Be a Mongoose Master

What is mongoDB ?

MongoDB is an NO-SQL Database, Which store JSON like documents.
Mongo Stores data like BSON Format.
No-SQL databases break from relational models, ideal for managing vast data.
MongoDB stands out for it's scalability, flexibility and performance trusted by giants like Facebook , Google, EBay.
MongoDB is Developed By MongoDB Inc

Why we use `MongoDB` ?

Highly Scalable, High-performance and Open-source.
Document Oriented Database
Cost Effective Solutions.
Rich Ecosystem of Tools, Documents and community.

What is the different between MongoDB & Relational Database.

Features	MongoDB	Relational Database
Data Model	Document Oriented	Relational
Schema	Flexible	RigId
Scalability	Horizontally & Vertically	Vertically
Performance	Optimized Structure or UnStructure Data	On Structured Dat

Main Difference MongDB and Relational Database:

graph TD;
 subgraph A[RDBMS]
    subgraph B[Table]
       subgraph  C[Rows]
            D[Columns]
         end
      end
  end

graph TD;
 subgraph A[NO-SQL]
    subgraph B[Collection]
       subgraph  C[Document]
            D[Fields]
         end
      end
  end

MongoDB Features:

JSON Like Documents (BSON).
Indexing
Aggregation Framework.
Security Features
Free Atlas Database
MongoDB Compass GUI

Setup MongoDB in Computer :

Download MongoDB for windows.
Install mongodb for windows
When we install mongoDB with Mongo Compass automatically installed.
MongoDB Shell :
- Download mongoDB shell msi version
- install It.
- Then go your local drive. My local drive is C drive.
- Copy this bin folder path:
```
   C:\Program Files\MongoDB\Server\7.0\bin
```
- Search on window : for Environment Variable and setup then click on path.
- Add a new path
- the save it.
Use mongo shell or mongosh :
- run this command to check mongosh version:
```
   mongod --version
```
- to use mongoDB shell on CMD the command :
```
mongosh;
```
- the run any command of mongodb to access database.

Install `NoSQLBootstar` or `Studio 3T` for graphical User Interface of MongoDB.

This help us to data visualization.
Install any of them and create a connection.

MongoDB Shell `Function` & `Operation` :

Function	for use	example
`show dbs`	show all database	`show dbs`
`use database`	create new or switch	`use newDatabaseName`
`db.createCollection("name")`	create new collection	`db.createCollection('test')`
`db.getCollection("collectionName")`	get Collection	`db.getCollection('test')`
`db.collectionName`	get Collection another way	`db.test`
`db.collectionName.insertOne(object)`	insert one documents	`db.test.insertOne({name: "next Level"})`
`db.collectionName.insertMany([object, object])`	insert array of data	`db.test.insertMany([{name: "next Level"}, {name: "Complete web "}])`
`db.collectionName.find(query)`	find data from collection by query	`db.test.find({name: "Complete Web"})`
`db.collectionName.findOne(query)`	find the first Occurrence	`db.test.findOne({name: "Complete Web"})`

Projection or `Field Filtering` with MongoDB:

We can projectfield by using project() or by passing second parameter of find({}, field filter object) and findOne(query, field filter object)

By passing second parameter of `find() or findOne()`:

1 means keep the property 0 means remove the property.
syntax: here

db.collectionName.find(
   {},
   { _id: 0, propertyName: 1, propertyName: 1, propertyName: 1 }
);

Example:

// inclusion
db.test.find({ company: "Flashspan" }, { name: 1, email: 1, gender: 1 });

// exclusion:
db.test.find(
   { company: "Flashspan" },
   { name: 0, email: 0, gender: 0, _id: 0 }
);

`projection()` or `project()` method:

projection() and project() aren't work for findOne() method.
we can pass 1 or 0 as property value.
1 mean get the property
0 means remove the property
syntax :

// inclusion
db.test.find({}).project({ name: 1, email: 1 });
db.test.find({ age: 12 }).projection({ name: 1, email: 1, age: 1 });

// exclusion:
db.test.find().project({ _id: 0 });
db.test.find().projection({ _id: 0 });

