Databases (DB) are crucial for developers to understand as they underpin modern applications.

1. Data Models

There are two primary data models to be aware of:

• Relational Databases: Use structured query language (SQL) and tables.
• NoSQL Databases: Flexible schemas, used for unstructured data, such as documents and key-value pairs.

2. CRUD Operations

Understanding basic CRUD (Create, Read, Update, Delete) operations is essential:

• Create: Inserting new records.
• Read: Querying existing records.
• Update: Modifying existing records.
• Delete: Removing records.

3. Indexing

Indexes improve the speed of data retrieval:

• B-Tree Index: Standard index type in relational databases.
• Full-Text Index: Optimized for full-text searches.

4. Transactions

Transactions ensure data integrity:

• Atomicity: All tasks in a transaction must complete.
• Consistency: The database must be in a valid state before and after the transaction.
• Isolation: Transactions are isolated from each other until they complete.
• Durability: Once a transaction is committed, it must remain so, even in the case of a failure.

5. Normalization

Normalizing data reduces redundancy:

• 1NF: Ensures each column contains atomic values.
• 2NF: Prevents partial dependency on a composite primary key.
• 3NF: Eliminates transitive dependency.

6. Database Security

Protecting sensitive data is paramount:

• Authentication: Verifying user identity.
• Authorization: Granting permissions to confirmed users.
• Encryption: Protecting data at rest and in transit.

7. High Availability & Scalability

Ensuring databases remain available and can handle growth:

• Replication: Copying data across multiple servers.
• Partitioning: Splitting data across multiple databases for performance.
• Load Balancing: Distributing requests evenly across servers.

QA Section

Q: What is the difference between SQL and NoSQL?

A: SQL databases use structured schema and tables, while NoSQL accommodates unstructured data.

Q: How does indexing impact performance?

A: Indexing significantly speeds up data retrieval, reducing search time in large datasets.

Mind Map

Key Features of Databases:

• Data Models
• CRUD Operations
• Indexing
• Transactions
• Normalization
• Database Security
• High Availability & Scalability

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