Ø   Data Model is a logical structure of Database . Ø   Data Models are fundamental entities to introduce abstraction in a DBMS. Ø   It provides the conceptual tools for describing the design of a database at each level of data abstraction. Ø   Data models define how data is connected to each other and how they are processed and stored inside the system. Ø   A Data Model in Database Management System (DBMS) is the concept of tools that are developed to summarize the description of the database.  Ø   Data Models provide us with a transparent picture of data which helps us in creating an actual database . It shows us from the design of the data to its proper implementation of data. Ø   It describes the design of database to reflect entities, attributes, relationship among data, constraints etc. Ø   It is the modelling of the data description, data semantics, and consistency constraints of the data. Ø   Therefore, there are following four data models used for understandin

  Ø   Database systems are made-up of complex data structures. To ease the user interaction with database, the developers hide internal irrelevant details from users. This process of hiding irrelevant details from user is called  data abstraction . Ø   The term “irrelevant” used here with respect to the user, it doesn’t mean that the hidden data is not relevant with regard to the whole database. It just means that the  user is not concerned about that data . Ø   For example:  When you are booking a train ticket, you are not concerned how data is processing at the back end when you click “book ticket”, what processes are happening when you are doing online payments.  You are just concerned about the message that pops up when your ticket is successfully booked . This doesn’t mean that the process happening at the back end is not relevant, it just means that you as a user are not concerned what is happening in the database. Ø   There are three levels of data abstraction Ø   Physic

  Ø   A Database Architecture is a representation of DBMS design . Ø   It helps to design, develop, implement, and maintain the database management system. Ø   A DBMS architecture allows dividing the database system into individual components that can be independently modified, changed, replaced, and altered. Ø   It also helps to understand the components of a database. Ø   A  Database   stores critical information and helps access data quickly and securely. Therefore, selecting the correct Architecture of DBMS helps in easy and efficient data management. Ø   We choose database architecture depending on several factors like the size of the database, number of users, and relationships between the users. Ø   The basic client/server architecture is used to deal with a large number of PCs, Web servers, Database servers and other components that are connected via networks. Ø   DBMS architecture depends upon how users are connected to the database to get their request done.