Information Modeling By means of Entity Relationship (ER) Method Part – 4

Database Design with Information Modeling

The information modeling is one portion of the abstract design procedure. The other portion is known as the function modeling. The information modeling emphases on what information must be kept in the database on other hand the function modeling focus on by what means the information is handled. In the direction of placing this in the framework of the relational database, the information modeling is castoff to design the relational tables or relations. The functional modeling is castoff to handle the enquiries which will access as well as carry out activities on those tables or relations.

Information model is headed by planning in addition to analysis. The work dedicated to this phase is proportionate to the range of the database. The planning as well as analysis of a database which is envisioned to assist the requirements of a business will need maximum effort than one which is envisioned to assist a small workgroup.

The data required for creating the information modeling is collected in the course of the requirements analysis. Though informally portion of the information model phase is not considered by a number of procedures, in actuality the requirements analysis as well as the Entity Relationship (ER) diagram portion of the information modeling are completed at the same period.

Goals of Requirements Analysis

The aims of the requirements analysis are stated as follows:

• To decide the information requirements of the database in terms of basic objects or entities.

• To categorize as well as define the data about the objects or entities.

• To recognize as well as categorize the associations between the objects and entities.

• To define the kinds of transactions that will be implemented on the database as well as the communications among the transactions and the information.

• To recognize guidelines for controlling the reliability of the information.

The designer or designers works with the end users of a business to decide the information requirements of the database. Data desirable for the requirements analysis can be collected in more than a few methods, as described follows:

· Reviewing the present documents – This type of documents is comprised of present forms as well as reports, inscribed guiding principle, work explanations, individual descriptions, in addition to memorandums. A paper record is a decent method to become acquainted with the business or the action that an individual requires to complete the modeling.

· In-depth interview with the end users – This can be an amalgamation of separate individuals or cluster of individual interview. Clustered sessions should be kept under five (5) to six (6) individuals. Moreover, if possible, every member of the cluster should belong form the similar role in one particular meeting. Practice of a blackboard, casual diagrams and charts, as well as slide presentations are some useful methods to record data from the in-depth interviews.

· Reviewing the present computerized systems – When the business is already having an automatic computerized system, reviewing the system design stipulations as well as records are another helpful methods for collecting data.

The requirement analysis as well as information modeling is generally done at the same time. As data is gathered, information items are recognized as well as categorized as objects or entities, columns or attributes, or association; names are given and then they are demarcated by means of the terms which are known to or at least familiar to the end users. The objects or entities are then displayed as well as analyzed by means of an Entity Relationship (ER) diagram. The drawing can be studied by the designer as well as the end users to decide its comprehensiveness in addition to the accurateness. When the model is not accurate, it is altered, which occasionally needs extra data to be gathered. The analysis and alteration phase carry on till the model is certified as accurate. Three (3) facts to have in mind in the course of the requirements analysis are:

1. Have conversation with the end users regarding the information in real world relations. End users do not consider in terms of objects or entities, columns or attributes, as well as associations however they consider the real individuals, items, as well as events they deal in their everyday life.

2. Give time to study the fundamentals about the business as well as its doings which you want to model. Having a clear understanding about the procedures will make it stress free to construct the model.

3. The end users usually consider as well as observe the information in dissimilar ways according to their purpose in the business. For that reason, it is significant to talk with the maximum number of individuals when time allows doing so.

In the upcoming part we will be discussing the different Phases in Constructing the Information Model, how to Detect Information Entities as well as Relations and the Entities.