Database triggers can be very useful, but like any tool, they have their advantages and disadvantages. Here are some of the pros and cons of using database triggers: Pros of Database Triggers Data Integrity Triggers can enforce business rules at… Read More »What are Pros & Cons of Database Triggers?
Copying Only Data You can create a copy of an existing table in SQL by using the CREATE TABLE AS statement. This statement creates a new table and fills it with data computed by a SELECT command. The data types… Read More »How do you create a copy of an existing table in SQL?
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.
Introduction The dynamics of database management prioritize efficient data retrieval as a key performance index. Herein lies the significance of database statistics, which provide a snapshot of database content like row counts in a table or value distributions within a… Read More »What is the Importance of Database Statistics in Query Optimization?
Introduction A phantom read is a scenario that occurs in a database when a transaction re-executes a query and finds that another committed transaction has added or removed rows that weren’t there previously. This anomaly can lead to inconsistencies in… Read More »What is a Phantom 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.
What is a Dirty Read By definition, a dirty read occurs when a transaction reads data from another transaction that has not yet been committed. The “dirty” moniker refers to the potential unstable state of the data, as it is… Read More »How do ‘Dirty Reads’ Impact Database Consistency?
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?
Introduction to EXPLAIN Plains An EXPLAIN plan, often simply called an “explain”, is a tool in SQL-based database systems like PostgreSQL that provides information about how a database will execute a given query. By inputting a SQL query to the… Read More »What is an EXPLAIN Plan? How is it interpreted?
A SQL Injection is a code injection technique that attackers use to exploit vulnerabilities in a web application’s database layer. This vulnerability is often present in a web application when user input is incorrectly filtered for string literals that are used in SQL statements, or when user input is not strongly typed and can unexpectedly execute SQL commands.
The technique allows an attacker to manipulate SQL queries that an application makes to its database, enabling the attacker to view, alter, or delete data that they are not normally authorized to access.