Repeatable read behavior in PostgreSQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start a transaction with repeatable read isolation level.

PostgreSQL

BEGIN TRANSACTION ISOLATION LEVEL [1];

Drag options to blanks, or click blank then click option'

Aread committed

Bread uncommitted

Crepeatable read

Dserializable

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'read committed' which allows non-repeatable reads.

Using 'serializable' which is stricter than repeatable read.

The repeatable read isolation level ensures that all reads within the transaction see a consistent snapshot of the database.

2fill in blank

medium

Complete the code to set the transaction isolation level to repeatable read using SET command.

PostgreSQL

SET TRANSACTION ISOLATION LEVEL [1];

Drag options to blanks, or click blank then click option'

Arepeatable read

Bread uncommitted

Cread committed

Dserializable

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing 'repeatable read' with 'read committed'.

Using 'serializable' which is stricter.

Using SET TRANSACTION ISOLATION LEVEL repeatable read sets the isolation level for the current transaction.

3fill in blank

hard

Fix the error in the transaction start statement to use repeatable read isolation level.

PostgreSQL

BEGIN TRANSACTION ISOLATION [1];

Drag options to blanks, or click blank then click option'

Alevel repeatable read

Bisolation level repeatable read

Crepeatable_read

Drepeatable read

Attempts:

3 left

💡 Hint

Common Mistakes

Using underscores instead of spaces.

Including extra keywords in the blank.

The correct syntax is BEGIN TRANSACTION ISOLATION LEVEL repeatable read; but since LEVEL is missing, the correct fix is to add the full phrase. Here, the blank replaces only the isolation level name, so 'repeatable read' is correct.

4fill in blank

hard

Fill both blanks to complete the query that shows the current transaction isolation level.

PostgreSQL

SHOW [1] [2];

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Atransaction

Bisolation

Clevel

Dmode

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'transaction mode' which is invalid.

Using 'isolation mode' which is invalid.

The correct command is SHOW transaction isolation level; which displays the current isolation level.

5fill in blank

hard

Fill all three blanks to complete the SQL that sets repeatable read isolation level and starts a transaction.

PostgreSQL

[1] TRANSACTION [2] LEVEL [3];

Drag options to blanks, or click blank then click option'

ABEGIN

BISOLATION

Crepeatable read

DSTART

Attempts:

3 left

💡 Hint

Common Mistakes

Using BEGIN without ISOLATION keyword.

Using 'repeatable_read' with underscore.

The correct syntax is START TRANSACTION ISOLATION LEVEL repeatable read; which begins a transaction with the specified isolation level.