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Manoj Kumar

a cse student

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Modifying Tables Safely in PostgreSQL — ALTER TABLE, Constraints, and Defaults

Modifying Tables Safely in PostgreSQL — ALTER TABLE, Constraints, and Defaults

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4 min read
PostgreSQL Table Design — Constraints, Defaults, and Foreign Keys Explained Simply

PostgreSQL Table Design — Constraints, Defaults, and Foreign Keys Explained Simply

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1 min read
Handling Duplicate Transfers in PostgreSQL — Idempotency and How Real Payment Systems Stay Safe

Handling Duplicate Transfers in PostgreSQL — Idempotency and How Real Payment Systems Stay Safe

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4 min read
Does Your Payment Data Survive a Crash? Testing Durability in PostgreSQL

Does Your Payment Data Survive a Crash? Testing Durability in PostgreSQL

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4 min read
Concurrent Transactions in PostgreSQL — Isolation Levels, Dirty

Concurrent Transactions in PostgreSQL — Isolation Levels, Dirty

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5 min read
How PostgreSQL Keeps Your Wallet Data Honest — Constraints, Violations, and Consistency

How PostgreSQL Keeps Your Wallet Data Honest — Constraints, Violations, and Consistency

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4 min read
Building a Safe Money Transfer System in PostgreSQL — Transactions, Rollbacks, and What Happens When Things Break

Building a Safe Money Transfer System in PostgreSQL — Transactions, Rollbacks, and What Happens When Things Break

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3 min read
Sakila SQL Practice — User Roles, Permissions, and Access Control in PostgreSQL

Sakila SQL Practice — User Roles, Permissions, and Access Control in PostgreSQL

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3 min read
Sakila SQL Practice — Filtering, Pattern Matching, and Pagination Queries

Sakila SQL Practice — Filtering, Pattern Matching, and Pagination Queries

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4 min read
the Sakila database

the Sakila database

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3 min read
HackerRank SQL — Querying Every Row and Column from the CITY Table

HackerRank SQL — Querying Every Row and Column from the CITY Table

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1 min read
HackerRank SQL — Finding the Difference Between Total and Distinct City Counts

HackerRank SQL — Finding the Difference Between Total and Distinct City Counts

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1 min read
HackerRank SQL — All Details of American Cities with Population Over 100000

HackerRank SQL — All Details of American Cities with Population Over 100000

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1 min read
HackerRank SQL — Pulling City and State from the STATION Table

HackerRank SQL — Pulling City and State from the STATION Table

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1 min read
HackerRank SQL — City Names That Do Not Start With Vowels

HackerRank SQL — City Names That Do Not Start With Vowels

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1 min read
HackerRank SQL — Getting American City Names with Population Over 120000

HackerRank SQL — Getting American City Names with Population Over 120000

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1 min read
HackerRank SQL — Fetching All Japanese Cities from the CITY Table

HackerRank SQL — Fetching All Japanese Cities from the CITY Table

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1 min read
Solving HackerRank Basic Select — Query All Columns for a City by ID

Solving HackerRank Basic Select — Query All Columns for a City by ID

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1 min read
Setup a DNS hosted zone in Route53 in AWS

Setup a DNS hosted zone in Route53 in AWS

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2 min read
simple EC2 instance and run a webserver and access it from outside

simple EC2 instance and run a webserver and access it from outside

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2 min read
how DNS resolver is happening

how DNS resolver is happening

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2 min read
How a request originates from cllient and reaches the server ?

How a request originates from cllient and reaches the server ?

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2 min read
blog on IP address and Subnet

blog on IP address and Subnet

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2 min read
CA 15 - Merge Two Linked List

CA 15 - Merge Two Linked List

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2 min read
Merge Sort for Linked List – Python

Merge Sort for Linked List – Python

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2 min read
Remove Duplicates from a Sorted Linked List – Python

Remove Duplicates from a Sorted Linked List – Python

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2 min read
Reverse a Linked List – Python (Step-by-Step)

Reverse a Linked List – Python (Step-by-Step)

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1 min read
Majority Element – Python (Boyer-Moore Algorithm)

Majority Element – Python (Boyer-Moore Algorithm)

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2 min read
Search in Rotated Sorted Array – Python

Search in Rotated Sorted Array – Python

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2 min read
First and Last Occurrence in Sorted Array – Python

First and Last Occurrence in Sorted Array – Python

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2 min read
Squares of a Sorted Array – Python (Two Pointer Approach)

Squares of a Sorted Array – Python (Two Pointer Approach)

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2 min read
Different Sorting Methodologies in Python – Complete Guide

Different Sorting Methodologies in Python – Complete Guide

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2 min read
Guess Number Higher or Lower – Python (Binary Search)

Guess Number Higher or Lower – Python (Binary Search)

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2 min read
Valid Anagram – Python Solution

Valid Anagram – Python Solution

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1 min read
Move Zeroes – Python (In-Place Solution)

Move Zeroes – Python (In-Place Solution)

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1 min read
Next Permutation – Python (Step-by-Step Explanation)

Next Permutation – Python (Step-by-Step Explanation)

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2 min read
Kadane’s Algorithm – Maximum Subarray Sum (Python)p2

Kadane’s Algorithm – Maximum Subarray Sum (Python)p2

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2 min read
Kadane’s Algorithm – Maximum Subarray Sum (Python)

Kadane’s Algorithm – Maximum Subarray Sum (Python)

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2 min read
Move All Negative Elements to End – Python

Move All Negative Elements to End – Python

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2 min read
Sort 0s, 1s and 2s – Python (Dutch National Flag Algorithm)

Sort 0s, 1s and 2s – Python (Dutch National Flag Algorithm)

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2 min read
Kth Smallest Element in an Array – Python

Kth Smallest Element in an Array – Python

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2 min read
Find Minimum and Maximum in an Array – Python

Find Minimum and Maximum in an Array – Python

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1 min read
Reverse an Array – Python Solution

Reverse an Array – Python Solution

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1 min read
Two Sum II – Input Array Is Sorted (Python)

Two Sum II – Input Array Is Sorted (Python)

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2 min read
Two Sum Problem – Python Solution

Two Sum Problem – Python Solution

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2 min read
CA 03 – Number Guessing Game Leaderboard (Python)

CA 03 – Number Guessing Game Leaderboard (Python)

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2 min read
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