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Relational Databases

What is Cardinality in Databases?

Cardinality, in the context of databases, is a critical concept that has two primary applications: it pertains to the uniqueness of data elements within a column, and it describes the nature of relationships between different tables.

What is a Non-Repeatable Read Anomaly?

Non-Repeatable Read is a database anomaly that occurs in the context of transactions, which are sequences of database operations that should behave as single, indivisible units of work. Non-Repeatable Read happens when a transaction reads the same row twice, and gets different data each time. This is usually due to another transaction modifying the data after the first read. In this post, we look at this concept in detail and techniques to address this.

Understanding SQL Database Isolation Levels

Database isolation is a property that defines how and when the changes made by one operation become visible to other concurrent operations. Isolation is one of the ACID (Atomicity, Consistency, Isolation, Durability) properties.
In this post, we will look at 4 standard isolation levels along with some database-specific ones.

What is ACID in database systems?

ACID is a fundamental concept in database systems, standing for Atomicity, Consistency, Isolation, and Durability. These properties ensure reliable processing of database transactions. ACID Properties of Database Systems Atomicity Atomicity ensures that a transaction is treated as a single, indivisible… Read More »What is ACID in database systems?