ezobjects-mysql

EZ Objects - MySQL Edition - v3.0.0

EZ Objects (MySQL Edition) is a Node.js module (that can also be usefully browserify'd) that aims to save you lots of time writing class objects that are strictly typed in JavaScript, and can be tied directly to MySQL database tablesby way of a mix of insert/update/load/delete class method signatures. All you have to do is create simple class configurations for each of your objects and then create them using the createClass() function.

• Installation
• Basic Example
• Basic EZ Object Method Signatures
• MySQL EZ Object Method Signatures
• Module Exports
• Configuration Specifications
• Contributing
• License

Installation

npm install --save ezobjects-mysql

Basic Example

Important Notes: Your object must have a unique integer property named id to be able to use the MySQL functionality of EZ Objects. You must also use EZ Object's MySQLConnection class for your database connection.

const ezobjects = require(`ezobjects-mysql`);
const fs = require(`fs`);

/** 
 * Load external MySQL configuration which uses the following JSON 
 * format:
 * {
 *   "host"          : "localhost",
 *   "user"          : "ezobjects",
 *   "password"      : "myPassword",
 *   "database"      : "ezobjects"
 * }
 */
const configMySQL = JSON.parse(fs.readFileSync(`mysql-config.json`));

/** 
 * Create a connection object for the MySQL database using our MySQL 
 * module async/await wrapper.
 */
const db = new ezobjects.MySQLConnection(configMySQL);

/** 
 * Configure a new EZ Object called DatabaseRecord with the required 
 * `id` property that will serve as the auto-incrementing primary index.
 */
const configDatabaseRecord = {
  className: `DatabaseRecord`,
  properties: [
    { name: `id`, type: `int` }
  ]
};

/** 
 * Create the DatabaseRecord object -- Note: This object is not linked
 * to a MySQL table directly, as it has no `tableName` property, but
 * it can be extended by EZ Objects that are linked to tables.
 */
ezobjects.createClass(configDatabaseRecord);

/** 
 * Configure a new EZ Object called UserAccount that extends from the 
 * DatabaseRecord object and adds several additional properties,
 * including an array of `int` property and a MySQL index.
 */
const configUserAccount = {
  tableName: `user_accounts`,
  className: `UserAccount`,
  extends: DatabaseRecord,
  extendsConfig: configDatabaseRecord,
  properties: [
    { name: `username`, type: `varchar`, length: 20 },
    { name: `firstName`, type: `varchar`, length: 20 },
    { name: `lastName`, type: `varchar`, length: 20 },
    { name: `checkingBalance`, type: `decimal`, length: 17, decimals: 2 },
    { name: `permissions`, type: `Array`, arrayOf: { type: 'int' } },
    { name: `favoriteDay`, type: `date` }
  ],
  indexes: [
    { name: `username`, type: `BTREE`, columns: [ `username` ] }
  ]
};

/** Create the UserAccount object */
ezobjects.createClass(configUserAccount);

/** 
 * Create a new UserAccount called `userAccount`, initializing with 
 * plain object passed to constructor.
 */
const userAccount = new UserAccount({
  username: `richlowe`,
  firstName: `Rich`,
  lastName: `Lowe`,
  checkingBalance: 4.32,
  permissions: [1, 3, 5],
  favoriteDay: new Date(`01-01-2018`)
});

/** 
 * Test if `userAccount` is an instance of DatabaseRecord using
 * the included `instanceOf` helper function.
 */
console.log(ezobjects.instanceOf(userAccount, `DatabaseRecord`));

/** Let's use a self-executing async wrapper so we can await results */
(async () => {
  try {
    /** Create `user_accounts` table if it doesn`t already exist */
    await ezobjects.createTable(configUserAccount, db);

    /** Insert `userAccount` into the database */
    await userAccount.insert(db);
    
    /** Log `userAccount` (should have automatically incremented ID now) */
    console.log(userAccount);

    /** Capture ID of new record */
    const id = userAccount.id();
    
    /** Change the property values a bit */
    userAccount.checkingBalance(50.27);
    userAccount.firstName(`Richard`);
    userAccount.favoriteDay(new Date(`09-01-2019`));

    /** Update `userAccount` in the database */
    await userAccount.update(db);

    /** Log `userAccount` (should have `checkingBalance` of 50.27) */
    console.log(userAccount);

    /** Create another new UserAccount called `anotherUserAccount` */
    const anotherUserAccount = new UserAccount();
    
    /** 
     * Using the ID captured from the previous insert operation, load 
     * the record from database.
     */
    await anotherUserAccount.load(id, db);

    /** Log `anotherUserAccount` (should match last `userAccount`) */
    console.log(anotherUserAccount);

    /** Delete `anotherUserAccount` from the database */
    await anotherUserAccount.delete(db);
  } catch ( err ) {
    /** Cleanly log any errors */
    console.log(err.message);
  } finally {
    /** Close database connection */
    db.close();
  }
})();

