {
if (!err) console.log("Relationship was deleted");
});
});
Constraints Operations
constraints.list([label,] callback)
List all constraints, or optionally all constraints for a label.
Arguments
label
(optional) - the label to list constraints forcallback
- function(err, constraints).constraints
is an array of constraint objects. For example,[{type:'UNIQUENESS', label:'Person', property_keys['name']}]
Example
db.constraints.list('Person', function(err, constraints) {
console.log(constraints);
// -> [{ type: 'UNIQUENESS', label: 'Person', property_keys: ['name'] }]
});
constraints.uniqueness.list(label, [key,] callback)
List all uniqueness constraints, or optionally fetch a uniqueness constraint for
key
.
Arguments
label
- the label to list uniqueness constraints forkey
(optional) - if specified, retrieve any uniqueness constraint for this property key.callback
- function(err, constraints).constraints
is an array of constraint objects. For example,[{type:'UNIQUENESS', label:'Person', property_keys: ['name']}]
. If none existed, it is an empty array.
Example
db.constraints.uniqueness.list('Person', 'name', function(err, constraints) {
console.log(constraints);
// -> [{ type: 'UNIQUENESS', label: 'Person', property_keys: ['name'] }]
});
constraints.uniqueness.create(label, key, callback)
Create a uniqueness constraint on the given label. Any node labelled with label
will be constrained to having a unique value for the given key
. If it doesn't,
attempting to label that node with label
will return an error (unfortunately
due to the way neo4j handles these errors, the statusCode is 400 instead of 409,
but you can check with
err.neo4jCause.exception == 'ConstraintViolationException'
.
Arguments
label
- the label to create a uniqueness constraint forkey
- the key that should be unique on nodes labelled withlabel
callback
- function(err, constraint).constraint
is a constraint object representing the constraint that was created, e.g.[{type:'UNIQUENESS', label:'Person', property_keys['name']}]
. If the constraint already existed,err.statusCode == 409
.
Example
// any node labelled Person should have a unique `name`
db.constraints.uniqueness.create('Person', 'name', function(err, constraint) {
console.log(constraint);
// -> { type: 'UNIQUENESS', label: 'Person', property_keys: ['name'] }
});
constraints.uniqueness.createIfNone(label, key, callback)
Create a uniqueness constraint on the given label. If the constraint exists, don't return an error, just return the existing constraint.
Arguments
label
- the label to create a uniqueness constraint forkey
- the key that should be unique on nodes labelled withlabel
callback
- function(err, constraint).constraint
is a constraint object representing the constraint that was created, e.g.[{type:'UNIQUENESS', label:'Person', property_keys: ['name']}]
.
Example
// any node labelled Person should have a unique `name`
db.constraints.uniqueness.createIfNone('Person', 'name', function(err, constraint) {
console.log(constraint);
// -> { type: 'UNIQUENESS', label: 'Person', property_keys: ['name'] }
db.constraints.uniqueness.createIfNone('Person', 'name', function(err, constraint) {
console.log(err);
// -> undefined
console.log(constraint);
// -> { type: 'UNIQUENESS', label: 'Person', property_keys: ['name'] }
});
});
constraints.uniqueness.drop(label, key, callback)
Drop (remove) a uniqueness constraint.
Arguments
label
- the label to remove a uniqueness constraint fromkey
- the key on which to remove the uniqueness constraintcallback
- function(err). iferr
is falsy, the constraint was successfully dropped
Example
// any node labelled Person should have a unique `name`
db.constraints.uniqueness.create('Person', 'name', function(err, constraint) {
console.log(constraint);
// -> { type: 'UNIQUENESS', label: 'Person', property_keys: ['name'] }
db.constraints.uniqueness.drop('Person', 'name', function(err) {
console.log(err);
// -> undefined
// the constraint has been dropped
});
});
Indexing Operations
For more of an overview on schema-based indexing, check out the neo4j docs on the subject.
index.create(label, key, callback)
Create an index on label
with key
. Note that schema-based indexes are
performance-boosting only and do not imply any uniqueness constraints.
