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Management Information Systems

Notes 4. Because of .................................. data files, users face difficulty in getting information on
any ad hoc query that requires accessing data stored in more than one file.
5. Unlike a file processing system, data redundancy and data inconsistency in the database
system approach are ..................................

8.3 Database Models

A database model or database schema is the structure or format of a database, described in a
formal language supported by the database management system, In other words, a “database
model” is the application of a data model when used in conjunction with a database management
system.
Figure 8.3: Database Model

Different types of database models are:
1. Relational model
2. Object-oriented model

3. Hierarchical model
4. Network model
5. Flat file model
A data model is not just a way of structuring data: it also defines a set of operations that can be
performed on the data. The relational model, for example, defines operations such as select,
project, and join.

!

Caution Although these operations may not be explicit in a particular query language,
they provide the foundation on which a query language is built.

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