`Operator` In MongoDB:-

Thumb Rule : যখন কোনো Operator আসবে তখন একটা সেকেন্ড ব্রেকেট { } আনতে হবে।

Comparison Operator :

Operator	why use	syntax	example
`$eq`	to check equal value	`{<field>: {$eq: value }}`	`db.test.find({age: {$eq: 12}})`
`$ne`	to check not equal value	`{<field>: {$ne: value }}`	`db.test.find({age: {$ne: 12}})`
`$gt`	get the larger value	`{<field>: {$gt: value }}`	`db.test.find({age: {$gt: 12}})`
`$lt`	get the smaller value	`{<field>: {$lt: value }}`	`db.test.find({age: {$lt: 12}})`
`$gte`	get larger & equal value	`{<field>: {$gte: value }}`	`db.test.find({age: {$gte: 12}})`
`$lte`	get smaller & equal value	`{<field>: {$lte: value }}`	`db.test.find({age: {$lte: 12}})`
`$in`	get data which matched with array of data	`{<field>: {$in: [value, value, value] }}`	`db.test.find({age: {$in: [12, 20, 21, 24]}})`
`$nin`	get data which not matched with array of data	`{<field>: {$nin: [value, value, value] }}`	`db.test.find({age: {$nin: [12, 20, 21, 24]}})`

Logical Operator :

Operator	why use	syntax	example
`$and`	return data if multiple condition is true	`{$and: [exp, exp, exp... exp]}`	`db.test.find({$and: [{age : {$lt: 20} },{'skills.name' : "JAVASCRIPT"},{'skills.name' : "PYTHON"}]}).project({name: 1, age: 1, "skills.name": 1})`
`$or`	if any expression is true return data	`{$or: [exp, exp, exp... exp]}`	`db.test.find({$or: [{age : {$lt: 20} },{'skills.name' : "JAVASCRIPT"},{'skills.name' : "PYTHON"}]}).project({name: 1, age: 1, "skills.name": 1})`
`$not`	if any expression is true return data	`{field:{$not: {operator expression}}}`	`db.test.find({age: {$not: {$gte: 50}}}).sort({age: 1}).project({age: 1})`
`$nor`	selects the documents that fail all of the query expressions in the array.	`{field:{$nor: [exp, exp, exp]}}`	`db.test.find({$nor: [{age: {$in: [7,8,10,12,20,30,40,50,60]}}, {"skills.name": "JAVASCRIPT"}]}).project({age: 1, 'skills.name': 1}).sort({age: 1})` `db.test.find({age: {$not: {$gte: 50}}}).sort({age: 1}).project({age: 1})`

`Implicit` & `Explicit` `$and` in MongoDB.

`Implicit $and` : When we need write multiple condition for `same filed` we can use `implicit` `$and`.

we can separate every condition with comma (,).
syntax:

// we write implicit and for same field.
   {field:  {$gt: 12, $lt: 30}}
// we write implicit and for query with multiple :
   {field: value, field: value, filed: value} // it's also implicit $and

`Explicit $and:`

syntax:

{
   $and: [expression, expression, expression];
}

Example:

db.test
   .find({
      $and: [
         { age: { $gt: 20 } },
         { gender: "Female" },
         { "skills.name": "JAVASCRIPT" },
         { "skills.name": "PYTHON" },
      ],
   })
   .project({ gender: 1, skills: 1 });

Example 2:

db.test
   .find({
      $and: [
         { age: { $gt: 10, $lt: 30 } },
         { gender: "Male" },
         { interests: { $in: ["Gaming", "Reading"] } },
         { "skills.name": { $in: ["JAVASCRIPT"] } },
         { "skills.name": { $in: ["C#"] } },
      ],
   })
   .project({
      age: 1,
      gender: 1,
      interests: 1,
      skills: 1,
   });

`Implicit` and `Explicit` `$or`:

Explicit `$or` :

We can explicitly use $or operator
syntax:

{
   $or: [expression, expression, expression];
}

Example:

// find the user who have skills on Python or Javascript.
db.test
   .find({
      $or: [{ "skills.name": "PYTHON" }, { "skills.name": "JAVASCRIPT" }],
   })
   .project({
      skills: 1,
   });

