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What is a Database
A database is a collection of information stored in a computer in a systematic way,
such that a computer program can consult it to answer questions. The software used to
manage and query a database is known as a database management system (DBMS). The properties
of database systems are studied in information science.
"A carefully thought-out database design forms the foundation for future success. " |
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Traditional databases are organized by fields, records, and files. A field is a single piece of information; a record is one complete set of fields; and a file is a collection of records. For example, a telephone book is analogous to a file. It contains a list of records, each of which consists of three fields: name, address, and telephone number.
To access information from a database, you need a database management system (DBMS). This is a collection of programs that enables you to enter, organize, and select data in a database. |
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Data Modeling As Part of Database Design
An effective data model completely and accurately represents the data requirements of the end users.
It is simple enough to be understood by the end user yet detailed enough to be used by a database
designer to build the database. The model eliminates redundant data, it is independent of any hardware
and software constraints, and can be adapted to changing requirements with a minimum of effort.
The data model is one part of the conceptual design process. The other is the function model.
The data model focuses on what data should be stored in the database while the function model
deals with how the data is processed. To put this in the context of the relational database,
the data model is used to design the relational tables. The functional model is used to
design the queries that will access and perform operations on those tables.
Data modeling is preceeded by planning and analysis. The effort devoted to this stage
is proportional to the scope of the database. The planning and analysis of a database
intended to serve the needs of an enterprise will require more effort than one intended
to serve a small workgroup.
The information needed to build a data model is gathered during the requirments analysis.
Although not formally considered part of the data modeling stage by some methodologies,
in reality the requirements analysis and the ER diagramming part of the data model
are done at the same time.
Data modeling must be preceded by planning and analysis. Planning defines the goals of the database , explains why the goals are important, and sets out the path by which the goals will be reached. Analysis involves determining the requirements of the database. This is typically done by examining existing documentation and interviewing users. |
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Requirements Analysis
The requirements analysis is usually done at the same time as the data modeling.
As information is collected, data objects are identified and classified as either entities,
attributes, or relationship; assigned names; and, defined using terms familiar to the end-users.
The objects are then modeled and analysed using an ER diagram. The diagram can be reviewed by
the modeler and the end-users to determine its completeness and accuracy. If the model is not correct,
it is modified, which sometimes requires additional information to be collected. The review and edit
cycle continues until the model is certified as correct.
The goals of the requirements analysis are:
To determine the data requirements of the database in terms of primitive objects.
To classify and describe the information about these objects.
To identify and classify the relationships among the objects.
To determine the types of transactions that will be executed on the database and the interactions between the data and the transactions.
To identify rules governing the integrity of the data.
The modeler, or modelers, works with the end users of an organization to determine the data requirements of the database.
Information needed for the requirements analysis can be gathered in several ways.: - Review of existing documents - such documents include existing forms and reports, written guidelines, job descriptions, personal narratives, and memoranda.
Paper documentation is a good way to become familiar with the organization or activity you need to model.
- Interviews with end users - these can be a combination of individual or group meetings.
- Review of existing automated systems - if the organization already has an automated system,
review the system design specifications and documentation
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Identification of data objects and relationships
>Drafting the initial ER diagram with entities and relationships.
>Refining the ER diagram.
>Add key attributes to the diagram.
>Adding non-key attributes.
>Diagramming Generalization Hierarchies.
>Validating the model through normalization.
>Adding business and integrity rules to the Model.
In practice, model building is not a strict linear process. As noted above, the requirements analysis and the draft of the initial ER diagram often occur simultaneously. Refining and validating the diagram may uncover problems or missing information which require more information gathering and analysis
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Database Software Options
What type of database do you need? It's actually a simple matter of deciding what
features you need and choosing a product that meets your requirements and doesn't
cause too much pain in your pocketbook.
Desktop Databases
You're probably familiar with at least one desktop database product.
The market is dominated by brand-names like Microsoft Access and FileMaker Pro.
These products are relatively inexpensive and are great for single-user or
non-interactive web applications.
Server Databases
If you're planning a heavy-duty database application like an e-commerce site or a multiuser database, you're going to need to call on one of the big guns.
Server databases like MySQL, Microsoft SQL Server and Oracle provide real firepower but carry a correspondingly heavy pricetag
Nowadays, almost every database application calls for some kind of web interaction. Many people assume that if you're looking to publish your database on the Internet, you need to use a server database. That's not necessarily true -- a desktop database could (inexpensively!) meet your needs. |
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How we can Help?
SIT has rich expertise in wide spectrum of areas like
Database Design
,e-commerce, e-transformation, intranet/web applications, client-server technologies, systems integration, support & maintenance etc.
SIT has successfully completed a number of software projects across diverse platforms and technologies and satisfied clientele. Solutions are developed using proven methodologies for software development, re-engineering, conversion, porting and rapid application development.
SIT incorporates the element of Quality in every step of development process. Every project undergoes through rigid Quality controls and is audited as and when necessary, at various points. All this and more has enabled SIT to assure quality in its every produce |
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