Yashotantra Academy logo
← SQL & Databases theorytheory 0/3 · 0%
level 1
Curious · 0 XP
streak
0d
perfect
0
badges
0

100 XP to Apprentice

Transactions · easy

1. ACID Guarantees & Transaction Isolation Levels

Atomicity, Consistency, Isolation, and Durability.

1 min read2 questionsup to 50 XPtopic 1/3

Read in another language

AI translates the explanation and quiz text while preserving code and answer scoring.

Relational engines enforce ACID properties. SQL standard isolation levels manage concurrency anomalies: - Read Uncommitted: Dirty reads possible. - Read Committed: Default in PostgreSQL; avoids dirty reads. - Repeatable Read: Snapshot isolation; avoids non-repeatable reads. - Serializable: Strictest level; eliminates phantom reads and serialization anomalies.

How to study this topic

  1. 1. Read the explanation once end to end, skipping the code.
  2. 2. Re-read the code snippets and say out loud what each line does.
  3. 3. Answer the quiz without scrolling back — that is the real check.
  4. 4. Read every explanation, even for the answers you got right.

Scoring

  • · Up to 30 XP from quiz accuracy.
  • · +15 XP for a perfect first attempt.
  • · +5 XP while a 3-day streak is running.
  • · 75% or higher marks the topic complete.

Check your understanding

  1. 1. Which isolation level is the default in PostgreSQL?

  2. 2. What phenomenon occurs when a transaction reads uncommitted changes from another transaction?

Badges

First light
Pass your first topic
Sharp shooter
3 perfect first-try quizzes
On a roll
Study 3 days in a row
Week warrior
Study 7 days in a row
Grinder
Earn 500 XP
Deep diver
Earn 1500 XP