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Data Warehousing Informatica - Interview Questions and Answers
What is the difference between OLTP and OLAP?

OLTP (Online Transaction Processing) and OLAP (Online Analytical Processing) are two distinct types of data processing systems, each designed for different purposes. Here's a breakdown of their key differences:

OLTP (Online Transaction Processing) :

  • Purpose:
    • Designed for real-time transaction processing.
    • Focuses on handling a large number of short, concurrent transactions.
    • Used for day-to-day operational tasks.
  • Characteristics:
    • Emphasis on speed and efficiency of individual transactions.
    • High transaction volume.
    • Data is typically current and detailed.
    • Relational databases are commonly used.
    • Prioritizes data integrity and availability.
  • Examples:
    • ATM transactions.
    • Online shopping transactions.
    • Banking transactions.
    • Order entry systems.

OLAP (Online Analytical Processing) :

  • Purpose:
    • Designed for complex data analysis and decision support.
    • Focuses on analyzing large volumes of historical data.
    • Used for business intelligence and reporting.
  • Characteristics:
    • Emphasis on analytical queries and data summarization.
    • Large data volumes.
    • Data is typically historical and aggregated.
    • Data warehouses and data marts are commonly used.
    • Prioritizes query performance for complex analysis.
  • Examples:
    • Sales trend analysis.
    • Financial forecasting.
    • Market analysis.
    • Business performance reporting.

Key Differences Summarized :

  • Data Nature:
    • OLTP: Current, detailed, transactional data.
    • OLAP: Historical, aggregated, analytical data.
  • Purpose:
    • OLTP: Transaction processing.
    • OLAP: Data analysis.
  • Query Type:
    • OLTP: Short, simple transactions.
    • OLAP: Complex analytical queries.
  • Database Design:
    • OLTP: Normalized databases.
    • OLAP: Denormalized databases (e.g., star schema, snowflake schema).
  • Performance:
    • OLTP: High transaction throughput, fast response times for individual transactions.
    • OLAP: Fast response times for complex analytical queries.