MappifySQL: A MySQL ORM for Node.js and TypeScript
MappifySQL is a lightweight, easy-to-use Object-Relational Mapping (ORM) library for MySQL databases, designed for use with Node.js. It provides an intuitive, promise-based API for interacting with your MySQL database using JavaScript or TypeScript.
Features
- Object-Relational Mapping: Map your database tables to JavaScript or TypeScript objects for easier and more intuitive data manipulation.
- CRUD Operations: Easily perform Create, Read, Update, and Delete operations on your database.
- Transactions: Safely execute multiple database operations at once with transaction support.
- Relationships: Define relationships between your tables to easily fetch related data.
- Model Class: Define a model class for each table in your database to encapsulate database operations.
- Environment Variables: Use environment variables to store database connection details securely.
- TypeScript Support: Use MappifySQL with TypeScript for type-safe database interactions.
- SQL Injection Protection: Protect your application from SQL injection attacks with parameterized queries.
- Custom Queries: Execute custom SQL queries using the query method.
- Custom Functions: Create custom functions in your model classes to encapsulate complex queries or operations.
- Pagination: Implement pagination for large datasets with the limit and offset options.
Why MappifySQL?
MappifySQL aims to simplify working with MySQL databases in Node.js applications. By providing an object-oriented interface to your database, it allows you to write more readable and maintainable code. Whether you're building a small application or a large, complex system, MappifySQL has the features you need to get the job done.
Installation
To install MappifySQL, use npm:
npm install mappifysql
Getting Started
Importing the Library
import and use the library in your JavaScript or TypeScript file:
const mappifysql = require('mappifysql');
const Database = mappifysql.Database;
const MappifyModel = mappifysql.MappifyModel;
import mappifysql from 'mappifysql';
const Database = mappifysql.Database;
const MappifyModel = mappifysql.MappifyModel;
import the classes directly in your JavaScript or TypeScript file:
const { Database, MappifyModel } = require('mappifysql');
import { Database, MappifyModel } from 'mappifysql';
Here's a quick example to create a connection to a MySQL database using MappifySQL:
Connecting to a Database
To connect to a MySQL database using MappifySQL, you need to create a .env file in the root directory of your project and add the following environment variables:
DB_HOST=localhost
DB_USER=root
DB_PASSWORD=password
DB_NAME=mydatabase
DB_PORT=3306
Then, create a new JavaScript file (e.g., connection.js) and one of the following code snippets:
Create a single connection to the database
Create a new instance of the Database class and call the createConnection method to establish a single connection to the database
const { Database } = require('mappifysql');
const db = new Database();
db.createConnection().then(() => {
console.log('Database connected successfully');
}).catch((err) => {
console.error(err);
});
var connection = db.getConnection();
var query = db.getQuery();
module.exports = { connection, query };
** Using TypeScript **
import { Database } from 'mappifysql';
const db = new Database();
db.createConnection().then(() => {
console.log('Database connected successfully');
}).catch((err) => {
console.error(err);
});
var connection = db.getConnection();
var query = db.getQuery();
export { connection, query };
Create a pool of connections to the database
Call the createPool method to establish a pool of connections to the database. This is useful for managing multiple concurrent database queries, improving performance.
