loopback-connector-mysql

loopback-connector-mysql is the MySQL connector module for loopback-datasource-juggler.

Usage

To use it you need loopback-datasource-juggler.

1. Setup dependencies in package.json:

   {
     ...
     "dependencies": {
       "loopback-datasource-juggler": "latest",
       "loopback-connector-mysql": "latest"
     },
     ...
   }
   

2. Use:

       var DataSource = require('loopback-datasource-juggler').DataSource;
       var dataSource = new DataSource('mysql', {
           host: 'localhost',
           port: 3306,
           database: 'mydb',
           username: 'myuser',
           password: 'mypass'
       });
   

   You can optionally pass a few additional parameters supported by node-mysql, most particularly password and collation. Collation currently defaults to utf8_general_ci. The collation value will also be used to derive the connection charset.

Data type mappings

loopback-connector-mysql uses the following rules to map between JSON types and MySQL data types.

JSON to MySQL types

• String/JSON: VARCHAR
• Text: TEXT
• Number: INT
• Date: DATETIME
• BOOLEAN: TINYINT(1)
• Point/GeoPoint: POINT
• Enum: ENUM

MySQL to JSON types

• CHAR: String
• CHAR(1): Boolean
• VARCHAR/TINYTEXT/MEDIUMTEXT/LONGTEXT/TEXT/ENUM/SET: String
• TINYBLOB/MEDIUMBLOB/LONGBLOB/BLOB/BINARY/VARBINARY/BIT: Binary
• TINYINT/SMALLINT/INT/MEDIUMINT/YEAR/FLOAT/DOUBLE/NUMERIC/DECIMAL: Number
• DATE/TIMESTAMP/DATETIME: Date

Using the dataType field/column option with MySQL

loopback-connector-mysql allows mapping of LoopBack model properties to MYSQL columns using the 'mysql' property of the property definition. For example,

"locationId":{
    "type":"String",
    "required":true,
    "length":20,
    "mysql":
    {
        "columnName":"LOCATION_ID",
        "dataType":"VARCHAR2",
        "dataLength":20,
        "nullable":"N"
    }
}

loopback-connector-mysql also supports using the dataType column/property attribute to specify what MySQL column type is used for many loopback-datasource-juggler types.

The following type-dataType combinations are supported:

• Number

  • integer

    • tinyint
    • smallint
    • mediumint
    • int
    • bigint

    Use the limit option to alter the display width.

    Example: { count : { type: Number, dataType: 'smallInt' }}

  • floating point types

    • float
    • double

    Use the precision and scale options to specify custom precision. Default is (16,8).

    Example: { average : { type: Number, dataType: 'float', precision: 20, scale: 4 }}

  • fixed-point exact value types

    • decimal
    • numeric

    Use the precision and scale options to specify custom precision. Default is (9,2).

    These aren't likely to function as true fixed-point.

    Example: { stdDev : { type: Number, dataType: 'decimal', precision: 12, scale: 8 }}

• String / DataSource.Text / DataSource.JSON

  • varchar
  • char
  • text
  • mediumtext
  • tinytext
  • longtext

  Example: { userName : { type: String, dataType: 'char', limit: 24 }}

  Example: { biography : { type: String, dataType: 'longtext' }}

• Date

  • datetime
  • timestamp

  Example: { startTime : { type: Date, dataType: 'timestamp' }}

• Enum Enums are special. Create an Enum using Enum factory:

    var MOOD = dataSource.EnumFactory('glad', 'sad', 'mad');
    MOOD.SAD;    // 'sad'
    MOOD(2);     // 'sad'
    MOOD('SAD'); // 'sad'
    MOOD('sad'); // 'sad'

• { mood: { type: MOOD }}
• { choice: { type: dataSource.EnumFactory('yes', 'no', 'maybe'), null: false }}

Discovering Models

MySQL data sources allow you to discover model definition information from existing mysql databases. See the following APIs:

• dataSource.discoverModelDefinitions([owner], fn)
• dataSource.discoverSchema([owner], name, fn)

Asynchronous APIs for discovery

• MySQL.prototype.discoverModelDefinitions = function (options, cb)

  • options:
    • all: {Boolean} To include tables/views from all schemas/owners
    • owner/schema: {String} The schema/owner name
    • views: {Boolean} To include views
  • cb:

    • Get a list of table/view names, for example:

      {type: 'table', name: 'INVENTORY', owner: 'STRONGLOOP' } {type: 'table', name: 'LOCATION', owner: 'STRONGLOOP' } {type: 'view', name: 'INVENTORY_VIEW', owner: 'STRONGLOOP' }

• MySQL.prototype.discoverModelProperties = function (table, options, cb)

  • table: {String} The name of a table or view
  • options:
    • owner/schema: {String} The schema/owner name
  • cb:

    • Get a list of model property definitions, for example:

