This document discusses using JavaScript in databases. It describes how JavaScript can be used in the database for transactions defined as functions, graph traversal, and having no backend code, just an API. It provides examples of using JavaScript for transactions and graph traversal in ArangoDB.

1. JavaScript in the Database
Frank Celler & Lucas Dohmen
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2. The NoSQL Movement
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3. CAP
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ACID
BASE
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4. www.arangodb.org (c) f.celler@triagens.de
nosql.eventbrite.com
distributed structured
data storage
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5. Your Entities
A Person has a
Name, first and last
one or more addresses, emails,
telephone
a list of hobbies, skills, tags
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6. Relational World
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PersonPersonPerson
AddressAddressAddress
HobbyHobbyHobby
emailemailemail
n-to-mn-to-mn-to-m
n-to-mn-to-mn-to-m
n-to-mn-to-mn-to-m
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7. Use Aggregates
Do not Normalize
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{ name: { first: „Frank“, last: „Celler“ },
address: { home: { street: „...“, city: „...“ } },
email: { work: „frank@celler.de“ },
hobbies: [ „C++“, „MRuby“, „JavaScript“ ] }
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8. Document Databases
documents can be
as simple as key/value maps
or as complex as lists containing embedded
sub-documents
or anything in between
representated in JSON
Schema-less
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9. www.arangodb.org (c) f.celler@triagens.de 9
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10. www.arangodb.org (c) f.celler@triagens.de 10
Analytic Processing DBsTransaction Processing DBs
Managing the evolving state of an IT system
Map/Reduce
Graphs
Extensibility
Key/Value
Column-
Stores
Complex
Queries
Structured
Data
Massively
Distributed
Documents
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11. Property Graphs
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Type: inproceeding
Title: Finite Size Effects
Type: proceeding
Title: Neural Modeling
Type: person
Name: Anthony C. C. Coolen
Label: written
Label: published
Pages: 99-120
Type: person
Name: Snchez-Andrs
Label: edited
Just Documents
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12. Multi-Model Databases
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vertices and edges are documents
query them using geo-index, full-text,
SQL-like queries
relations are expressed as graphs
traverse them using graph algorithms
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13. ArangoDB.explain()
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{
"type": "NoSQL database",
"model": [ "document", "graph", "key-value" ],
"openSource": true,
"license“: "apache",
"version": 1.3,
"builtWith": [ "C", "C++", "js" ],
"Javascript": [ "client side", "server side" ],
"uses": [ "V8" ]
}
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14. Why Use JavaScript?
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15. JavaScript Everywhere
in the Browser
Application-Layer (Node.JS)
Database
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16. Why is Node not enough?
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17. JavaScript in a Database
MVC in the Browser and/or NODE.JS
Script-Language in the DB for
transactions as functions
graph traversal
no-backend, just API
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18. db._create("accounts");
db.accounts.save({ _key: "john", amount: 423 });
db.accounts.save({ _key: "fred", amount: 197 });
db._executeTransaction({
collections: {
write: "accounts"
},
params: {
user1: "fred",
user2: "john",
amount: 10
},
action: function (params) {
var db = require("internal").db;
var account1 = db.accounts.document(params['user1']);
var account2 = db.accounts.document(params['user2']);
var amount = params['amount'];
if (account1.amount < amount) {
throw "account of user '" + user1 + "' does not have enough money!";
}
db.accounts.update(account1, { amount : account1.amount - amount });
db.accounts.update(account2, { amount : account2.amount + amount });
/* will commit the transaction and return the value true */
return true;
}
});
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Transactions
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19. db._executeTransaction({
collections: {
write: "accounts"
},
params: {
user1: "fred",
user2: "john",
amount: 10
},
action: function (params) {
var db = require("internal").db;
var account1 = db.accounts.document(params['user1']);
var account2 = db.accounts.document(params['user2']);
var amount = params['amount'];
if (account1.amount < amount) {
throw "account of user '" + user1 + "' does not have enough money!";
}
db.accounts.update(account1, { amount : account1.amount - amount });
db.accounts.update(account2, { amount : account2.amount + amount });
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Transactions
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20. function traverse (graph, start, depth, maxlen) {
var config = {
datasource: traversal.collectionDatasourceFactory(graph._edges),
strategy: Traverser.BREADTH_FIRST,
expander: traversal.anyExpander,
filter: traversal.maxDepthFilter,
maxDepth: depth,
uniqueness: { edges: Traverser.UNIQUE_GLOBAL, vertices: Traverser.UNIQUE_NONE },
visitor: coauthorVisitor(maxlen)
};
var traverser = new Traverser(config);
var result = { positions: {}, vertices: [], links: [], minYear: 0, maxYear: 0 };
var first = graph._vertices.firstExample({ name: start });
if (first !== null) {
traverser.traverse(result, first);
}
return {
start: start,
depth: depth,
minYear: result.minYear,
maxYear: result.maxYear,
vertices: result.vertices,
links: result.links };
}
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Graph Traversal
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21. function traverse (graph, start, depth, maxlen) {
var config = {
datasource: traversal.collectionDatasourceFactory(graph._edges),
strategy: Traverser.BREADTH_FIRST,
expander: traversal.anyExpander,
filter: traversal.maxDepthFilter,
maxDepth: depth,
uniqueness: { edges: Traverser.UNIQUE_GLOBAL,
vertices: Traverser.UNIQUE_NONE },
visitor: coauthorVisitor(maxlen)
};
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Graph Traversal
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22. No Back-End?
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23. To Be Continued ... Now
Fork me on github
Google Group: ArangoDB
Twitter: @fceller & @arangodb
www.arangodb.org
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Stay in Touch:
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