Arguments
label
- the label to create an index onkey
- the key to index, i.e.'name'
. Note that compound indexes are not yet supported by neo4j-2callback
- function(err, index).index
is an object that reflects the index that was created, i.e.{ label: 'Person', property_keys: ['name'] }
. Note that if you've already created the index, you'll get a conflict error. You can check this by checkingerr
'sstatusCode
property.409
indicates a conflict. You can avoid this by using index.createIfNone
Example
db.index.create('Person', 'name', function(err, index) {
console.log(index); // -> { label: 'Person', property_keys: ['name'] }
});
index.createIfNone(label, key, callback)
Create an index on label
with key
. Exactly the same as
index.create except it will not throw an error if it encounters
a conflict.
Arguments
label
- the label to create an index onkey
- the key to index, i.e.'name'
. Note that compound indexes are not yet supported by neo4j-2callback
- function(err, index).index
is an object that reflects the index that was created, i.e.{ label: 'Person', property_keys: ['name'] }
.
Example
db.index.createIfNone('Person', 'name', function(err, index) {
console.log(index); // -> { label: 'Person', property_keys: ['name'] }
});
index.list(label, callback)
Retrieve a listing of the indexes on a label.
Arguments
label
- the label to retrieve indexes forcallback
- function(err, indexes).indexes
is an array of objects that reflect the indexes on this label, i.e.[{ label: 'Person', property_keys: ['name'] }]
.
Example
db.index.list('Person', function(err, index) {
console.log(index); // -> [ { label: 'Person', property_keys: ['name'] } ]
});
index.drop(label, key, callback)
Drop an index from a label
Arguments
label
- the label to drop the index fromkey
- the key to drop the index fromcallback
- function(err). iferr
is falsy, the index was dropped successfully.
Example
db.index.drop('Person', 'name' function(err) {
if (!err) console.log('Index dropped!');
});
Legacy Index Operations
Note that as of Neo4j-2.0.0 legacy indexes are no longer the preferred way to handle indexing
node.legacyindex.create(name, [config,] callback)
rel.legacyindex.create(name, [config,] callback)
Create a new legacy index. If you're using the default legacy index configuration, this method is not necessary - you can just start using the legacy index with legacyindex.add as if it already existed.
NOTE for legacy index functions: there are two different types of legacy
index in neo4j - node legacy indexes and relationship legacy indexes.
When you're working with node legacy indexes, you use the functions on
node.legacyindex
. Similarly, when you're working on relationship legacy
indexes you use the functions on rel.legacyindex
. Most of the functions on
both of these are identical (excluding the uniqueness functions), but one acts
upon node legacy indexes, and the other upon relationship legacy indexes.
Arguments
name
- the name of the legacy index that is being createdconfig
(optional, default={}
) - the configuration of the legacy index. See the neo4j docs for more information.callback
- function(err). Iferr
is falsy, the legacy index has been created.
Example
var indexConfig = { type: 'fulltext', provider: 'lucene' };
db.node.legacyindex.create('a_fulltext_index', indexConfig, function(err) {
if (!err) console.log('a fulltext legacy index has been created!');
});
node.legacyindex.add(indexName, id|object, key, value, callback);
rel.legacyindex.add(indexName, id|object, key, value, callback);
node.legacyindex.add
is aliased as node.legacyindex & legacyindex
Add a node/relationship to a legacy index.
NOTE for legacy index functions: there are two different types of legacy
index in neo4j - node legacy indexes and relationship legacy indexes.
When you're working with node legacy indexes, you use the functions on
node.legacyindex
. Similarly, when you're working on relationship legacy
indexes you use the functions on rel.legacyindex
. Most of the functions on
both of these are identical (excluding the uniqueness functions), but one acts
upon node legacy indexes, and the other upon relationship legacy indexes.
Arguments
indexName
- the name of the legacy index to add the node/relationship to.id | object
- the id of the node/relationship to add to the legacy index or an object with an id property of the node/relationship to add to the legacy index.key
- the key to index the node/relationship withvalue
- the value to index the node/relationship withcallback
- function(err). Iferr
is falsy, the node/relationship has been indexed.
Example
db.save({ name: 'Jon' }, function(err, node) {
db.legacyindex('people', node, 'name', node.name, function(err) {
if (!err) console.log('Jon has been indexed!');
});
});
node.legacyindex.read(indexName, key, value, callback);
rel.legacyindex.read(indexName, key, value, callback);
Read the object(s) from a legacy index that match a key-value pair. See also legacyindex.readAsList.
NOTE for legacy index functions: there are two different types of legacy
index in neo4j - node legacy indexes and relationship legacy indexes.