const { Database } = require('mappifysql');
const db = new Database();
db.createPool().then(() => {
console.log('Database connected successfully');
}).catch((err) => {
console.error(err);
});
var connection = db.getConnection();
var query = db.getQuery();
module.exports = { connection, query };
import { Database } from 'mappifysql';
const db = new Database();
db.createPool().then(() => {
console.log('Database connected successfully');
}).catch((err) => {
console.error(err);
});
var connection = db.getConnection();
var query = db.getQuery();
export { connection, query };
Methods available in the connection object:
Method | Description | Parameters | Supported by |
---|
beginTransaction | Begins a transaction. | callback?: (err: any) => void | createConnection |
commit | Commits the current transaction. | callback?: (err: any) => void | createConnection |
rollback | Rolls back the current transaction. | callback?: (err: any) => void | createConnection |
query | Sends a SQL query to the database. | sql: string , values?: any , callback?: (error: any, results: any, fields: any) => void | createConnection , createPool |
end | Ends the connection. | callback?: (err: any) => void | createConnection , createPool |
destroy | Destroys the connection. | None | createConnection |
pause | Pauses the connection. | None | createConnection |
resume | Resumes the connection. | None | createConnection |
escape | Escapes a value for SQL. | value: any | createConnection , createPool |
escapeId | Escapes an identifier for SQL. | value: any | createConnection , createPool |
format | Formats a SQL query string. | sql: string , values?: any | createConnection , createPool |
ping | Pings the server. | callback?: (err: any) => void | createConnection , createPool |
changeUser | Changes the user for the current connection. | options: any , callback?: (err: any) => void | createConnection |
Example:
const { connection } = require('./connection');
connection.query('SELECT * FROM users', (err, results, fields) => {
if (err) {
throw err;
}
console.log('Fetched records:', results);
});
** Using TypeScript **
import { connection } from './connection';
connection.query('SELECT * FROM users', (err, results, fields) => {
if (err) {
throw err;
}
console.log('Fetched records:', results);
});
Using the Model Class
MappifySQL provides a Model class that allows you to define a JavaScript class that represents a table in your database. This class provides methods for performing CRUD operations on the table.
Here's an example of how to define a model class:
create a new file (e.g., Users.js) and add the following code:
const { MappifyModel } = require('mappifysql');
class User extends MappifyModel {
}
module.exports = User;
** Using TypeScript **
import { MappifyModel } from 'mappifysql';
interface UserAttributes {
first_name: string;
last_name: string;
email: string;
password: string;
}
class User extends MappifyModel {
id: number;
first_name: string;
last_name: string;
email: string;
password: string;
constructor(data: UserAttributes) {
super();
this.first_name = data.first_name;
this.last_name = data.last_name;
this.email = data.email;
this.password = data.password;
}
}
export default User;
Note: By default, the Model class uses the table name derived from the class name and assumes that the table name in the database is the plural form of the class name. If your table name is different, you can override the tableName property in your model class.
const { MappifyModel } = require('mappifysql');
class User extends MappifyModel {
static get tableName() {
return 'my_user_table_name';
}
}
module.exports = User;
** Using TypeScript **
import { MappifyModel } from 'mappifysql';
class User extends MappifyModel {
static get tableName() {
return 'my_user_table_name';
}
}
export default User;
Performing CRUD Operations
Once you have defined a model, you can use it to perform CRUD operations on the corresponding table.
const User = require('path/to/user.js')
let fetchAll = async () => {
User.findAll().then((results) => {
console.log('Fetched records:', results);
}).catch((err) => {
console.error(err);
});
};
let addData = async () => {
let newUser = new User({ name: 'John Doe', email: 'john.doe@example.com' });
User.save().then(() => {
console.log('New record inserted successfully');
}).catch((err) => {
console.error(err);
});
};
let updateData = async () => {
User.findById(1).then((record) => {
record.setProperties({ name: 'Jane Doe', email: 'jane.doe@example.com' });
record.update().then(() => {
console.log('Record updated successfully');
}).catch((err) => {
console.error(err);
});
}).catch((err) => {
console.error(err);
});
};
let deleteData = async () => {
User.findByIdAndDelete(1).then(() => {
console.log('Record deleted successfully');
}).catch((err) => {
console.error(err);
});
};
** Import in TypeScript **
import User from 'path/to/user.ts'
Model Class
This file contains a base model class with methods for interacting with a database. Each method corresponds to a common database operation.
Methods
MappifySQL save Method
This method inserts a new record into the database. It uses the properties of the instance to determine the column names and values.
Example:
let user = new User({ name: 'John Doe', email: 'joh.doe@example.com' });
user.save().then(() => {
console.log('New record inserted successfully');
}).catch((err) => {
console.error(err);
});
MappifySQL Update Method
This method updates the record associated with the instance in the database. It uses the properties of the instance to determine the column names and values.
