137 lines
4.5 KiB
Markdown
137 lines
4.5 KiB
Markdown
# LoopBack DataSource Juggler
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LoopBack DataSource Juggler is an ORM that provides a common set of interfaces
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for interacting with databases, REST APIs, and other data sources. It was
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initially forked from [JugglingDB](https://github.com/1602/jugglingdb).
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## Overview
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LoopBack DataSource Juggler consists of the following components:
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* LoopBack Definition Language
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* DataSource
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* Connector
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## LoopBack Definition Language
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To define model dataSource have single method `dataSource.define`. It accepts
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three arguments:
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* **model name**:
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String name in camel-case with first upper-case letter. This name will be
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used later to access model.
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* **properties**:
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Object with property type definitions. Key is property name, value is type
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definition. Type definition can be function representing type of property
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(String, Number, Date, Boolean), or object with {type: String|Number|...,
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index: true|false} format.
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* **settings**:
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Object with model-wide settings such as `tableName` or so.
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Examples of model definition:
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var User = dataSource.define('User', {
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email: String,
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password: String,
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birthDate: Date,
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activated: Boolean
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});
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var User = dataSource.define('User', {
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email: { type: String, limit: 150, index: true },
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password: { type: String, limit: 50 },
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birthDate: Date,
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registrationDate: {
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type: Date,
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default: function () { return new Date }
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},
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activated: { type: Boolean, default: false }
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}, {
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tableName: 'users'
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});
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## DataSource
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DataSource is a factory for model classes. DataSource connected with specific
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database or other backend system using connector.
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All model classes within single datasource shares same connector type and one
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database connection. But it's possible to use more than one datasource to
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connect with different databases.
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### Creating dataSource
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`DataSource` constructor available on `loopback-datasource-juggler` module:
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var DataSource = require('loopback-datasource-juggler').DataSource;
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DataSource constructor accepts two arguments. First argument is connector. It
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could be a connector name or connector package:
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var dataSourceByConnectorName = new DataSource('memory');
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var dataSourceByConnectorModule = new DataSource(require('redis'));
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### Settings
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Second argument is optional settings. Settings object format and defaults
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depends on specific connector, but common fields are:
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* `host`: Database host
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* `port`: Database port
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* `username`: Username to connect to database
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* `password`: Password to connect to database
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* `database`: Database name
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* `debug`: Turn on verbose mode to debug db queries and lifecycle
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For connector-specific settings refer to connector's readme file.
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## LoopBack Connectors
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| Type | Package Name |
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| --------- |:--------------------------------------------------------------------------------------:|
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| MongoDB | [loopback-connector-mongodb](https://github.com/strongloop/loopback-connector-mongodb) |
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| Oracle | [loopback-connector-oracle](https://github.com/strongloop/loopback-connector-oracle) |
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| MySQL | [loopback-connector-mysql](https://github.com/strongloop/loopback-connector-mysql) |
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LoopBack connectors provide access to backend systems including databases,
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REST APIs and other services. Connectors are not used directly by application
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code. We create a DataSource to interact with the connector.
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For example,
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var DataSource = require('loopback-datasource-juggler').DataSource;
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var oracleConnector = require('loopback-connector-oracle');
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var ds = new DataSource(oracleConnector, {
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host : '127.0.0.1',
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database : 'XE',
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username : 'strongloop',
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password : 'password',
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debug : true
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});
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The connector argument passed the DataSource constructor can be one of the
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following:
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* The connector module from `require(connectorName)`
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* The full name of the connector module, such as 'loopback-connector-oracle'
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* The short name of the connector module, such as 'oracle', which will be
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converted to 'loopback-connector-<shortName>'
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* A local module under ./connectors/<connectorName> folder
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## Installation
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npm install loopback-datasource-juggler
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Also install the appropriated connector, for example for mongodb:
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npm install loopback-connector-mongodb
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check following list of available connectors
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