DBMS Basics Made Easy

This document provides a list of basic Database Management System (DBMS) concepts and commands to help you get started with understanding and using databases effectively.

Introduction to DBMS

• DBMS: Software that uses a standard method to store and organize data.
• RDBMS: Relational Database Management System, a type of DBMS based on the relational model.

Key Concepts

• Database: An organized collection of data.
• Table: A collection of related data entries consisting of rows and columns.
• Schema: The structure that defines the organization of data in a database.

SQL Basics

• SQL: Structured Query Language, used to communicate with databases.
• SELECT: Retrieve data from a database.
• INSERT: Add new data to a database.
• UPDATE: Modify existing data in a database.
• DELETE: Remove data from a database.

Data Types

• Integer: Whole numbers.
• Varchar: Variable-length string.
• Date: Date values.

Constraints

• Primary Key: Uniquely identifies each record in a table.
• Foreign Key: A field in one table that uniquely identifies a row of another table.
• Unique: Ensures all values in a column are unique.
• Not Null: Ensures a column cannot have a NULL value.

Normalization

• Normalization: Process of organizing data to reduce redundancy.
• 1NF (First Normal Form): Ensures each column contains atomic values.
• 2NF (Second Normal Form): Ensures all non-key attributes are fully functional dependent on the primary key.
• 3NF (Third Normal Form): Ensures no transitive dependency for non-prime attributes.

Indexing

• Index: A database object that improves the speed of data retrieval.
• Clustered Index: Sorts and stores the data rows in the table based on their key values.
• Non-Clustered Index: Contains a sorted list of references to the table data.

Transactions

• Transaction: A sequence of database operations that are treated as a single unit.
• ACID Properties: Ensures reliable processing of database transactions.
  • Atomicity: Ensures that all operations within a transaction are completed successfully.
  • Consistency: Ensures the database remains in a consistent state before and after the transaction.
  • Isolation: Ensures that transactions are securely and independently processed.
  • Durability: Ensures that the results of a transaction are permanently stored in the database.

Backup and Recovery

• Backup: Creating a copy of the database to protect against data loss.
• Recovery: Restoring the database to a correct state in case of failure.

These concepts and commands should help you get started with basic DBMS understanding and usage.