When you're working with node legacy indexes, you use the functions on
node.legacyindex
. Similarly, when you're working on relationship legacy
indexes you use the functions on rel.legacyindex
. Most of the functions on
both of these are identical (excluding the uniqueness functions), but one acts
upon node legacy indexes, and the other upon relationship legacy indexes.
Arguments
indexName
- the legacy index to read fromkey
- the key to matchvalue
- the value to matchcallback
- function(err, results).results
is a node or relationship object (or an array of them if there was more than one) that matched the given key-value pair in the given legacy index. If nothing matched,results === false
. legacyindex.readAsList is similar, but always givesresults
as an array, with zero, one or more elements.
Example
db.rel.legacyindex.read('friendships', 'location', 'Norway', function(err, rels) {
// `rels` is an array of all relationships indexed in the `friendships`
// index, with a value `Norway` for the key `location`.
});
node.legacyindex.readAsList(indexName, key, value, callback);
rel.legacyindex.readAsList(indexName, key, value, callback);
Read the object(s) from a legacy index that match a key-value pair. See also legacyindex.read.
NOTE for legacy index functions: there are two different types of legacy
index in neo4j - node legacy indexes and relationship legacy indexes.
When you're working with node legacy indexes, you use the functions on
node.legacyindex
. Similarly, when you're working on relationship legacy
indexes you use the functions on rel.legacyindex
. Most of the functions on
both of these are identical (excluding the uniqueness functions), but one acts
upon node legacy indexes, and the other upon relationship legacy indexes.
Arguments
indexName
- the legacy index to read fromkey
- the key to matchvalue
- the value to matchcallback
- function(err, results).results
is an array of node or relationship objects that matched the given key-value pair in the given legacy index. legacyindex.read is similar, but givesresults
asfalse
, an object or an array of objects depending on the number of hits.
Example
db.rel.legacyindex.readAsList('friendships', 'location', 'Norway', function(err, rels) {
// `rels` is an array of all relationships indexed in the `friendships`
// legacy index, with a value `Norway` for the key `location`.
});
node.legacyindex.remove(indexName, id|object, [key, [value,]] callback);
rel.legacyindex.remove(indexName, id|object, [key, [value,]] callback);
Remove a node/relationship from a legacy index.
NOTE for legacy index functions: there are two different types of legacy
index in neo4j - node legacy indexes and relationship legacy indexes.
When you're working with node legacy indexes, you use the functions on
node.legacyindex
. Similarly, when you're working on relationship legacy
indexes you use the functions on rel.legacyindex
. Most of the functions on
both of these are identical (excluding the uniqueness functions), but one acts
upon node legacy indexes, and the other upon relationship legacy indexes.
Arguments
indexName
- the legacy index to remove the node/relationship from.id | object
- the id of the node/relationship to remove from the legacy index or an object with an id property of the node/relationship to remove from the legacy index.key
(optional) - the key from which to remove the node/relationship. If none is specified, every reference to the node/relationship is deleted from the legacy index.value
(optional) - the value from which to remove the node/relationship. If none is specified, every reference to the node/relationship is deleted for the given key.callback
- function(err). Iferr
is falsy, the specified references have been removed.
Example
db.node.legacyindex.remove('people', 6821, function(err) {
if (!err) console.log("Every reference of node 6821 has been removed from the people index");
});
db.rel.legacyindex.remove('friendships', 351, 'in', 'Australia', function(err) {
if (!err) console.log("Relationship 351 is no longer indexed as a friendship in Australia");
})
node.legacyindex.delete(name, callback);
rel.legacyindex.delete(name, callback);
Delete a legacy index.
NOTE for legacy index functions: there are two different types of legacy
index in neo4j - node legacy indexes and relationship legacy indexes.
When you're working with node legacy indexes, you use the functions on
node.legacyindex
. Similarly, when you're working on relationship legacy
indexes you use the functions on rel.legacyindex
. Most of the functions on
both of these are identical (excluding the uniqueness functions), but one acts
upon node legacy indexes, and the other upon relationship legacy indexes.
Arguments
name
- the name of the legacy index to deletecallback
- function(err). iferr
is falsy, the legacy index has been deleted.