Expected Output

true
UserAccount {
  _id: 1,
  _username: 'richlowe',
  _firstName: 'Rich',
  _lastName: 'Lowe',
  _checkingBalance: 4.32,
  _permissions: [ 1, 3, 5 ],
  _favoriteDay: 2018-01-01T06:00:00.000Z }
UserAccount {
  _id: 1,
  _username: 'richlowe',
  _firstName: 'Richard',
  _lastName: 'Lowe',
  _checkingBalance: 50.27,
  _permissions: [ 1, 3, 5 ],
  _favoriteDay: 2019-09-01T05:00:00.000Z }
UserAccount {
  _id: 1,
  _username: 'richlowe',
  _firstName: 'Richard',
  _lastName: 'Lowe',
  _checkingBalance: 50.27,
  _permissions: [ 1, 3, 5 ],
  _favoriteDay: 2019-09-01T05:00:00.000Z }

Basic EZ Object Method Signatures

These are the object method signatures even the most basic of EZ Objects will have:

new MyObject([data])

• Parameter: data - PlainObject - (optional)
• Description: Create a new MyObject object and initialize it using either defaults or any provided key/value pairs in the plain object data. Keys can either be equal to the name of a property, or they can be have an underscore before the name of a property, as would be the case if you were to JSON.stringify() and then JSON.parse() an EZ Object. This allows for easy transferability in cases where JSON is used as the transfer medium.

new MyObject([data])

• Parameter: data - string - (optional)
• Description: Create a new MyObject object and initialize it using either defaults or any provided key/value pairs in the JSON encoded string data. Keys can either be equal to the name of a property, or they can be have an underscore before the name of a property, as would be the case if you were to JSON.stringify() an EZ Object. This allows for easy transferability in cases where JSON is used as the transfer medium.

MyObject.init([data])

• Parameter: data - PlainObject
• Description: Initialize this object using either defaults or any provided key/value pairs in the plain object data. This is also the method used by the constructor.

In addition, each property you define will have a single method that is a getter and setter, and it will have the following signatures:

MyObject.myProperty()

• Returns: mixed
• Description: Get the value of the property.

MyObject.myProperty(value)

• Parameter: value - mixed
• Throws: TypeError if value is not of the correct javascript data type for myProperty
• Returns: this
• Description: Set the value of the property, throwing an error if the javascript data type does not match the configuration, this is how the strict typing is implemented. This signature returns this to allow for set call chaining.

MySQL EZ Object Method Signatures

These are the object method signatures that will additionally be provided if your configuration contains a tableName, meaning it's intended to be linked to a MySQL table:

MyObject.delete(db)

• Parameter: db - MySQLConnection
• Description: Delete the record in database db, table tableName, that has its id field equal to the id property of this object.

MyObject.insert(db)

• Parameter: db - MySQLConnection
• Description: Insert this object's property values into the database db, table tableName, and store the resulting insertId in the id property of this object.

MyObject.load(mysqlRow[, db])

• Parameter: mysqlRow RowDataPacket A MySQL RowDataPacket returned as part of a MySQL result set
• Parameter: db - MySQLConnection
• Description: Load any configured properties from key/value pairs in mysqlRow. You can optionally pass the database db if you need it to be provided as a third argument to any loadTransform methods on configured properties.

MyObject.load(obj[, db])

• Parameter: obj PlainObject
• Parameter: db - MySQLConnection
• Description: Load any configured properties from key/value pairs in obj. You can optionally pass the database db if you need it to be provided as a third argument to any loadTransform methods on configured properties.

MyObject.load(id, db)

• Parameter: id number The value of the id property of the record you wish to load
• Parameter: db - MySQLConnection
• Description: Load the record in database db, table tableName, that has its id field equal to provided id parameter.

MyObject.load(fieldValue, db)

• Parameter: fieldValue - mixed - The value of the otherSearchField property of the record you wish to load
• Parameter: db - MySQLConnection
• Description: Load the record in database db, table tableName, that has its otherSearchField field equal to provided fieldValue parameter. Here, the actual field name of otherSearchField is provided in the object configuration, see the configuration section below.

MyObject.load(url[, db])

• Parameter: url - string - The URL of a back-end that provides JSON data compatible with this object's initializer
• Parameter: db - MySQLConnection
• Description: Load any configured properties from the JSON-encoded key/value pairs obtained from url. You can optionally pass the database db if you need it to be provided as a third argument to any loadTransform methods on configured properties.
• Note: This signature is useful only when your classes are standalone browserify'd and requires you to implement a backend at url that will output the JSON. This signature also requires you have jQuery loaded prior to use.

MyObject.update(db)

• Parameter: db - MySQLConnection
• Description: Update the record in database db, table tableName, with its id field equal to the id property of this object, using this object's property values.

