it for business

1. What is an attribute? How is it related to an entity?

2. Define the term database. How is it different from a database management system?

3. What is a flat file?

4. How would you describe the traditional approach to data management? How does it differ from the database approach?

5. What is data modelling? What is its purpose? Briefly describe three commonly used data models.

6. What is a database schema, and what is its purpose?

7. Identify important characteristics in selecting a database management system.

8. What is the difference between a data definition language (DDL) and a data manipulation language (DML)?

9. What is a distributed database system?

10. What is a data warehouse, and how is it different from a traditional database used to support OLTP?

11. What is OLAP?

12. What is an ORDBMS? What kind of data can it handle?

13. Give an example of a visual database.

1. An entity is a generalised class of people, place, or thing (object) for which data is collected, stored, and maintained. An attribute is a characteristic of an entity. For example, employee number, last name, first name, hire date, and department number are attributes for an employee.

2. Databases are collections of integrated and related files. The DBMS is the software used to manipulate the database and provide an interface between the database and the user or application programs. A database management system is systems software that helps organise data for effective access and storage by multiple applications. A DBMS provides different users different views of the data (sub-schemas), avoids redundancy, encourages program independence, offers flexible access, and provides centralised control.

3. A flat file is a simple database program that has no relationship between its records and is often used to store and manipulate a single table or file.

4. In a database approach, a pool of related data is shared by multiple application programs. Rather than having separate data files, each application uses a collection of data that is either joined or related in the database.

5. A data model is a diagram of entities and their relationships. Data modelling usually involves understanding a specific business problem and analysing the data and information needed to deliver a solution. Data modelling allows database designers to show the logical relationships among data. The following table provides a summary of the different data models:

Database Model Characteristics

Hierarchical Data is organised in a top-down or inverted tree structure

Network An extension of the hierarchical model in which a member may

have many owners

Relational A model that organises data in tabular format with rows and columns

6. A database schema is a description of the entire database. It can be part of the database or a separate file. The DBMS can reference a schema to find where to access a particular piece of data in relation to another.

7. The important characteristics that should influence the selection of a database management system include: 1) database size – how large does the database need to be?; 2) number of concurrent users – how many users will access the database at any one time?; 3) performance issues – how fast does the database need to perform various operations?; 4) integration – does the database need to interact with other systems?; 5) features – what wizards, security, documentation systems and other pertinent tools come with the database?; 6) vendor – does the software supplier have a reliable history and a current stability?; and 7) cost – how much will the system cost in terms of purchase and operation?

8. The data definition language is a collection of instructions and commands which enables the database’s creator to describe the data and data relationships that are to be contained in schemas and sub-schemas (user views of the data). A data manipulation language includes the set of commands used to manipulate the data in a database. SQL is an example.

9. A distributed database system is one in which the physical data may be spread across several smaller databases connected via networks or telecommunication devices. Although in separate locations, the data may appear in a single unified schema.

10. A data warehouse is a relational database management system designed to specifically support management decision making. An online transaction processing (OLTP) system collects business data as it is generated. This data, while efficiently collected, is not ready for meaningful analysis. Instead, it must be rendered into a steady state before it can be used for decision making. The data in a warehouse is derived from the online transaction processing system data but only after it has been ‘cleaned up’. The data warehouse then manages the flow of this data to end user applications.

11. OLAP tools can tell users what happened in their business. Online analytical processing (OLAP) programs are used to store and deliver data warehouse information. The OLAP allows users to explore corporate data in new and innovative ways using multiple dimensions such as products, salespeople, or time. OLAP programs include spreadsheets, reporting and analysis tools, and custom applications.

12. An object-relational database management system (ORDBMS) is a DBMS capable of manipulating audio, video, and graphical data.

13. A visual database can be stored in some object-relational databases or special purpose database systems. Purdue University has developed an audio database and processing software to give singers a voice makeover. The database software can correct pitch errors and modify voice patterns to introduce vibrato and other voice characteristics. Drug companies often need the ability to analyse a large number of visual images from laboratories. The PetroView database and analysis tool allows petroleum engineers to analyse geographic information to help them determine where to drill for oil and gas.