Example
db.rel.legacyindex.delete('friendships', function(err) {
if (!err) console.log('The `friendships` index has been deleted');
});
node.legacyindex.getOrSaveUnique(node, index, key, value, callback);
rel.legacyindex.getOrSaveUnique(startNode, relName, endNode, [properties,] index, key, value, callback);
Save a node or relationship, using a legacy index to enforce uniqueness. If
there is already a node or relationship saved under the specified key
and
value
in the specified index
, that node or relationship will be returned.
Note that you cannot use this function to update nodes.
NOTE for legacy index functions: there are two different types of legacy
index in neo4j - node legacy indexes and relationship legacy indexes.
When you're working with node legacy indexes, you use the functions on
node.legacyindex
. Similarly, when you're working on relationship legacy
indexes you use the functions on rel.legacyindex
. Most of the functions on
both of these are identical (excluding the uniqueness functions), but one acts
upon node legacy indexes, and the other upon relationship legacy indexes.
Arguments (node)
node
- the node to saveindex
- the name of the legacy index in whichkey
andvalue
are relevantkey
- the key to check or store undervalue
- the value to check or store undercallback
- function(err, node) - returns your saved node, or the node that was referenced by the specifiedkey
andvalue
if one already existed.
Arguments (relationship)
startNode
- the start point of the relationship (object containing id or id)relName
- the name of the relationship to createendNode
- the end point of the relationship (object containing id or id)properties
(optional) - an object containing properties to store on the created relationship.index
- the name of the legacy index in whichkey
andvalue
are relevantkey
- the key to check or store undervalue
- the value to check or store undercallback
- function(err, rel) - returns your created relationship, or the relationship that was referenced by the specifiedkey
andvalue
if one already existed.
Example
var tag = { name: 'finnish' };
db.node.legacyindex.getOrSaveUnique(tag, 'tags', 'name', tag.name, function(err, tag) {
// tag == { id: 1, name: 'finnish' }
// save another new object with the same properties
db.node.legacyindex.getOrSaveUnique({ name: 'finnish' }, 'tags', 'name', 'finnish', function(err, newTag) {
// newTag == { id: 1, name: 'finnish' }
// no save was performed because there was already an object at that index
});
});
node.legacyindex.saveUniqueOrFail(node, index, key, value, callback);
rel.legacyindex.saveUniqueOrFail(startNode, relName, endNode, [properties,] index, key, value, callback);
Save a node or relationship, using a legacy index to enforce uniqueness. If
there is already a node or relationship saved under the specified key
and
value
in the specified index
, an error is returned indicating that there
as a conflict. You can check if the result was a conflict by checking if
err.statusCode == 409
.
NOTE for legacy index functions: there are two different types of legacy
index in neo4j - node legacy indexes and relationship legacy indexes.
When you're working with node legacy indexes, you use the functions on
node.legacyindex
. Similarly, when you're working on relationship legacy
indexes you use the functions on rel.legacyindex
. Most of the functions on
both of these are identical (excluding the uniqueness functions), but one acts
upon node legacy indexes, and the other upon relationship legacy indexes.
Arguments (node)
node
- the node to saveindex
- the name of the legacy index in whichkey
andvalue
are relevantkey
- the key to check or store undervalue
- the value to check or store undercallback
- function(err, node) - returns your created node, or an err withstatusCode == 409
if a node already existed at that legacy index
Arguments (relationship)
startNode
- the start point of the relationship (object containing id or id)relName
- the name of the relationship to createendNode
- the end point of the relationship (object containing id or id)properties
(optional) - an object containing properties to store on the created relationship.index
- the name of the legacy index in whichkey
andvalue
are relevantkey
- the key to check or store undervalue
- the value to check or store undercallback
- function(err, rel) - returns your created relationship, or an err withstatusCode == 409
if a relationship already existed at that legacy index
Example
var tag = { name: 'finnish' };
db.node.legacyindex.saveUniqueOrFail(tag, 'tags', 'name', tag.name, function(err, tag) {
// tag == { id: 1, name: 'finnish' }
// save another new object with the same properties
db.node.legacyindex.saveUniqueOrFail({ name: 'finnish' }, 'tags', 'name', 'finnish', function(err, newTag) {
// newTag == undefined
// err.statusCode == 409 (conflict)
// an error was thrown because there was already a node at that index.
});
});
Development of Seraph is lovingly sponsored by BRIK Tekonologier AS in Bergen, Norway.