What do you mean by database scheme. Explain with example.
Database Management System
Computer Science Engineering
528
Angelina
A database schema refers to the logical structure or design of a database. It defines how the data is organized, the relationships between different entities, and the constraints and rules that govern the data. In simple terms, a database schema acts as a blueprint for a database.
A database schema consists of tables, columns, data types, relationships, and other specifications that define the structure and characteristics of the database. It provides a framework for storing and retrieving data in a structured manner.
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Let's consider a simple example of a database schema for an online bookstore. The schema may include the following components:
Tables: The schema may define several tables, such as "Books," "Authors," and "Customers." Each table represents a different entity or concept in the database.
\Columns: Each table consists of columns that define the attributes or properties of the entity. For example, the "Books" table may have columns like "BookID," "Title," "AuthorID," "Price," and "PublicationDate."
Data Types: Each column has a data type that specifies the kind of data it can store. For instance, the "BookID" column may have a data type of integer, the "Title" column may have a data type of string, and the "Price" column may have a data type of decimal.
Relationships: The schema establishes relationships between tables. In this example, the "Books" table may have a foreign key relationship with the "Authors" table. The "AuthorID" column in the "Books" table would refer to the primary key in the "Authors" table, linking the two tables together.
Constraints: The schema can include constraints that enforce rules on the data. For instance, the schema may specify that the "Price" column should only accept positive values or that the "Title" column cannot be empty.
By defining this schema, the database can ensure that the data is organized in a structured manner, and it provides a framework for performing operations like inserting, updating, and retrieving data. It also helps maintain data integrity and consistency within the database.
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