Types of Schema in SQL - Imarticus Learning.pdf

In SQL (Structured Query Language), schema refers to the structure of the database, which includes tables, columns, data types, constraints, and relationships. There are several types of schemas in SQL that define how data is organized and stored within a database: Physical Schema: This schema defines how data is stored physically on a storage system, such as files, indexes, and tablespaces. It includes details like file organization, indexing strategy, and partitioning. Logical Schema: The logical schema defines the logical structure of the entire database, including tables, views, relationships, and constraints. It provides a high-level view of the database without specifying implementation details. Conceptual Schema: This schema presents the database structure from a business perspective, focusing on entities, attributes, and relationships between entities. It abstracts the database structure and serves as a blueprint for designing the database. External Schema: Also known as a subschema, an external schema defines how specific users or applications view the database. It includes a subset of the database schema, tailored to meet the requirements of different user groups or applications. Schema Object: In SQL, a schema object refers to database objects such as tables, views, indexes, sequences, procedures, functions, and packages. These objects are defined within schemas and help organize and access data efficiently. Understanding these types of schemas is crucial for SQL developers and database administrators as they design, manage, and optimize databases to meet organizational requirements efficiently. Each schema type plays a critical role in defining the structure, access, and management of data within the SQL database environment.