Relational database concepts

A relational database is a type of database management system that organizes and stores data in tables. These tables are related to each other through defined relationships, such as primary keys and foreign keys, enabling efficient data retrieval and manipulation.

A primary key is a column or a set of columns in a table that uniquely identifies each row. It ensures that each row in the table has a unique identifier, which is essential for data integrity and efficient data retrieval.

A foreign key is a column or a set of columns in a table that refers to the primary key of another table. It establishes a relationship between two tables by enforcing referential integrity and allowing data to be shared and connected between them.

Normalization is the process of structuring and organizing data in a relational database to eliminate data redundancy and minimize data dependency. It involves breaking down larger tables into smaller ones and establishing relationships between them to improve data integrity and flexibility.

An index in a relational database is a data structure that improves the speed of data retrieval operations, such as searching, sorting, and joining tables. It allows the database engine to locate data more efficiently by creating a separate data structure based on selected columns.

A one-to-many relationship in a relational database occurs when each record in one table can be associated with multiple records in another table. It is the most common type of relationship, often represented by a foreign key in the "many" side table.

A many-to-many relationship in a relational database occurs when multiple records in one table can be associated with multiple records in another table. It requires a junction table to connect the related records, typically using the primary keys of both tables.

Referential integrity in a relational database refers to the consistency and correctness of the data relationships between tables. It ensures that foreign key values in one table match the primary key values in another table, preventing orphaned records and maintaining data integrity.

A view in a relational database is a virtual table that is derived from the data in one or more underlying tables. It acts as a saved SQL query that can be treated and used like a table, providing a convenient way to present specific subsets of data.

A transaction in a relational database is a unit of work that consists of multiple database operations, such as inserting, updating, or deleting records. It ensures that all the operations are executed as a single, atomic unit, maintaining data consistency and allowing for rollback in case of errors.