Example:
User.findById(1).then((record) => {
record.setProperties({ name: 'Jane Doe', email: 'janedoe@example.com' });
record.update().then(() => {
console.log('Record updated successfully');
}).catch((err) => {
console.error(err);
});
}).catch((err) => {
console.error(err);
});
MappifySQL delete Method
This method deletes the record associated with the instance from the database.
Example:
User.findById(1).then((record) => {
record.delete().then(() => {
console.log('Record deleted successfully');
}).catch((err) => {
console.error(err);
});
}).catch((err) => {
console.error(err);
});
MappifySQL fetch Method
This method fetches all the records associated with the instance from the database.
Example:
User.fetch().then((records) => {
console.log('Fetched records:', records);
}).catch((err) => {
console.error(err);
});
MappifySQL findOne Method
This method finds one record in the database that matches the specified conditions. The parameter is an object that can contain the following properties:
where
: An object specifying the conditions for the query. - required exclude
: An array of column names to exclude from the result.attributes
: An array of column names to include in the result.
const user = await User.findOne({ where: { email: 'user@example.com' } });
const product = await Product.findOne({ where: { id: 1 }, exclude: ['description'] });
const admin = await User.findOne({ where: { role: 'admin' }, attributes: ['id', 'name', 'email'] });
const user = await User.findOne({ where: { age: { eq: 18 } } });
const user = await User.findOne({ where: { age: { gt: 17 } } });
const user = await User.findOne({ where: { age: { lt: 10 } } });
const user = await User.findOne({ where: { age: { gte: 18 } } });
const user = await User.findOne({ where: { age: { lte: 10 } } });
const user = await User.findOne({ where: { age: { ne: 18 } } });
const user = await User.findOne({ where: { age: { gt: 10, lt: 20 } } });
const product = await Product.findOne({ where: { name: { like: '%apple%' } } });
const product = await Product.findOne({ where: { name: { notLike: '%apple%' } } });
const product = await Product.findOne({ where: { category: { in: ['electronics', 'clothing'] } } });
const product = await Product.findOne({ where: { category: { notIn: ['electronics', 'clothing'] } } });
const product = await Product.findOne({ where: { price: { between: [10, 20] } } });
const product = await Product.findOne({ where: { price: { notBetween: [10, 20] } } });
const product = await Product.findOne({ where: { description: { isNull: true } } });
const product = await Product.findOne({ where: { description: { isNotNull: true } } });
const product = await Product.findOne({ where: { category: 'electronics', price: { gt: 10 } } });
const product = await Product.findOne({ where: { and: [{ category: 'electronics' }, { price: { gt: 10 } }] } });
const product = await Product.findOne({ where: { name: { like: '%apple%' }, and: [{ category: 'electronics' }, { price: { gt: 10 } }] } });
const product = await Product.findOne({ where: { or: [{ category: 'electronics' }, { price: { gt: 10 } }] } });
const product = await Product.findOne({ where: { name: { like: '%apple%' }, or: [{ category: 'electronics' }, { price: { gt: 10 } }] } });
const product = await Product.findOne({ where: { not: { category: 'electronics' } } });
const product = await Product.findOne({attributes: ['id', 'name', 'price'], where: { not: { category: 'electronics' } }});
Here is a table for the LIKE operators in the where clause:
Operator | Description |
---|
%apple% | Finds any values that have "apple" in any position |
apple% | Finds any values that start with "apple" |
%apple | Finds any values that end with "apple" |
_pple | Finds any values that have "pple" in the second position |
a%e | Finds any values that start with "a" and end with "e" |
a%o | Finds any values that start with "a" and ends with "o" |
a__% | Finds any values that start with "a" and are at least 3 characters in length |
a_% | Finds any values that start with "a" and are at least 2 characters in length |
_r% | Finds any values that have "r" in the second position |
MappifySQL findById Method
This method finds one record in the database with the specified id.
