Explore the fundamentals of databases, including design, management, and querying techniques. Learn about SQL, NoSQL, and best practices for data storage!
Query Collections Duplicate value Delete Duplicate Records While Keeping One Efficiently remove duplicates but keep one copy. Nth Largest Value Replace query This query will be helpful if you want to replace a part of the string in the table. Detect missing values in a sequence Sample Table id 1 4 6 Output id 2 … Read more
When Sun Microsystems acquired MySQL in 2008, the future looked bright for this widely-used open-source database. However, things took a sharp turn when Oracle Corporation, a major player in proprietary software, acquired Sun the following year. Concerns quickly grew within the open-source community, and many feared Oracle might alter MySQL’s development course, potentially shifting it … Read more
SQL wildcards (% and _) can be powerful for pattern matching, but they can also have performance implications, especially on large datasets. Here’s a breakdown of their usage and impact on performance: Leading Wildcards (%pattern) Performance Impact: Using a leading % disables index usage, as the database must perform a full scan to find matches. … Read more
Database engines (or storage engines) are the underlying systems that manage how data is stored, retrieved, and manipulated within a database. Each engine has its own unique set of features, optimizations, and limitations. MySQL, one of the most popular open-source SQL databases, supports multiple storage engines, the most widely used being MyISAM and InnoDB. Other … Read more
SQL query optimization is essential to ensure your database applications run smoothly and efficiently, especially as data grows. Optimized SQL queries can significantly improve response times, reduce server load, and enhance the user experience. This guide provides a step-by-step approach to optimizing SQL queries, covering best practices, tips, and strategies to make your queries faster … Read more
The EXPLAIN statement in SQL is a powerful diagnostic tool that helps you understand and optimize your database queries, especially in relational databases like MySQL. By using EXPLAIN, you can see how your queries interact with your tables, which indexes are used, and the estimated costs of each operation. Understanding the output of EXPLAIN is … Read more
ACID stands for Atomicity, Consistency, Isolation, and Durability. Together, these principles define how transactions behave and help prevent data corruption, even when issues like hardware failures, power outages, or concurrent data access arise. Let’s break down each of these properties to understand their significance in SQL transactions. What is a Database Transaction? Before diving into … Read more
SQL Window Functions are powerful tools that allow users to perform calculations across a set of table rows related to the current row. What is a Window Function? A window function performs a calculation across a set of table rows that are somehow related to the current row. This set of rows is referred to … Read more
Apache Cassandra is a highly scalable, distributed NoSQL database designed to handle large amounts of data across many servers, providing high availability with no single point of failure. This practical guide will help you understand how to use Cassandra for real-world applications. Key Points Key Concepts in Cassandra Login in console Keyspace A keyspace is … Read more