arangodb - using javascript in the database

ArangoDB

/* Using Javascriptin the database */

Jan Steemann, triAGENS, Cologne

www.arangodb.org © [email protected]

ArangoDBbasics


ArangoDB.explain()

{ "type": "NoSQL database", "openSource": true, "version": 1.0, "builtWith": [ "C", "C++", "js" ], "Javascript": [ "client side", "server side" ], "uses": [ "V8" ]}


Documentsand collections

ArangoDB is a database that works with documents

Documents are sets of name / value pairs (think of JSON objects), e.g.

{ "name": "Jan", "age": 37 }

Documents are organised in collections (like tables in relational databases)


Data types: JSON!

ArangoDB operates on JSON documents

JSON data can be saved as-is:

db.users.save({ "name": "Jan", "uses": [ "vi", "js", "C++" ]});


Schema-freeDocuments can be heterogenous – even in the same collection, e.g.

{ "name": "Jan", "age": 37 },{ "name": "Tim", "likes": [ "js" ] },{ "name": { "first": "Patrick", "last": "Star" }}

No need to care about schemas


API & protocolsArangoDB server functionality is exposed via an HTTP REST API

ArangoDB answers HTTP queries, so it can be used from the browser

Simple to use from Javascript clients

(3rd party) drivers available for node.js, Ruby, PHP, ...

Javascript-enabled client shell provided


Querying


Querying is simple

Query a document by its unique id / key:db._document("users/9558905");

Query by providing an example:db.users.byExample({ "name": "Jan", "age": 37});


Indexes

ArangoDB allows querying on any document attributes or sub-attributes

Secondary indexes can be created for higher query performance:

• Hash indexes (equality queries)

• Skiplists (range queries)

• 2d geo indexes (location queries)


Geo index examples

// get b a r n ea r es t t o coor din a t edb.bars.near(48.51, 2.21).limit(1);

// get a ll s h op s w it h in r a diu s// a r ou n d coor din a t edb.shops.within(48.51, 2.21, rad);


References

ArangoDB can store references between documents

References are documents with two endpoints (the documents they connect)

Reference documents can carry own attributes


References exampleUsers documents:

{ "name": "Jan", "age": 37} { "name": "Tim", "city": "Paris"}

Relations documents:(references)

{ "_from": "users/jan", "_to": "users/tim", "type": "knows",}

// qu er y ou t b ou n d r ela t ion s f r om "J a n "db.relations.outEdges(jan); // => tim


Graph queries

References make it possible to process graphs with ArangoDB

Some special functions are provided to determine paths in a graph etc.

Can write own Javascript functions for special traversals


Query language

ArangoDB can also answer complexSQL-like queries

Such queries are expressed in ArangoDB's textual query language

This language allows joins, sub-queries, aggregation etc.


Example queryFOR u IN users FILTER u.addr.country == "US" && (u.isConfirmed == true || u.age >= 18) LET userLogins = ( FOR l IN logins FILTER l.userId == u.id RETURN l ) RETURN { "user": u, "logins": LENGTH(userLogins) }

S u b qu er y

R es u lt

F ilt er

It er a t or


Server side „actions“


Application server

ArangoDB can answer web requests directly

This also makes it an application server

Users can extend its functionality with server side Javascript „actions“

Actions are user-defined functions that contain custom business logic


Actions

Actions are bound to URLs and executed when URLs are called, e.g.

/users?name=... => function(...)/users/.../friends => function(...)


Actions examplefunction (req, res) { // get r equ es t ed u s er f r om d b , // n a m e is r ea d f r om U R L p a r a m et er var u = db.users.byExample({ "username": req.urlParameters.name });

// r em ov e p a s s w or d h a s h delete u.hashedPassword;

// b ef or e r et u r n in g t o ca ller actions.resultOk(req, res, 200, u);}


Actions – Use casesFilter out sensitive data before responding

Validate input

Check privileges

Check and enforce constraints

Aggregate data from multiple queries into a single response

Carry out data-intensive operations


Summary


ArangoDB - summary

Flexible in terms of data modelling and querying

API is based on web standards:HTTP, REST, JSON

Easy to use from Javascript clients

Can be used as application server

Functionality can be extended with server side Javascript „actions“


Thanks!Any questions?

Grazie

¡Gracias!

Хвала

Ευχαριστώ

고마워

Danke

Спасибо

Teşekkürler

Merci!

Dank je wel

ありがとう

Tack så mycket


Give it a try!ArangoDB source repository: https://www.github.com/triAGENS/ArangoDB(use master branch)

Website: http://www.arangodb.org/

Builds available for Homebrew and several Linux distributions

Twitter: #arangodb, @arangodb

Google group: ArangoDB


Roadmap

MVCC / ACID transactions

Triggers

Synchronous and asynchronous replication


Stay in Touch:

• Fork me on github

• Google Group: ArangoDB

• Twitter: @steemann & @arangodb

• www.arangodb.org

Thank you!

arangodb - using javascript in the database

Technology