Example:
User.findById(1).then((record) => {
console.log('Fetched record:', record);
}).catch((err) => {
console.error(err);
});
MappifySQL findAll Method
This method finds all records in the database that match the specified conditions. The options
parameter is an object that can contain the following properties:
where
: An object specifying the conditions for the query.exclude
: An array of column names to exclude from the result.attributes
:An array of column names to include in the result. Default is ['*'] which selects alllimit
: The maximum number of records to return.offset
: The number of records to skip before starting to return records.order
: A string specifying the order in which to return the records.group
: A string specifying the column to group the records by. (column_name ASC/DESC);
Example:
const products = await Product.findAll();
const products = await Product.findAll(attributes: ['id', 'name', 'price']);
const products = await Product.findAll(exclude: ['description']);
const products = await Product.findAll({ limit: 10 });
const products = await Product.findAll({ limit: 10, offset: 2 });
const products = await Product.findAll({ where: { category: 'electronics' } });
const products = await Product.findAll({ where: { category: 'electronics' }, exclude: ['description'] });
const products = await Product.findAll({ attributes: ['category', 'COUNT(*) AS total'], group: 'category' });
const products = await Product.findAll({ group: 'category', order: 'price DESC' });
const products = await Product.findAll({ where: { price: { eq: 1000 } } });
const products = await Product.findAll({ where: { price: { gt: 1000 } } });
const products = await Product.findAll({ where: { price: { lt: 1000 } } });
const products = await Product.findAll({ where: { price: { gte: 1000 } } });
const products = await Product.findAll({ where: { price: { lte: 1000 } } });
const products = await Product.findAll({ where: { price: { ne: 1000 } } });
const products = await Product.findAll({ where: { price: { gt: 500, lt: 1000 } } });
const products = await Product.findAll({ where: { name: { like: '%apple%' } } });
const products = await Product.findAll({ where: { name: { notLike: '%apple%' } } });
const products = await Product.findAll({ where: { category: { in: ['electronics', 'clothing'] } } });
const products = await Product.findAll({ where: { category: { notIn: ['electronics', 'clothing'] } } });
const products = await Product.findAll({ where: { price: { between: [500, 1000] } } });
const products = await Product.findAll({ where: { price: { notBetween: [500, 1000] } } });
const products = await Product.findAll({ where: { description: { isNull: true } } });
const users = await User.findAll({ where: { is_subscribed: { isNotNull: true } } });
const products = await Product.findAll({ where: { category: 'electronics', price: { gt: 500 } } });
const products = await Product.findAll({ where: { and: [{ category: 'electronics' }, { price: { gt: 500 } }] }});
const products = await Product.findAll({ where: { name: { like: '%apple%' }, and: [{ category: 'electronics' }, { price: { gt: 500 } }] }});
const products = await Product.findAll({ where: { or: [{ category: 'electronics' }, { price: { gt: 500 } }] } });
const products = await Product.findAll({ where: { name: { like: '%apple%' }, or: [{ category: 'electronics' }, { price: { gt: 500 } }] }});
const products = await Product.findAll({ where: { not: { category: 'electronics' } } });
const products = await Product.findAll({attributes: ['id', 'name', 'price'], where: { not: { category: 'electronics' } }});
Operations
Operation | Description |
---|
eq | Equal to = |
gt | Greater than > |
lt | Less than < |
gte | Greater than or equal to >= |
lte | Less than or equal to <= |
ne | Not equal to <> |
like | Like %value% |
notLike | Not Like %value% |
in | In ('value1', 'value2') |
notIn | Not In ('value1', 'value2') |
between | Between value1 AND value2 |
notBetween | Not Between value1 AND value2 |
isNull | Is Null |
isNotNull | Is Not Null |
and | Logical AND |
or | Logical OR |
not | Logical NOT |
MappifySQL findOrCreate Method
This method finds one record in the database that matches the specified conditions, or creates a new record if no matching record is found. This function returns a object with two properties: record
and created
. The record
property contains the record found or created, and the created
property is a boolean value indicating whether the record was created or not. This function can be useful implementing a third-party login system where you want to find a user by their email or create a new user if they don't exist.
