Important Computer Awareness Materials for IBPS Exams 2017 (Day-10)

Important Computer Awareness for IBPS Exams 2017 (Day-10) – DBMS Part-10:

Dear Readers, IBPS Exams are approaching shortly, we all knew that Computer Awareness is one of the important section, which will help you to increase your score easily.



Many of our followers were asking us to provide Important Computer Awareness Notes along with the model questions, here we have planned to provide the Topic wise Important Computer Awareness Materials on Daily basis, and also we will provide MCQs based on these topics daily. Kindly follow us regularly and make use of it.

2. Physical Data Models:

Physical data model represents how the model will be built in the database. A physical database model shows all table structures, including column name, column data type, column constraints, primary key, foreign key, and relationships between tables. Features of a physical data model include:

Specification all tables and columns.

·         Foreign keys are used to identify relationships between tables.

·         Denormalization may occur based on user requirements.

·         Physical considerations may cause the physical data model to be quite different from the logical data model.

·         Physical data model will be different for different RDBMS. For example, data type for a column may be different between MySQL and SQL Server.

3. Record based data models:

(a) Hierarchical data models:

A hierarchical database model is a data model in which the data is organized into a tree-like structure. The data is stored as records which are connected to one another through links. A record is a collection of fields, with each field containing only one value. The entity type of a record defines which fields the record contains.

(b) Network Data Models:

The network model is a database model conceived as a flexible way of representing objects and their relationships. Its distinguishing feature is that the schema, viewed as a graph in which object types are nodes and relationship types are arcs, is not restricted to being a hierarchy or lattice.

The Network model replaces the hierarchical tree with a graph thus allowing more general connections among the nodes. The main difference of the network model from the hierarchical model, is its ability to handle many to many (N:N) relations. In other words, it allows a record to have more than one parent.

(c) Relational Data Models:

 Where all data is represented in terms of tuples, grouped into relations. A database organized in terms of the relational model is a relational database.

The purpose of the relational model is to provide a declarative method for specifying data and queries: users directly state what information the database contains and what information they want from it, and let the database management system software take care of describing data structures for storing the data and retrieval procedures for answering queries.

ONE LINER:

1. In which model data is stored in computer memory?

    Physical Data Model

2. In which Data model parent can have n- children?

    Hierarchical data model

3. One to many is for:

    Hierarchical data model

4. Which is designed to address the drawbacks of hierarchical model?

     Network data model

5. Tables, relations, keys, attributes are established in:

     Relational data model

        

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