44.1 ACID Concepts
This topic teaches ACID Concepts as part of Transactions. Learn the purpose first, then inspect the syntax and test it with small inputs before using it in production.
Code example
<?php
// ACID Concepts
$value = 42;
echo "PHP example: $value\n";Step-by-step explanation
- Identify the values, objects, tables, or resources used by the example.
- Read each statement in execution order.
- Predict what the program or query should produce.
- Run it in a safe local/test environment.
- Change one input and explain the new result.
Expected output/result
You should see a small result that demonstrates ACID Concepts. Exact formatting can differ by runtime, client, database state, operating system, or tool version.
Common mistakes
Watch for invalid input, unchecked errors, incorrect type assumptions, missing cleanup, unsafe permissions, injection risks, or code/query logic that handles only the happy path.
Practice exercise
Rebuild this example with your own data. Add one edge case, predict the result before running it, and explain why the final result is correct.
44.2 BEGIN/COMMIT
This topic teaches BEGIN/COMMIT as part of Transactions. Learn the purpose first, then inspect the syntax and test it with small inputs before using it in production.
Code example
<?php
// BEGIN/COMMIT
$value = 42;
echo "PHP example: $value\n";Step-by-step explanation
- Identify the values, objects, tables, or resources used by the example.
- Read each statement in execution order.
- Predict what the program or query should produce.
- Run it in a safe local/test environment.
- Change one input and explain the new result.
Expected output/result
You should see a small result that demonstrates BEGIN/COMMIT. Exact formatting can differ by runtime, client, database state, operating system, or tool version.
Common mistakes
Watch for invalid input, unchecked errors, incorrect type assumptions, missing cleanup, unsafe permissions, injection risks, or code/query logic that handles only the happy path.
Practice exercise
Rebuild this example with your own data. Add one edge case, predict the result before running it, and explain why the final result is correct.
44.3 Rollback
This topic teaches Rollback as part of Transactions. Learn the purpose first, then inspect the syntax and test it with small inputs before using it in production.
Code example
<?php
// Rollback
$value = 42;
echo "PHP example: $value\n";Step-by-step explanation
- Identify the values, objects, tables, or resources used by the example.
- Read each statement in execution order.
- Predict what the program or query should produce.
- Run it in a safe local/test environment.
- Change one input and explain the new result.
Expected output/result
You should see a small result that demonstrates Rollback. Exact formatting can differ by runtime, client, database state, operating system, or tool version.
Common mistakes
Watch for invalid input, unchecked errors, incorrect type assumptions, missing cleanup, unsafe permissions, injection risks, or code/query logic that handles only the happy path.
Practice exercise
Rebuild this example with your own data. Add one edge case, predict the result before running it, and explain why the final result is correct.
44.4 Isolation
This topic teaches Isolation as part of Transactions. Learn the purpose first, then inspect the syntax and test it with small inputs before using it in production.
Code example
<?php
// Isolation
$value = 42;
echo "PHP example: $value\n";Step-by-step explanation
- Identify the values, objects, tables, or resources used by the example.
- Read each statement in execution order.
- Predict what the program or query should produce.
- Run it in a safe local/test environment.
- Change one input and explain the new result.
Expected output/result
You should see a small result that demonstrates Isolation. Exact formatting can differ by runtime, client, database state, operating system, or tool version.
Common mistakes
Watch for invalid input, unchecked errors, incorrect type assumptions, missing cleanup, unsafe permissions, injection risks, or code/query logic that handles only the happy path.
Practice exercise
Rebuild this example with your own data. Add one edge case, predict the result before running it, and explain why the final result is correct.
44.5 Deadlocks and Retry
This topic teaches Deadlocks and Retry as part of Transactions. Learn the purpose first, then inspect the syntax and test it with small inputs before using it in production.
Code example
<?php
// Deadlocks and Retry
$value = 42;
echo "PHP example: $value\n";Step-by-step explanation
- Identify the values, objects, tables, or resources used by the example.
- Read each statement in execution order.
- Predict what the program or query should produce.
- Run it in a safe local/test environment.
- Change one input and explain the new result.
Expected output/result
You should see a small result that demonstrates Deadlocks and Retry. Exact formatting can differ by runtime, client, database state, operating system, or tool version.
Common mistakes
Watch for invalid input, unchecked errors, incorrect type assumptions, missing cleanup, unsafe permissions, injection risks, or code/query logic that handles only the happy path.
Practice exercise
Rebuild this example with your own data. Add one edge case, predict the result before running it, and explain why the final result is correct.
10 Questions & Answers
1. What should you know about ACID Concepts?
Know the purpose, syntax, inputs, result, edge cases, common errors, and the security or performance concern where applicable.
2. What should you know about BEGIN/COMMIT?
Know the purpose, syntax, inputs, result, edge cases, common errors, and the security or performance concern where applicable.
3. What should you know about Rollback?
Know the purpose, syntax, inputs, result, edge cases, common errors, and the security or performance concern where applicable.
4. What should you know about Isolation?
Know the purpose, syntax, inputs, result, edge cases, common errors, and the security or performance concern where applicable.
5. What should you know about Deadlocks and Retry?
Know the purpose, syntax, inputs, result, edge cases, common errors, and the security or performance concern where applicable.
6. What should you know about ACID Concepts?
Know the purpose, syntax, inputs, result, edge cases, common errors, and the security or performance concern where applicable.
7. What should you know about BEGIN/COMMIT?
Know the purpose, syntax, inputs, result, edge cases, common errors, and the security or performance concern where applicable.
8. What should you know about Rollback?
Know the purpose, syntax, inputs, result, edge cases, common errors, and the security or performance concern where applicable.
9. What should you know about Isolation?
Know the purpose, syntax, inputs, result, edge cases, common errors, and the security or performance concern where applicable.
10. What should you know about Deadlocks and Retry?
Know the purpose, syntax, inputs, result, edge cases, common errors, and the security or performance concern where applicable.