Parameters:
There are two parameters for this method:
-
options
: This is the first parameter and is an object that specifies the conditions for the record to find. It can contain the following properties:
where
: An object specifying the conditions for the query. required exclude
: An array of column names to exclude from the result.attributes
: An array of column names to include in the result.
-
defaults
: This is the second parameter and is an object that specifies the values to use when creating a new record. If a record is found, these values are ignored.
Example:
let { record, created } = await User.findOrCreate({ where: { email: 'user@example.com' } }, { name: 'John Doe', picture: 'default.jpg', role: 'user' });
if (created) {
console.log('New user created:', record);
} else {
console.log('User found:', record);
}
let { record, created } = await User.findOrCreate({ where: { or: [{ email: 'user@example.com' }, { username: 'user' }] } }, { name: 'John Doe', picture: 'default.jpg', role: 'user' });
MappifySQL findByIdAndDelete Method
The findByIdAndDelete
method finds a single record in the database that matches the specified id
and deletes it. The parameter is the id of the record to delete.
Example:
User.findByIdAndDelete(1).then(() => {
console.log('Record deleted successfully');
}).catch((err) => {
console.error(err);
});
MappifySQL findOneAndDelete Method
This method finds one record in the database that matches the specified conditions and deletes it.
Parameters:
There are two parameters for this method:
options
: This is the first parameter and is an object that specifies the conditions for the record to find. It can contain the following properties:
where
: An object specifying the conditions for the query. required
Example:
User.findOneAndDelete({ where: { email: 'user@example.com' } }).then(() => {
console.log('Record deleted successfully');
}).catch((err) => {
console.error(err);
});
MappifySQL findOneAndUpdate Method
This method finds one record in the database that matches the specified conditions and updates it.
Parameters:
There are two parameters for this method:
-
options
: This is the first parameter and is an object that specifies the conditions for the record to find. It can contain the following properties:
where
: An object specifying the conditions for the query. required exclude
: An array of column names to exclude from the result after the update.attributes
: An array of column names to include in the result after the update.
-
data
: This is the second parameter and is an object that specifies the values to update.
Example:
User.findOneAndUpdate({ where: { email: 'user@example.com' } }, { name: 'Jane Doe', picture: 'profile.jpg' }).then(() => {
console.log('Record updated successfully');
}).catch((err) => {
console.error(err);
});
MappifySQL findByIdAndUpdate Method`
This method finds one record in the database with the specified id and updates it.
Parameters:
There are two parameters for this method:
id
: This is the first parameter and is the id of the record to update.data
: This is the second parameter and is an object that specifies the values to update.
Example:
User.findByIdAndUpdate(1, { name: 'Jane Doe', picture: 'profile.jpg' }).then(() => {
console.log('Record updated successfully');
}).catch((err) => {
console.error(err);
});
Custom Queries
You can execute custom SQL queries using the query method provided by MappifySQL. This method allows you to execute any SQL query and returns a promise that resolves with the result of the query.
Example:
const { connection, query } = require('./connection');
let customQuery = async () => {
try {
let results = await query('SELECT * FROM users WHERE role = ?', ['admin']);
console.log('Fetched records:', results);
} catch (err) {
console.error(err);
}
};
let customQuery = async () => {
try {
let results = await connection.query('SELECT * FROM products WHERE name LIKE ?', ['%apple%'], (err, results, fields) => {
if (err) {
throw err;
}
console.log('Fetched records:', results);
});
} catch (err) {
console.error(err);
}
};
Note: The query method returns a promise that resolves with the result of the query. You can use async/await to handle the asynchronous nature of the database operations.
You can implement pagination for large datasets using the limit and offset options in the findAll method. The limit option specifies the maximum number of records to return, and the offset option specifies the number of records i.e. the page number you are on.
Example:
By passing the offset dynamically using query parameters, you can fetch the next set of records for each page.
var page = req.query.page;
const products = await Product.findAll({ limit: 10 , offset: page });
Creating a custom function for a model class to perform a database operation
You can create a custom function for a model class to perform a database operation. This function can be used to encapsulate complex queries or operations that are specific to the model.