Module Exports

The EZ Objects module exports two functions and a MySQL class object:

ezobjects.createTable(objectConfig, db)

A function that creates a MySQL table corresponding to the configuration outlined in objectConfig, if it doesn't already exist

ezobjects.createClass(objectConfig)

A function that creates an ES6 class corresponding to the configuration outlined in objectConfig, with constructor, initializer, getters, setters, and also delete, insert, load, and update if tableName is configured

ezobjects.MySQLConnection(mysqlConfig)

A MySQL database connection class that wraps the standard mysql object and provides it with async/await functionality and transaction helpers

Configuration Specifications

See the following for how to configure your EZ Objects:

A basic MySQL object configuration can have the following:

• className - string - (required) Name of the class
• properties - Array - (optional) An array of property configurations that the object (and MySQL table, if applicable) should have corresponding properties for
• extends - mixed - (optional) The object that the new object should be extended from [required to extend object]
• extendsConfig - object - (optional) The EZ Object configuration for the object that is being extended from [required to extend object]
• indexes - Array - (optional) An array of MySQL index configurations that should be created in the MySQL table

A table-linked MySQL object configuration can also have the following:

• tableName - string - (optional) Provide if object should be linked with MySQL database table
• otherSearchField - string - (optional) The name of a unique property of type string that you want to be able to load with as an alternative to id

A basic property configuration can have the following:

• name - string - (required) Name of the property, must conform to both JavaScript and MySQL rules
• type - string - (optional) EZ Object type that the property must be equal to -- types can be bit, tinyint, smallint, mediumint, int, integer, bigint, real, double, float, decimal, numeric, date, time, timestamp, datetime, year, char, varchar, binary, varbinary, tinyblob, blob, mediumblob, longblob, tinytext, text, mediumtext, longtext, enum, set, boolean, function, any other valid object constructor name, or array where arrayOf is provided with information about the array element types. [either type or instanceOf is required]
• instanceOf - string - (optional) JavaScript class constructor name that the property must be an instance of [either type or instanceOf is required]
• default - mixed - (optional) Sets the default value for the property in the class object
• allowNull - boolean - (optional) Indicates the property can be null, default is that only plain objects and custom object types are nullable
• arrayOf - object - (required for type array) A plain object containing he EZ Object type or instanceOf of the elements of the array -- types can be bit, tinyint, smallint, mediumint, int, integer, bigint, real, double, float, decimal, numeric, date, time, timestamp, datetime, year, char, varchar, binary, varbinary, tinyblob, blob, mediumblob, longblob, tinytext, text, mediumtext, longtext, enum, set, boolean, function, or any other valid object constructor name (which can alternatively be used with instanceOf instead). [either type or instanceOf is required]
• setTransform(x, propertyConfig) - function - (optional) Function that transforms and returns the property value prior to setting. The handler for this transform will be passed the expected value type, if needed.

A MySQL property configuration can also have the following:

• length - number - (optional) MySQL data length for the property [required for some data types like VARCHAR, optional for others where it's used to determine displayed precision on SELECT'ed data types like FLOAT]
• decimals - number - (optional) Number of decimals that should be provided for certain data types when SELECT'ed from the MySQL table
• unique - boolean - (optional) Indicates the property is a UNIQUE KEY in the MySQL table
• unsigned - boolean - (optional) Indicates the property should be unsigned in the MySQL table
• zerofill - boolean - (optional) Indicates the property should be zero-filled in the MySQL table
• comment - string - (optional) Indicates the property should note the provided comment in the MySQL table
• characterSet - string - (optional) Indicates the property should use the provided charset in the MySQL table
• collate - string - (optional) Indicates the property should use the provided collation in the MySQL table
• autoIncrement - boolean - (optional) Indicates the property should be auto-incremented in the MySQL table
• saveTransform(x, propertyConfig) - function - (optional) Function that transforms and returns the property value prior to saving in the database
• loadTransform(x, propertyConfig, db) - function - (optional) Function that transforms and returns the property value after loading from the database. The handler for this transform will be passed the expected value type, if needed, along with the MySQL connection db if it was provided as the third argument of the object's load method.

A MySQL index configuration can have the following (for MySQL table association only):

• name - string - (required) Name of the index, can be arbitrary, but must be unique and not PRIMARY
• columns - Array - (required) An array of strings containing property names to be indexed
• type - string - (optional) Index type, can be BTREE or HASH, defaults to BTREE
• keyBlockSize - number - (optional) Indicates the index should use the provided key block size
• withParser - string - (optional) Indicates the index should use the provided parser
• visible - boolean - (optional) Indicates the index should be visible
• invisible - boolean - (optional) Indicates the index should be invisible

Default intiailizations for different JavaScript types

• bit - Buffer.from([])
• tinyint - 0
• smallint - 0
• mediumint - 0
• int - 0
• integer - 0
• bigint - 0
• real - 0
• double - 0
• float - 0
• decimal - 0
• numeric - 0
• date - new Date(0)
• time - 00:00:00
• timestamp - ``
• datetime - new Date(0)
• year - 0
• char - ``
• varchar - ``
• binary - Buffer.from([])
• varbinary - Buffer.from([])
• tinyblob - Buffer.from([])
• blob - Buffer.from([])
• mediumblob - Buffer.from([])
• longblob - Buffer.from([])
• tinytext - ``
• text - ``
• mediumtext - ``
• longtext - ``
• enum - ``
• set - new Set()
• boolean - false
• function - function () { }
• All array types - []
• All other types - null

Contributing

Please open an issue on the GitHub repository if you find any broken functionality or other bugs/errors. Feature requests will also be accepted, but are not guaranteed to be implemented.

License

MIT Licensed