Database Query Processing Overview

Static Index

• Used to retrieve data faster by reducing comparisons
• Data does not change frequently
• Optimizes query performance
• Reduces time to retrieve data
• Reduces number of rows
• Organized like a B-tree

Query Processing

• Processes queries from high level to lower level (parsing, validating, optimizing)
• Parsing:
  • Syntax check (ensuring correct structure)
  • Semantic check (checking if statements function)
  • Shared Pool check (checking if a hash code already exists)
• Parse Tree:
  • Tree-like grammatical structure
  • Hierarchical structure
  • Represents the query's grammar
  • Used for syntax validation and visualization of the query structure

Translation, Optimization, and Evaluation

• Translation: Converts high-level queries into intermediate SQL queries
• Optimization: Finds the most efficient way to execute a query, using:
  • Heuristic optimization (using predefined rules)
  • Cost-based optimization (considering CPU, RAM, disk usage)
• Evaluation: Executes SQL queries, using:
  • JOIN
  • WHERE
  • SELECT
  • ORDER BY

DBMS Security

• Protects databases from unintentional outcomes
• Maintains confidentiality, integrity, and availability
• Key Components:
  • Authentication (verifies user)
  • Authorization (grants permissions)
  • Encryption (protects data)
  • Auditing (tracks activity)
• Data Security: Protects data from unauthorized actions
• How to Secure Data:
  • Encryption (converting into code)
  • Regular data backups (stored securely)
  • Firewalls and intrusion detection systems (monitor network traffic)

Security Measures for DBMS

• Firewalls and Network Security: Prevents unauthorized access
• Data Encryption: Hides/encrypts data to protect against theft
• Role-Based Access Control: Assigns specific roles
• Regular Patching and Updates: Addresses vulnerabilities
• Backup Recovery: Prevents data loss
• Encryption in Database Security:
  • Symmetric encryption (same key for encryption and decryption)
  • Asymmetric encryption (public key for encryption, private for decryption)
• Auditing and Monitoring:
  • Database auditing (logs access attempts and data changes)
  • Monitoring tools (tracks activity)
• Backup and Recovery Strategies:
  • Full backups (complete copy of database)
  • Incremental backups (changes since last backup)

Explore the fundamentals of database query processing, including static indexing, parsing, and optimization strategies. Understand how these concepts enhance query performance by reducing retrieval time and organizing data efficiently.