Explain OLTP vs OLAP.
OLTP vs OLAP: OLTP (Online Transaction Processing) powers real-time transactions, while OLAP (Online Analytical Processing) enables large-scale analytics and reporting.
When to Use
Use OLTP when your system needs to handle high volumes of inserts, updates, and deletes (e.g., e-commerce orders, ATM withdrawals). Use OLAP for analyzing historical data, running dashboards, or business intelligence queries.
Example
Buying a product online is OLTP; analyzing monthly sales performance is OLAP.
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Why Is It Important
Mixing OLTP and OLAP without separation slows systems down.
Companies often pair OLTP databases with OLAP data warehouses to balance performance and insights.
Interview Tips
Highlight the purpose: OLTP = speed + consistency; OLAP = deep queries + aggregated insights.
Use short examples to impress interviewers and mention why enterprises keep them separate.
Trade-offs
OLTP gives fast transactions but struggles with heavy analytics.
OLAP handles big queries efficiently but can’t support real-time transaction speed.
Pitfalls
A common mistake is running analytical reports directly on OLTP databases—this can overload transaction systems. Another is assuming OLAP data is always real-time; it’s often batch-updated.
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