      { owner: 'STRONGLOOP',
        tableName: 'PRODUCT',
        columnName: 'ID',
        dataType: 'VARCHAR2',
        dataLength: 20,
        nullable: 'N',
        type: 'String' }
      { owner: 'STRONGLOOP',
        tableName: 'PRODUCT',
        columnName: 'NAME',
        dataType: 'VARCHAR2',
        dataLength: 64,
        nullable: 'Y',
        type: 'String' }
      

• MySQL.prototype.discoverPrimaryKeys= function(table, options, cb)

  • table: {String} The name of a table or view
  • options:
    • owner/schema: {String} The schema/owner name
  • cb:

    • Get a list of primary key definitions, for example:

      { owner: 'STRONGLOOP', tableName: 'INVENTORY', columnName: 'PRODUCT_ID', keySeq: 1, pkName: 'ID_PK' } { owner: 'STRONGLOOP', tableName: 'INVENTORY', columnName: 'LOCATION_ID', keySeq: 2, pkName: 'ID_PK' }

• MySQL.prototype.discoverForeignKeys= function(table, options, cb)

  • table: {String} The name of a table or view
  • options:
    • owner/schema: {String} The schema/owner name
  • cb:

    • Get a list of foreign key definitions, for example:

      { fkOwner: 'STRONGLOOP', fkName: 'PRODUCT_FK', fkTableName: 'INVENTORY', fkColumnName: 'PRODUCT_ID', keySeq: 1, pkOwner: 'STRONGLOOP', pkName: 'PRODUCT_PK', pkTableName: 'PRODUCT', pkColumnName: 'ID' }

• MySQL.prototype.discoverExportedForeignKeys= function(table, options, cb)

  • table: {String} The name of a table or view
  • options:
    • owner/schema: {String} The schema/owner name
  • cb:

    • Get a list of foreign key definitions that reference the primary key of the given table, for example:

      { fkName: 'PRODUCT_FK', fkOwner: 'STRONGLOOP', fkTableName: 'INVENTORY', fkColumnName: 'PRODUCT_ID', keySeq: 1, pkName: 'PRODUCT_PK', pkOwner: 'STRONGLOOP', pkTableName: 'PRODUCT', pkColumnName: 'ID' }

Discover/build/try the models

Build a LDL schema by discovery

Data sources backed by the MySQL connector can discover LDL models from the database using the discoverSchema API. For example,

dataSource.discoverSchema('INVENTORY', {owner: 'STRONGLOOP'}, function (err, schema) {
    ...
}

Here is the sample result. Please note there are 'mysql' properties in addition to the regular LDL model options and properties. The 'mysql' objects contain the MySQL specific mappings.

{
  "name":"Inventory",
  "options":{
    "idInjection":false,
    "mysql":{
      "schema":"STRONGLOOP",
      "table":"INVENTORY"
    }
  },
  "properties":{
    "productId":{
      "type":"String",
      "required":false,
      "length":60,
      "precision":null,
      "scale":null,
      "id":1,
      "mysql":{
        "columnName":"PRODUCT_ID",
        "dataType":"varchar",
        "dataLength":60,
        "dataPrecision":null,
        "dataScale":null,
        "nullable":"NO"
      }
    },
    "locationId":{
      "type":"String",
      "required":false,
      "length":60,
      "precision":null,
      "scale":null,
      "id":2,
      "mysql":{
        "columnName":"LOCATION_ID",
        "dataType":"varchar",
        "dataLength":60,
        "dataPrecision":null,
        "dataScale":null,
        "nullable":"NO"
      }
    },
    "available":{
      "type":"Number",
      "required":false,
      "length":null,
      "precision":10,
      "scale":0,
      "mysql":{
        "columnName":"AVAILABLE",
        "dataType":"int",
        "dataLength":null,
        "dataPrecision":10,
        "dataScale":0,
        "nullable":"YES"
      }
    },
    "total":{
      "type":"Number",
      "required":false,
      "length":null,
      "precision":10,
      "scale":0,
      "mysql":{
        "columnName":"TOTAL",
        "dataType":"int",
        "dataLength":null,
        "dataPrecision":10,
        "dataScale":0,
        "nullable":"YES"
      }
    }
  }
}

We can also discover and build model classes in one shot. The following example uses discoverAndBuildModels to discover, build and try the models:

dataSource.discoverAndBuildModels('INVENTORY', { owner: 'STRONGLOOP', visited: {}, associations: true},
     function (err, models) {
        // Show records from the models
        for(var m in models) {
            models[m].all(show);
        };

        // Find one record for inventory
        models.Inventory.findOne({}, function(err, inv) {
            console.log("\nInventory: ", inv);
            // Follow the foreign key to navigate to the product
            inv.product(function(err, prod) {
                console.log("\nProduct: ", prod);
                console.log("\n ------------- ");
            });
    });
}

License

The MIT license.

The project was initially forked from mysql-adapter which carries the following copyright and permission notices:

Copyright (C) 2012 by Anatoliy Chakkaev

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.