Data Models: Definition and concepts

• Definition of Data Model
• Concept of Data Modelling

INTRODUCTION TO DATA MODELLING

The main effort during the system development life cycle (SDLC) was to produce a set of programs that automates a business process. Processing was the key drivers for information systems, not the data or information. As the technology and complexity of system grew, methodologies and modelling techniques were invented to improve the quality of the deliverables and to ensure that inexperienced programmers could follow repeatable SDLC processes.

Definition of Data Modelling

Data Modelling is the process of structuring and organizing data. The data structures are then typically implemented in a database management system. In addition to defining and organising the data, data modelling may also impose constraints or limitations on data placed within the structure.

Managing large quantities of structure and unstructured data is a primary function of information systems. Data Models describe structured data for storage in data management system such as relational databases. They do not describe unstructured data such as word processing documents, email messages, pictures, digital audio and video.

Concept of Data Modelling

• Data modelling techniques and tools help to capture and translate complex system designs into easily understood representation of data flows and processes, creating a blueprint for construction and re-engineering.
• Data Models provide a structure for data used within information system by providing specific definition and format.
• Data Model shows the dataflow and logical interrelationship among different data elements.
• Compatibility of data can be achieved, if a data model is consistently used across the systems.

The term data model actually refers to two different things: a description of data structure and the way data are organized using Database Management System (DBMS).

Data Structure

A data model describes the structure of the data within a given domain and, by implication, the underlying structure of that domain itself.

Data Organisation

A data Model also describes how to organized data using a database management system.

EVALUATION

1. State the concepts of data modelling.
2. Describe the following; Data Structure and data Organization.

APPROACH IN DATA MODELLING

There are different approaches to data modelling, including;

Conceptual Data Modelling: The conceptual data modelling identifies the highest level relationships between different entities. This is the first step in organising the data requirements.

Logical Data Modelling: The logical Data modelling illustrates the specific entities, attribute and relationships involves in a business function. It serves as the basis for the creation of the physical data model.

Physical Data Modelling: The physical Data Modelling represents an application and database-specific implication of a logical data model and describes the physical means used to store data.

GENERAL EVALUATION

1. Explain the different approaches to data modelling.
2. Define data modelling.

READING ASSIGNMENT

Data Processing for Senior Secondary Education by HiiT Plc. Chapter One, page 55

WEEKEND ASSIGNMENT

Instruction: Choose the correct option from the ones lettered A to D

1. In the approach of data modeling ____ data modeling illustrate the specific entities, attribute and relationship involved in business function.
2. Conceptual Data Modeling  (b) Logical Data Modeling    (c) Flat data Modeling

(d)Physical Data Modeling

• The processing of structuring and organizing data is referred to as ______

(a)Data Structure        (b) Data Organization   (c) Data Manipulation   (d) Data Modeling

3.   The major concept for data modeling is to _____________________

      (a) Translate simple system design to complex representation of data

      (b) Translate complex system design to simple representation of data

      (c) Translate simple system design to simple representation of data

      (d) Translate complex system design to complex representation of data

• The term “Data Model” refers to two different things- data organization and ________
• Data Model (b) Data Processing      (c) Data Structure       (d) Data Organization
• The following are unstructured data Except
• Video          (b) email message         (c) Picture        (d) Database

SECTION B

1a.     Define data modeling.

• List three (3) approaches to Data modeling.

2.      State the major concept of Data Modeling.