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I know the Data Model is basically two types ER-Model and Relational Model & Database schema is also two type Physical and logical.
But I can not understand what is the difference between them based on their operation in DBMS?
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Database schema is a physical implementation of data model in a specific database management system. It includes all implementation details such as data types, constraints, foreign or primary keys.
A schema is a collection of database objects, including tables, views, indexes, and synonyms. There is a variety of ways of arranging schema objects in the schema models designed for data warehousing. One data warehouse schema model is a star schema.
A database model is a type of data model that determines the logical structure of a database. It fundamentally determines in which manner data can be stored, organized and manipulated. The most popular example of a database model is the relational model, which uses a table-based format.
Schema is of three types: Logical Schema, Physical Schema and view Schema.
A schema is a blueprint of the database which specifies what fields will be present and what would be their types. For example an employee table will have an employee_ID column represented by a string of 10 digits and an employee_Name column with a string of 45 characters.
Data model is a high level design which decides what can be present in the schema. It provides a database user with a conceptual framework in which we specify the database requirements of the database user and the structure of the database to fulfill these requirements.
A data model can, for example, be a relational model where the data will be organised in tables whereas the schema for this model would be the set of attributes and their corresponding domains.
References: Understanding the schema and Database System Concepts (H Korth and A Silberschatz)
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