Tag: Trigger


  • A foreign key is a column (or a set of columns) in one table that establishes a relationship with the primary key of another table, ensuring referential integrity between the two tables. A foreign key is used to enforce relationships between tables, ensuring that values in the foreign key column match values in the primary…

  • A primary key is a unique identifier for each record in a database table, ensuring that no two rows have the same value in the specified column(s) and preventing duplicate entries. A primary key ensures that each row in a table is uniquely identifiable. It must satisfy two conditions: Primary keys can be single-column keys…

  • A row in a database table represents a single record or entry containing values for each column, maintaining data consistency within the table. A row, also known as a record or tuple, contains actual data stored in the database. Each row in a table corresponds to a real-world entity. For example, in a Students table,…

  • A column in a database table represents a specific attribute or field of an entity, defining the type of data it can store and ensuring uniformity across all rows in the table. A column specifies the type of data that can be stored in a table. Each column has a unique name and a defined…

  • A table in a database is a structured collection of related data organized into rows and columns, where each row represents a unique record and each column represents an attribute of the data. A table is the fundamental building block of a relational database. It consists of multiple columns (fields) that define the type of…

  • SQL (Structured Query Language) is a standard programming language used for managing, querying, and manipulating relational databases by performing operations such as retrieval, insertion, updating, and deletion of data. SQL is the most widely used language for interacting with relational databases. It is composed of different types of commands: SQL ensures data consistency and enables…

  • An Entity-Relationship Diagram (ERD) is a visual representation of data entities, their attributes, and the relationships between them in a database system, aiding in logical database design. An ERD is a conceptual blueprint that helps database designers plan how data will be structured before implementing a database. It consists of entities (representing tables), attributes (representing…

  • A relational database follows the principles of relational algebra and is based on a structured schema. The data is stored in tables, where each table consists of unique rows, and each row has attributes that define the characteristics of the stored data. The relational model was introduced by Edgar F. Codd in 1970 and has…

  • A DBMS acts as an interface between users and the database, allowing them to store, retrieve, update, and delete data using structured queries. It provides mechanisms for managing concurrent access, ensuring data consistency, and enforcing security constraints. Examples of DBMS include MySQL, PostgreSQL, Oracle, and Microsoft SQL Server. A Database Management System (DBMS) is a…

  • A database is a structured collection of data that is stored and managed electronically. Databases are essential for storing large volumes of information and enabling efficient retrieval, modification, and management of this data. They can range from simple systems (such as a spreadsheet) to complex systems used by enterprises, such as financial databases or customer…