Database Introduction

INSY 472 : File management and Database Systems

Traditional File processing ●

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This is a scenario where data is organized, stored and processed in independent files. Data is dependent and tied to the application that created it. The file processing approach became too cumbersome, costly and inflexible and had the following major problems: ●

Data Redundancy –Independent files contain a lot of duplicated data due to the same data being stored in different locations. This caused update

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Lack of Data Integration – having data in independent files made it difficult to satisfy ad hoc requests for data from multiple files. Retrieval required special applications that made it costly, time consuming and difficult. Data Dependence – applications stored files in a specific format. Thus changes to this format meant a change had to be done to the applications referencing the data. Lack of data integrity and Standardization – due to the multiple applications referencing the data it was possible for data to be referenced differently in different applications. Also integrity ( accuracy and completeness) of data was hard to achieve because there was no control over the

The Database Management Approach ●

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The database management approach was conceived as a solution to problems with the file processing approach. The database management approach consolidates data which was in separate files into a database that can be accessed by different programs. The database is managed by a DBMS ( database management system) that helps in the creation, interrogation and maintenance of the database.

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Database development involves defining and organizing the content and structure of the data needed to build a database. Database interrogation is the process of asking the database for information using a query or a report. Queries are ad hoc requests for specific information from a database. Reports are requests for predefined data from a database. Database maintenance is the process of changing the state of the database by carrying out a transaction on the database ( transactions have to conform to ACID properties).

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Types of databases include : ●

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Operational Databases ( subject area databases, transaction or production databases) this store detailed data needed to support the business processes and operations of a company. Distributed Databases this are databases or parts of databases that are replicated at various locations. External Databases are databases found outside the boundaries of an organization and can be accessed for free or for a fee. Hypermedia Databases are databases consisting of hyperlinked pages of multimedia ( text, graphics, images, video clips and audio)

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Data warehousing – a data warehouse stores data that has been extracted from various operational, external and other databases of an organization. It is a source of cleaned, transformed and catalogued data that can be used for data mining, online analytical processing and other forms of business analysis, market research and decision support. Data marts are subsets of a data warehouse that focus on a specific aspect of the organization.

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Data mining – this is where data in a data warehouse is analyzed to reveal hidden patterns and trends in historical business activity. Data mining can be used to discover new correlations, patterns and trends in vast amounts of business data. Data mining can be used to: ●

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Perform market-basket analysis to identify new product bundles. Find root causes of quality or manufacturing problems.

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Acquire new and retain old customers.

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Cross-sell to existing customers.