SQL databases are relational databases that use SQL (Structured Query Language) for creating, modifying, and querying data stored in tables. SQL databases are widely used for storing and managing large amounts of structured data, making them a cornerstone of many web applications and enterprise systems. They are known for their scalability, reliability, and ability to […]
Category Archives: SQL
SQL Injection is a security vulnerability that can occur in a database-driven web application. It is one of the most common web application security risks and occurs when user-supplied data is used in an SQL query without proper validation and escaping. This can lead to an attacker gaining access to sensitive information stored in the […]
SQL views are virtual tables that allow you to access data from one or more tables in a database as if they were a single table. Views provide a way to simplify complex data structures and improve the readability and security of your queries. Creating a View A view is created using the CREATE VIEW […]
In SQL, the DATE data type is used to store date values. Dates are one of the most commonly used data types in SQL and are used to record events, transactions, and other time-related information. In this article, we will look at the basics of working with dates in SQL. Inserting Dates To insert a […]
In SQL, an AUTO INCREMENT field is a type of data field that is automatically assigned a unique value whenever a new record is inserted into a table. This feature is especially useful when dealing with primary keys, as it ensures that each record has a unique identifier that can be used to reference it […]
A SQL index is a database object that provides fast access to the rows of a table. It allows the database management system to quickly retrieve the required data from the table without having to scan through all the rows. An index is essentially a copy of a subset of the data in a table, […]
A SQL DEFAULT constraint is used to provide a default value for a column in a table. This value is inserted into the column if no value is specified when a new row is added to the table. The DEFAULT constraint is useful for providing a default value for columns that do not require a […]
SQL CHECK Constraint is an important aspect of relational database management systems like MySQL, SQL Server, Oracle, and MS Access. It is used to impose restrictions on the data that can be inserted into a table, thereby ensuring data integrity and consistency. What is SQL CHECK Constraint? A CHECK constraint is a type of validation […]
A SQL FOREIGN KEY constraint is a database constraint in SQL that creates a relationship between two tables. It is used to enforce referential integrity in a database, ensuring that data entered into one table is related to data in another table. The FOREIGN KEY constraint is used to prevent the insertion of data into […]
The SQL PRIMARY KEY constraint is a database constraint in SQL that ensures the uniqueness and non-duplication of values within a column or set of columns. It is an important tool in ensuring the accuracy and consistency of data within a database and is used to prevent data redundancy. In addition, it is also used […]