Category: SQL

In SQL, a trigger is a set of instructions that are automatically executed or fired in response to certain events on a particular table or view. The ALTER TRIGGER statement is used to modify an existing trigger in a database. Triggers are commonly used to enforce business rules, maintain referential integrity, or perform other automated…(Continue Reading)

In SQL, the ALTER VIEW statement is used to modify an existing view in a database. A view in SQL is a virtual table that is based on the result of a SELECT query. It does not store the data itself but provides a way to represent the data from one or more tables in…(Continue Reading)

The SET TRANSACTION statement in SQL is used to configure properties for a transaction. Transactions in a relational database management system (RDBMS) ensure the consistency and integrity of the data by allowing a series of SQL statements to be treated as a single unit of work. The SET TRANSACTION statement provides a way to customize…(Continue Reading)

In SQL, a SAVEPOINT is a mechanism that allows you to create a point within a transaction to which you can later roll back. This feature is particularly useful when you want to implement a partial rollback in case of errors or other exceptional conditions within a transaction. Why Use SAVEPOINT? Nested Transactions SAVEPOINT allows…(Continue Reading)

The BEGIN TRANSACTION statement is a fundamental part of the SQL used to manage transactions within a relational database. A transaction is a sequence of one or more SQL statements that are executed as a single unit of work. The BEGIN TRANSACTION statement marks the beginning of a transaction, and it is typically followed by…(Continue Reading)

SQL transactions are a crucial aspect of database management systems (DBMS) that ensure the integrity, consistency, and reliability of data. A transaction in SQL represents a sequence of one or more SQL statements that are executed as a single unit of work. The fundamental properties of a transaction, often referred to as ACID properties, are…(Continue Reading)

A Common Table Expression (CTE) is a temporary result set in a SELECT, INSERT, UPDATE, or DELETE statement that you can reference within the context of another SQL statement. CTEs provide a way to define complex queries and make SQL code more readable and modular. Here’s a breakdown of the key components and usage of…(Continue Reading)

Deleting duplicate rows in a database table is a common task in SQL, and it’s important for maintaining data integrity. Duplicate rows can occur for various reasons, such as data entry errors or system glitches. Here’s a guide on how to delete duplicate rows in SQL: Identifying Duplicate Rows Before deleting duplicate rows, you need…(Continue Reading)

In SQL, string matching refers to the process of finding and retrieving data from a database based on specific patterns or conditions within character strings. SQL provides various tools and functions to perform string matching operations, allowing users to search for specific substrings, patterns, or values within text columns. Here are some common techniques and…(Continue Reading)

In SQL Server, escaping apostrophes is an important consideration when dealing with string literals to ensure the proper handling of single quotes within the text. The single quote character is used to delimit string literals in SQL, so if your string contains a single quote, you need to escape it to avoid syntax errors or…(Continue Reading)