Voyage. NoSQL Object Database. Damien Cassou, Stéphane Ducasse and Luc Fabresse. W4S11

Transcription

1 Voyage NoSQL Object Database Damien Cassou, Stéphane Ducasse and Luc Fabresse W4S11

2 W4S11 2 / 27 Goal To let you build a real little application Show you a nice way to store objects

3 W4S11 3 / 27 MongoDB Document oriented, open-source NoSQL database Powerful query language Most popular document database so far

4 W4S11 4 / 27 What is Voyage? Object-Document Mapper for MongoDB Think on Hibernate for MongoDB For Pharo, obviously ;)

5 W4S11 5 / 27 Voyage Feature Simple Ensure object identity Provide error-handling Implement a connection pool

6 Setting a Connexion W4S11 6 / 27 repository repository := VOMongoRepository host: 'localhost' database: 'demo'. repository enablesingleton.

7 W4S11 7 / 27 Setting a In Memory Connexion repository repository := VOMemoryRepository new. repository enablesingleton. Really nice to prototype Then can easily switch to a MongoDB

8 A Simple Model W4S11 8 / 27

9 A Simpler Model W4S11 9 / 27

10 A Simpler Model Object subclass: #Hero instancevariablenames: 'name level powers' classvariablenames: '' package: 'SuperHeroes' Hero >> name ^ name Hero >> name: astring name := astring Hero >> level ^ level Hero >> level: anobject level := anobject Hero >> powers ^ powers ifnil: [ powers := Set new ] Hero >> addpower: apower self powers add: apower W4S11 10 / 27

11 A Simpler Model W4S11 11 / 27 Object subclass: #Power instancevariablenames: 'name' classvariablenames: '' package: 'SuperHeroes'. Power>>name ^ name Power>>name: astring name := astring

12 W4S11 12 / 27 Root Classes Entry-point for our database Can be any class in the system Marked as root by isvoyageroot class method

13 Root Classes W4S11 13 / 27 Hero class >> isvoyageroot ^ true

14 Some Heroes W4S11 14 / 27 Hero new name: 'Spiderman'; level: #epic; addpower: (Power new name: 'Super strength'); addpower: (Power new name: 'Wall climbing'); addpower: (Power new name: 'Spider instinct'); save. Hero new name: 'Wolverine'; level: #epic; addpower: (Power new name: 'Regeneration'); addpower: (Power new name: 'Adamantium claws'); save.

15 In DB > db.hero.find()[0] { "_id" : ObjectId("d847065c56d0ad09b "), "#version" : , "#instanceof" : "Hero", "level" : "epic", "name" : "Spiderman", "powers" : [ { "#instanceof" : "Power", "name" : "Spider instinct" }, { "#instanceof" : "Power", "name" : "Super strength" }, { "#instanceof" : "Power", W4S11 15 / 27

16 Querying W4S11 16 / 27 Hero selectall. > an OrderedCollection(a Hero, a Hero) Hero selectone: [ :each each name = 'Spiderman' ]. > a Hero Hero selectmany: [ :each each level = #epic ]. > an OrderedCollection(a Hero, a Hero)

17 Querying 2 W4S11 17 / 27 Hero selectone: { #name > 'Spiderman' } asdictionary. > a Hero Hero selectmany: { #level > #epic } asdictionary. > an OrderedCollection(a Hero, a Hero)

18 Querying 3 W4S11 18 / 27 Hero selectmany: { #level > #epic } asdictionary sortby: { #name > VOOrder ascending } limit: 10 offset: 0. > an OrderedCollection(a Hero, a Hero)

19 Some Operations W4S11 19 / 27 Hero count. > 2 Hero count: [ :each each name = 'Spiderman' ] > 1. Hero removeall. "Beware of this!" > Hero class hero := Hero selectall anyone. hero remove. > a Hero

20 W4S11 20 / 27 Defining Document Roots If you want to query them If you want to share objects between roots

21 W4S11 21 / 27 Defining Document Roots Yes, Hero is a root on the example Power can be a root too (you can share powers between heroes) Any class can be declared as root, Voyage will manage it automatically

22 Defining Document Roots W4S11 22 / 27 Power class >> isvoyageroot ^ true Power new name: 'Fly'; save. Power new name: 'Super strength'; save. fly := Power selectone: [ :each each name = 'Fly']. superstrength := Power selectone: [ :each each name = 'Super strength']. Hero new name: 'Superman'; level: #epic; addpower: fly; addpower: superstrength; save.

23 Important W4S11 23 / 27 Reset repository when changing the schema VORepository current reset.

24 In DB > db.hero.find()[0] { "_id" : ObjectId("d aa909b "), "#version" : NumberLong(" "), "#instanceof" : "Hero", "level" : "epic", "name" : "Superman", "powers" : [ { "#collection" : "Power", "#instanceof" : "Power", " id" : ObjectId("d84745dd421aa909b ") }, { "#collection" : "Power", "#instanceof" : "Power", " id" : ObjectId("d84745dd421aa909b ") } W4S11 24 / 27

25 W4S11 25 / 27 Relationships Root references (kind of foreign keys ) Voyage handles cyclic references of root objects Beware, Voyage does not support cyclic references of embedded objects (yet)

26 W4S11 26 / 27 Conclusion We can easily save objects in MongoDB More information in Entreprise Pharo: a Web Perspective

27 A course by and in collaboration with Inria 2016 Except where otherwise noted, this work is licensed under CC BY-NC-ND 3.0 France