Example:
const { MappifyModel } = require('mappifysql');
class Product extends MappifyModel {
static async findElectronics() {
try {
let sql = `SELECT * FROM ${this.tableName} WHERE category = ?`;
let results = await this.query(sql, ['electronics']);
if (results.length > 0) {
return results.map(result => new this(result));
}
return [];
} catch (err) {
throw err;
}
}
static async findElectronics() {
try {
let results = await this.findAll(attributes: ['id', 'name', 'price'], and: [{ category: 'electronics' }, { price: { between: [500, 1000] } }]);
return results;
} catch (err) {
throw err;
}
}
}
module.exports = User;
Usage:
const Product = require('path/to/product.js');
Product.findElectronics().then((products) => {
console.log('Electronics products:', products);
}).catch((err) => {
console.error(err);
});
** Using TypeScript **
const { MappifyModel } = require('mappifysql');
interface ProductAttributes {
name: string;
price: number;
category: string;
}
class Product extends MappifyModel {
id: number;
name: string;
price: number;
category: string;
constructor(data: ProductAttributes) {
super();
this.name = data.name;
this.price = data.price;
this.category = data.category;
}
static async findElectronics() {
try {
let results = await MappifyModel.findAll(attributes: ['id', 'name', 'price'], and: [{ category: 'electronics' }, { price: { between: [500, 1000] } }]);
return results;
} catch (err) {
throw err;
}
}
}
export default Product;
Usage:
import Product from 'path/to/product.ts';
Product.findElectronics().then((products) => {
console.log('Electronics products:', products);
}).catch((err) => {
console.error(err);
});
MappifySQL Transactions
MappifySQL supports transactions, allowing you to execute multiple database operations as a single unit of work. This ensures that all operations are completed successfully or none of them are.
Note: Transactions are only supported when created a single connection using the createConnection method. Transactions are not supported in pool because a pool consists of multiple connections to the database.
const { connection, query } = require('./connection');
let performTransaction = async () => {
try {
connection.beginTransaction();
var user = await query('INSERT INTO users SET ?', { name: 'John Doe'});
await query('INSERT INTO addresses SET ?', { user_id: user.insertId, address: '123 Main St' });
connection.commit();
console.log('Transaction completed successfully');
} catch (err) {
connection.rollback();
console.error(err);
}
};
let performTransaction = async () => {
try {
connection.beginTransaction();
let user = new User({ name: 'John Doe' });
await user.save();
let address = new Address({ user_id: user.id, address: '123 Main St' });
await address.save();
connection.commit();
console.log('Transaction completed successfully');
} catch (err) {
await connection.rollback();
console.error(err);
}
};
Relationships
MappifySQL allows you to define relationships between your tables, making it easier to fetch related data.
This table provides a quick reference for the methods available in defining relationships between models.
Method | Description | Parameters | Example |
---|
associations | Defines the associations that a model has with other models. This method is meant to be overridden in subclasses. | None | associations() { this.belongsTo(User, { as: 'user', key: 'id', foreignKey: 'user_id' }); } |
hasOne | Defines a one-to-one relationship between two models. | relatedModel , options | this.hasOne(ShippingAddress, { as: 'shippingAddress', foreignKey: 'order_id' }); |
belongsTo | Defines a one-to-one relationship where the model belongs to another model. | relatedModel , options | this.belongsTo(Order, { as: 'order', key: 'id', foreignKey: 'order_id' }); |
hasMany | Defines a one-to-many relationship where the model has many instances of another model. | relatedModel , options | this.hasMany(User, { as: 'user', foreignKey: 'post_id' }); |
belongsToMany | Defines a many-to-many relationship between two models. | relatedModel , options | this.belongsToMany(Course, { as: 'courses', through: Enrollment, key: 'id', foreignKey: 'student_id', otherKey: 'course_id' }); |
populate | Fetches the related data for a given relation. | relation , options (optional) | await post.populate('user'); |
This table provides a quick reference for the options available in defining relationships between models.
