dexie-relationships


Dexie.js relationship plugin
========

Dexie.js is a wrapper library for indexedDB - the standard database in the browser.

Dexie relationship plugin provides an API to ease the loading of relational data from foreign tables

Installation
========

npm:
``
npm install dexie-relationships --save
`

bower:
`
bower install dexie-relationships --save
`

API Example
========

#### Schema
Note the use of -> which sets the foreign keys.

`javascript
import Dexie from 'dexie'
import relationships from 'dexie-relationships'

var db = new Dexie('MusicBands', {addons: [relationships]})

db.version(1).stores({
genres: 'id, name',
bands: 'id, name, genreId -> genres.id',
albums: 'id, name, bandId -> bands.id, year'
});

`

#### Seed the data

`javascript
db.transaction('rw', db.bands, db.albums, db.genres, () => {
// Genres
db.genres.bulkPut([{
id: 1,
name: "Rock"
},{
id: 2,
name: "Schlager"
}])

// Bands
db.bands.bulkPut([{
id: 1,
name: 'Beatles',
genreId: 1
},{
id: 2,
name: 'Abba',
genreId: 2
}])

// Albums
db.albums.bulkPut([{
id: 1,
name: 'Abbey Road',
year: 1969,
bandId: 1
}, {
id: 2,
name: 'Let It Be',
year: 1970,
bandId: 1
}, {
id: 3,
name: 'Super Trouper',
bandId: 2,
year: 1980
}, {
id: 4,
name: 'Waterloo',
bandId: 2,
year: 1974
}])
})
`

#### Usage

`javascript
db.bands
.where('name').startsWithAnyOf('A', 'B') // can be replaced with your custom query
.with({albums: 'albums', genre: 'genreId'}) // makes referred items included
.then(bands => {
// Let's print the result:
bands.forEach (band => {
console.log (Band Name: ${band.name})
console.log (Genre: ${band.genre.name})
console.log (Albums: ${JSON.stringify(band.albums, null, 4)})
});
})
`

*NOTE: The properties that are set onto the result ('albums' and 'genre' in this case)
will not be visible when callilng JSON.stringify(band), because
they are marked as non-enumerable. The reason for this is to prevent the properties to be
redundantly stored back to the database if calling db.bands.put(band).*

#### Result

`
Band Name: Abba
Genre: Schlager
Albums: [
{
"id": 3,
"name": "Super Trouper",
"bandId": 2,
"year": 1980
},
{
"id": 4,
"name": "Waterloo",
"bandId": 2,
"year": 1974
}
]
Band Name: Beatles
Genre: Rock
Albums: [
{
"id": 1,
"name": "Abbey Road",
"year": 1969,
"bandId": 1
},
{
"id": 2,
"name": "Let It Be",
"year": 1970,
"bandId": 1
}
]
``