README - Transaction Isolation Levels and Anomalies

This README file provides a comparison of transaction isolation levels in PostgreSQL and MariaDB and how they relate to common transaction anomalies such as Dirty Read, Non-repeatable Reads, Phantom Reads, and Lost Update.

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PostgreSQL Transaction Isolation Levels

1. READ UNCOMMITTED:

   • Dirty Read: Happened
   • Non-repeatable Reads: Happened
   • Phantom Reads: Happened
   • Lost Update: Not Happened

2. READ COMMITTED:

   • Dirty Read: Not Happened
   • Non-repeatable Reads: Not Happened
   • Phantom Reads: Not Happened
   • Lost Update: Not Happened

3. REPEATABLE READ:

   • Dirty Read: Not Happened
   • Non-repeatable Reads: Happened
   • Phantom Reads: Not Happened
   • Lost Update: Not Happened

4. SERIALIZABLE:

   • Dirty Read: Not Happened
   • Non-repeatable Reads: Not Happened
   • Phantom Reads: Not Happened
   • Lost Update: Not Happened

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MariaDB Transaction Isolation Levels

1. READ UNCOMMITTED:

   • Dirty Read: Happened
   • Non-repeatable Reads: Happened
   • Phantom Reads: Happened
   • Lost Update: Not Happened

2. READ COMMITTED:

   • Dirty Read: Not Happened
   • Non-repeatable Reads: Not Happened
   • Phantom Reads: Not Happened
   • Lost Update: Not Happened

3. REPEATABLE READ:

   • Dirty Read: Not Happened
   • Non-repeatable Reads: Happened
   • Phantom Reads: Not Happened
   • Lost Update: Not Happened

4. SERIALIZABLE:

   • Dirty Read: Not Happened
   • Non-repeatable Reads: Not Happened
   • Phantom Reads: Not Happened
   • Lost Update: Not Happened