Mongoose

Tags: #◇Web Development #◇CCAPDEV #◇Mongoose #◇Code Snippets #◇M5

◇Overview

Extracted notes for Mongoose covering both theoretical and practical elements.

◇Key Definitions

What is Mongoose? Mongoose provides a straightforward, schema-based solution to model your application data It manages relationships between data It provides schema validation It translates objects in code to MongoDB document representation It is an Object Data Modelling (ODM) library for MongoDB and Nodejs It includes built-in typecasting, schema validation, query building, and many more It is built on top of the MongoDB Nodejs driver, ‘mongodb’ on npm
Installing Mongoose Search for mongoose in the npm repository and follow the installation instructions Navigate to your project directory Run the command npm init Run the command npm install mongoose
Mongoose Terminologies There are a couple of Mongoose terminologies that needs defining, starting with schemas Schemas define the structure of the document MongoDB is a schema-less database management system It can be quite flexible However, documents can look very different from one another even if they’re in the same collection https://mongoosejs.com/docs/guide.html
Mongoose Terminologies Although MongoDB is schema-less, a Mongoose schema can define the document structure to be enforced (which is useful for validation) Mongoose still works on the MongoDB DBMS However, Mongoose allows for strongly-typed documents/collections to exist This is a big help with validation, since you’d normally want to check strings against strings, numbers against numbers, etc. https://mongoosejs.com/docs/guide.html
Mongoose Terminologies Another concept in Mongoose is the model A mongoose model is a constructor that lets you create instances of a document using the defined schema A model is a rough equivalent of a collection in the underlying MongoDB database. Models are also responsible for the CRUD operations performed unto the specified collection on the database https://mongoosejs.com/docs/models.html

◇Code Implementation

Getting Started
Similar to the mongodb nodejs driver way, pass the URI and connection options, if needed
mongoose.connect(uri, options)
You can specify the database in either the uri or in the options, through the field dbName
This function call returns a promise, which you can the attach callback statements using .then
If you are working with multiple databases, you can use mongoose.createConnection to create additional connections
This function call returns a connection object which can be used to access the specified database
https://mongoosejs.com/docs/connections.html

Getting Started
mongoose.connect("mongodb://localhost:27017/myProject")
or
mongoose.connect("mongodb://localhost:27017/“, {dbName: 'myProject’});
Other options can be found here:
https://mongoosejs.com/docs/connections.html#options
https://mongoosejs.com/docs/connections.html

// A Sample Schema
const userSchema = new mongoose.Schema({
  name: {
    first: String,
    last: { type: String, trim: true }
  },
  age: { 
    type: Number,
    min: 0
  }
});

 Text Editor
 models/user.js 
https://mongoosejs.com/docs/guide.html

 models/user.js 
// A Sample Schema
const userSchema = new mongoose.Schema({
  name: {
    first: String,
    last: { type: String, trim: true }
  },
  age: { 
    type: Number,
    min: 0
  }
});
// A Sample Model
const User = mongoose.model('user', userSchema);

 Text Editor
 models/user.js

const UserSchema = new mongoose.Schema({
    fName: String,
    idNum: Number,
    pw: {
        type: String,
        required: true
    }
});

 Text Editor
models/user.js

◇Syntax Breakdown

Ensure correct syntax for Mongoose Pay attention to specific functions and declarations.

◇Complexity Analysis

Time Complexity: O(1) for typical operations unless looping. Space Complexity: O(1) generally.

◇References & Navigation

• Previous Topic: ◇MongoDB
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• Related Notes: ◇Client Server Architecture