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Sri Raghavendra Educational Institutions Society (R)

(Approved by AICTE, Accredited by NAAC, Affiliated to VTU, Karnataka)

Sri Krishna Institute of Technology

www.skit.org.in

Title: Terms used in RDBMS and MongoDB

CO addressed: CO2

Course: Big Data Analytics

Presented by: Mr. P. Kiran Kumar

Department: ISE

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Introduction to RDBMS and MongoDB Terms

RDBMS

RDBMS stands for Relational Database Management System.
Stores data in tables consisting of rows and columns.
Uses SQL (Structured Query Language) to manage data.
Supports relationships between tables using keys.
Examples: MySQL, Oracle, PostgreSQL, SQL Server

MongoDB

MongoDB is a NoSQL document-oriented database.
Stores data in collections as JSON-like documents.
Uses MongoDB Query Language (MQL) to work with data.
Provides a flexible schema for storing different types of data.
Suitable for large-scale and rapidly changing applications.

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Structural Terms: RDBMS vs MongoDB

1. Database

A container used to store and organize data.
RDBMS: Contains tables.
MongoDB: Contains collections.

2. Table / Collection

Table: Stores related data in an RDBMS.
Collection: Stores related documents in MongoDB.

3. Row / Document

Row: A single record in an RDBMS table.
Document: A single record stored in MongoDB.
MongoDB documents use JSON-like BSON format.

4. Column / Field

Column: Defines an attribute of a table.
Field: Defines an attribute inside a MongoDB document.

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Primary Key, _id and Foreign Key/Reference

1. Primary Key

Uniquely identifies each record in an RDBMS table.
Cannot contain duplicate values.
Example: Student_ID

2. _id in MongoDB

Every MongoDB document has a unique _id field.
Acts as the primary key of the document.
MongoDB automatically generates an ObjectId if _id is not provided.

3. Foreign Key

Used in RDBMS to link records between two tables.
Refers to the primary key of another table.
Example: Department_ID in Student table.

4. Reference in MongoDB

MongoDB can store a reference to a document in another collection.
Commonly uses the _id of the referenced document.

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Example

In RDBMS:

Student

Student_ID | Name | Dept_ID

101 | Ravi | D01

Department

Dept_ID | Dept_Name

D01 | CSE

MongoDB

{

"_id": 101,

"name": "Ravi",

"dept_id": "D01"

}

Key Point:

Primary Key ↔ _id

Foreign Key ↔ Reference

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Relationships and Joins: JOIN, Embedding, $lookup

1. JOIN in RDBMS

Combines data from two or more tables.
Uses a related column between tables.
Common types: INNER JOIN, LEFT JOIN, RIGHT JOIN.
Example: Joining Student and Department tables using Dept_ID.

2. Embedding in MongoDB

Stores related data inside the same document.
Reduces the need for joins.
Suitable for data that is frequently accessed together.

3. $lookup in MongoDB

Used to combine documents from different collections.
Performs a join-like operation.
Used within the aggregation pipeline.

{

"_id": 101,

"name": "Ravi",

"department": {

"id": "D01",

"name": "CSE"

}

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Indexing and Querying: Index, SQL Query, Find Query

1. Index

An index improves the speed of data retrieval.
RDBMS and MongoDB both support indexing.

Example: Index on Student_ID or name.

2. SQL Query – RDBMS

SQL is used to retrieve and manipulate data.

Example:

SELECT * FROM Student

WHERE name = 'Ravi';

3. Find Query – MongoDB

MongoDB uses the find() method to retrieve documents.
Supports filtering based on field values.

Example:

db.students.find({ name: "Ravi" })

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Aggregation and Transactions

1. Aggregation Pipeline – MongoDB

Used to process and analyze documents.
Data passes through multiple stages.
Common stages: $match, $group, $sort.
Similar to performing data filtering, grouping, and calculations in SQL.

2. ACID Transactions

Transactions ensure reliable database operations.

A – Atomicity: All operations succeed or none are applied.
C – Consistency: Data remains valid.
I – Isolation: Transactions do not interfere with each other.
D – Durability: Committed changes are permanently saved.

3. Commit and Rollback

Commit: Permanently saves the transaction
Rollback: Cancels changes made during the transaction

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Performance and Scaling

1. Vertical Scaling

Increases CPU, RAM, or storage of a single server.
Suitable for improving the capacity of one system.

2. Horizontal Scaling

Adds multiple servers to distribute the workload.
Helps handle increasing users and data.

3. Sharding

Distributes data across multiple servers (shards).
Improves scalability for large datasets and high traffic.

4. Replication

Maintains multiple copies of data on different servers.
Provides high availability and fault tolerance.

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Backup, Recovery and Data Integrity

1. mongodump

Creates a backup of MongoDB databases.
Stores database data in a dump directory.

2. mongorestore

Restores MongoDB data from a backup.
Used to recover databases after data loss.

3. Oplog

Records changes made to data in a replica set.
Helps with replication and recovery.

4. Change Streams

Allows applications to listen for real-time data changes.
Detects operations such as insert, update, and delete

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Security and Authentication

1. RBAC – Role-Based Access Control

Assigns roles and permissions to users.
Controls which database operations a user can perform.

2. LDAP – Lightweight Directory Access Protocol

Provides centralized user authentication.
Commonly used to manage users and groups in organizations.

3. Kerberos

Provides secure authentication using tickets.
Helps verify the identity of users and services.

4. SCRAM – Salted Challenge Response Authentication Mechanism

A username and password-based authentication mechanism.
MongoDB uses SCRAM to authenticate database users securely.

5. Encryption

Protects data from unauthorized access.
Can protect data in transit and at rest.

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MongoDB Database Commands

1. Create / Switch Database

Use use to create or switch to a database.
Database is created when data is first stored.

2. Verify Current Database

Use db to display the current database.
Helps verify which database is selected.

3. List Databases

Use show dbs to display available databases.
Shows databases that contain stored data.

4. Drop Database

Deletes the current database and its data.
Use carefully because the operation removes the database.
db.dropDatabase()

// Create / Switch to database

use collegeDB

// Insert data to create the database

db.students.insertOne({

_id: 101,

name: "Ravi",

department: "CSE"

})

// Drop the database

db.dropDatabase()