Implicit $or: we can use implicit for same filed with $in operator.
- $in operator implicitly worked like $or operator.
```
db.test.find({ age: { $in: [10, 20, 30, 40] } });
```
- Nested Array of Object update with ($) (positional) Operator: $ operator update the firstOccurrence from an array
- We can update any normal object with $setOperator.
- When we need to update property element which is an array of object.
- The element stored on any position.
- To find out the element we can use property.$.propertyName : value
- Example:
```
db.another_testing.updateOne(
   {
      _id: ObjectId("6550655ec31abae6aaa3419a"),
      skills: { $elemMatch: { name: "C#" } },
   },
   {
      $set: {
         "skills.$.level": "Expert",
      },
   }
);
```

KakonDebnath/mongodb_master

What is mongoDB ?

Why we use `MongoDB` ?

What is the different between MongoDB & Relational Database.

Main Difference MongDB and Relational Database:

MongoDB Features:

Setup MongoDB in Computer :

`MongoDB Shell` :

Use mongo shell or `mongosh` :

Install `NoSQLBootstar` or `Studio 3T` for graphical User Interface of MongoDB.

MongoDB Shell `Function` & `Operation` :

Projection or `Field Filtering` with MongoDB:

By passing second parameter of `find() or findOne()`:

`projection()` or `project()` method:

`Operator` In MongoDB:-

Thumb Rule : যখন কোনো `Operator` আসবে তখন একটা সেকেন্ড ব্রেকেট `{ }` আনতে হবে।

Comparison Operator :

Logical Operator :

`Implicit` & `Explicit` `$and` in MongoDB.

`Implicit $and` : When we need write multiple condition for `same filed` we can use `implicit` `$and`.

`Explicit $and:`

`Implicit` and `Explicit` `$or`:

Explicit `$or` :

Implicit `$or`: we can use `implicit` for same filed with `$in` operator.

`Nested Array of Object` update with `($)` `(positional)` Operator: `$` operator update the firstOccurrence from an array

KakonDebnath/mongodb_master

What is mongoDB ?

Why we use MongoDB ?

What is the different between MongoDB & Relational Database.

Main Difference MongDB and Relational Database:

MongoDB Features:

Setup MongoDB in Computer :

MongoDB Shell :

Use mongo shell or mongosh :

Install NoSQLBootstar or Studio 3T for graphical User Interface of MongoDB.

MongoDB Shell Function & Operation :

Projection or Field Filtering with MongoDB:

By passing second parameter of find() or findOne():

projection() or project() method:

Operator In MongoDB:-

Thumb Rule : যখন কোনো Operator আসবে তখন একটা সেকেন্ড ব্রেকেট { } আনতে হবে।

Comparison Operator :

Logical Operator :

Implicit & Explicit $and in MongoDB.

Implicit $and : When we need write multiple condition for same filed we can use implicit $and.

Explicit $and:

Implicit and Explicit $or:

Explicit $or :

Implicit $or: we can use implicit for same filed with $in operator.

Nested Array of Object update with ($) (positional) Operator: $ operator update the firstOccurrence from an array

Why we use `MongoDB` ?

`MongoDB Shell` :

Use mongo shell or `mongosh` :

Install `NoSQLBootstar` or `Studio 3T` for graphical User Interface of MongoDB.

MongoDB Shell `Function` & `Operation` :

Projection or `Field Filtering` with MongoDB:

By passing second parameter of `find() or findOne()`:

`projection()` or `project()` method:

`Operator` In MongoDB:-

Thumb Rule : যখন কোনো `Operator` আসবে তখন একটা সেকেন্ড ব্রেকেট `{ }` আনতে হবে।

`Implicit` & `Explicit` `$and` in MongoDB.

`Implicit $and` : When we need write multiple condition for `same filed` we can use `implicit` `$and`.

`Explicit $and:`

`Implicit` and `Explicit` `$or`:

Explicit `$or` :

Implicit `$or`: we can use `implicit` for same filed with `$in` operator.

`Nested Array of Object` update with `($)` `(positional)` Operator: `$` operator update the firstOccurrence from an array