Method | Key | Description |
---|
hasOne | as | The alias for the association. |
| foreignKey | The foreign key in this model. |
belongsTo | as | The alias for the association. |
| key | The primary key in the related model. |
| foreignKey | The foreign key in this model. |
hasMany | as | The alias for the association. |
| foreignKey | The foreign key in the related model. |
belongsToMany | as | The alias for the association. |
| through | The "join" table model that connects the two models. |
| key | The primary key in the related model. |
| foreignKey | The foreign key in through model for this model. |
| otherKey | The foreign key in through model for the related model. |
populate | attributes | The columns to include in the result. |
| exclude | The columns to exclude from the result. |
Please note that attributes
and exclude
keys in the populate
method are optional.
Defining Relationships
One-to-One Relationship
In a one-to-one relationship, each record in one table is associated with exactly one record in another table. For example, each order has exactly one shipping address, and each shipping address belongs to exactly one order.
const { MappifyModel } = require('mappifysql');
const ShippingAddress = require('path/to/ShippingAddress');
class Order extends MappifyModel {
associations() {
this.hasOne(ShippingAddress, {
as: 'shippingAddress',
foreignKey: 'order_id'
});
}
}
module.exports = Order;
Usage:
const Order = require('path/to/Order');
Order.findByOne({ where: { id: 1 }}).then((order) => {
order.populate('shippingAddress', {exclude: ['created_at', 'updated_at']}).then((order) => {
console.log('Order with shipping address:', order);
});
}).catch((err) => {
console.error(err);
});
Order.findAll().then((orders) => {
orders.forEach(async (order) => {
await order.populate('shippingAddress', {exclude: ['created_at', 'updated_at']});
console.log('Order with shipping address:', order);
});
}).catch((err) => {
console.error(err);
});
** Using TypeScript **
import { MappifyModel } from 'mappifysql';
import Order from 'path/to/Order';
interface ShippingAddressAttributes {
id: number;
address: string;
city: string;
state: string;
}
class ShippingAddress extends MappifyModel {
id: number;
address: string;
city: string;
constructor(data: ShippingAddressAttributes) {
super();
this.id = data.id;
this.address = data.address;
this.city = data.city;
}
associations() {
this.belongsTo(Order, {
as: 'order',
key: 'id'
foreignKey: 'order_id'
});
}
}
export default ShippingAddress;
Usage:
import ShippingAddress from 'path/to/ShippingAddress';
ShippingAddress.findByOne({ where: { id: 1 }}).then((shippingAddress) => {
shippingAddress.populate('order', {attributes: ['id', 'total']}).then((shippingAddress) => {
console.log('Shipping address with order:', shippingAddress);
});
}).catch((err) => {
console.error(err);
});
One-to-Many Relationship
In a one-to-many relationship, each record in one table is associated with one or more records in another table. For example, each user can have multiple orders, but each order belongs to exactly one user.
const { MappifyModel } = require('mappifysql');
const Order = require('path/to/Order');
class User extends MappifyModel {
associations() {
this.hasMany(Order, {
as: 'orders',
foreignKey: 'user_id'
});
}
}
module.exports = User;
Usage:
const User = require('path/to/User');
let fetchUserOrders = async () => {
var user = await User.findOne({ where: { id: 1 } });
await user.populate('orders', { exclude: ['created_at', 'updated_at'] });
console.log('User with orders:', user);
};
fetchUserOrders();
** Using TypeScript **
import { MappifyModel } from 'mappifysql';
import Order from 'path/to/Order';
interface OrderAttributes {
id: number;
total: number;
}
class Order extends MappifyModel {
id: number;
total: number;
constructor(data: OrderAttributes) {
super();
this.id = data.id;
this.total = data.total;
}
associations() {
this.belongsTo(User, {
as: 'user',
key: 'id'
foreignKey: 'user_id'
});
}
}
export default User;
Usage:
import Order from 'path/to/Order';
let fetchOrderUser = async () => {
var order = await Order.findOne({ where: { id: 1 } });
await order.populate('user', {attributes: ['id', 'name']});
console.log('Order with user:', order);
};
fetchOrderUser();
Many-to-Many Relationship
In a many-to-many relationship, each record in one table is associated with one or more records in another table, and vice versa. For example, each product can belong to multiple categories, and each category can have multiple products.
const { MappifyModel } = require('mappifysql');
const Category = require('path/to/Category');
const ProductCategory = require('path/to/ProductCategory');
class Product extends MappifyModel {
associations() {
this.belongsToMany(Category, {
as: 'categories',
through: ProductCategory,
key: 'id',
foreignKey: 'product_id',
otherKey: 'category_id'
});
}
}
module.exports = Product;
Usage:
const Product = require('path/to/Product');
Product.findOne({ where: { id: 1 }}).then((product) => {
product.populate('categories', { exclude: ['created_at', 'updated_at'] }).then((product) => {
console.log('Product with categories:', product);
});
}).catch((err) => {
console.error(err);
});
** Using TypeScript **
import { MappifyModel } from 'mappifysql';
import Product from 'path/to/Product';
import ProductCategory from 'path/to/ProductCategory';
interface CategoryAttributes {
id: number;
name: string;
}
class Category extends MappifyModel {
id: number;
name: string;
constructor(data: CategoryAttributes) {
super();
this.id = data.id;
this.name = data.name;
}
associations() {
this.belongsToMany(Product, {
as: 'products',
through: ProductCategory,
key: 'id',
foreignKey: 'category_id',
otherKey: 'product_id'
});
}
}
export default Category;
Usage:
import Category from 'path/to/Category';
Category.findOne({ where: { id: 1 }}).then((category) => {
category.populate('products', {attributes: ['id', 'name', 'price']}).then((category) => {
console.log('Category with products:', category);
});
}).catch((err) => {
console.error(err);
});
Note: The model classes can contain many relationships, and you can define as many relationships as needed for your application. Also, if a model has multiple relationships, you can populate them individually for each relationship.
Example:
const { MappifyModel } = require('mappifysql');
const Student = require('path/to/studentmodel');
const Course = require('path/to/coursemodel');
class Enrollment extends MappifyModel {
associations() {
this.belongsTo(Student, {
as: 'student',
key: 'id',
foreignKey: 'student_id'
});
this.belongsTo(Course, {
as: 'course',
key: 'id',
foreignKey: 'course_id'
});
}
}
module.exports = Enrollment;
Usage:
const Enrollment = require('path/to/Enrollment');
Enrollment.findOne({ where: { id: 1 }}).then((enrollment) => {
enrollment.populate('student', {attributes: ['id', 'name']}).then(() => {
}).then(() => {
enrollment.populate('course', {attributes: ['id', 'name']}).then(() => {
console.log('Enrollment with student and course:', enrollment);
});
});
}).catch((err) => {
console.error(err);
});
** Using TypeScript **
import { MappifyModel } from 'mappifysql';
import Student from 'path/to/studentmodel';
import Course from 'path/to/coursemodel';
interface EnrollmentAttributes {
id: number;
student_id: number;
course_id: number;
}
class Enrollment extends MappifyModel {
id: number;
student_id: number;
course_id: number;
constructor(data: EnrollmentAttributes) {
super();
this.id = data.id;
this.student_id = data.student_id;
this.course_id = data.course_id;
}
associations() {
this.belongsTo(Student, {
as: 'student',
key: 'id',
foreignKey: 'student_id'
});
this.belongsTo(Course, {
as: 'course',
key: 'id',
foreignKey: 'course_id'
});
}
}
export default Enrollment;
Usage:
import Enrollment from 'path/to/Enrollment
let enroll = async () => {
var enrollment = await Enrollment.findOne({ where: { id: 1 } });
await enrollment.populate('student', {attributes: ['id', 'name']});
await enrollment.populate('course', {attributes: ['id', 'name']});
console.log('Enrollment with student and course:', enrollment);
};
enroll();
Issues
If you encounter any issues or have any questions, please feel free to open an issue on the GitHub repository. We are always happy to help and improve the library.
License
This project is licensed under the MIT License - see the LICENSE file for details.
References