Ch. 6 Text Flashcards
What are the issues with a traditional file system?
Systems tend to grow independently, without a company wide plan.
Some issues include:
1) Data Redundancy
2) Data Inconsistency
3) Program-Data Dependence
4) Lack of Flexibility
5) Poor Security
6) Lack of Data Sharing and Availability
What is data redundancy?
The presence of duplicate data in multiple data files so that the same data are stored in more than one place or location.
What is data inconsistency?
The same attribute has different values.
What is program-data dependence?
Refers to the coupling of data stored in files and the specific programs required to update and maintain those files such that changes in its program requires changes to the data
What is poor security?
Management may have no way of knowing who is accessing or even making changes to the organization’s data.
What is lack of data sharing and availability?
Pieces of information are in different files in different parts of the organization (not related to one another) making it virtually impossible for information to be shared or accessed in a timely manner.
What is a database management system (DBMS)?
Software that permits an organization to centralize data, manage them efficiently, and provide access to the stored data by application programs.
What are the benefits of a DBMS?
A DMBS reduces data redundancy and inconsistency by minimizing isolated files in which the same data are repeated.
Access and availability of information will be increased, and program development and maintenance costs reduced because users and programmers perform ad hoc queries of the database for many simple questions without having to write complicated programs.
Data sharing throughout the organization is easier because the data are presented to users as being in a single location rather than fragmented in many different systems and files.
What is a data dictionary?
An automated or manual file that stores definitions of data elements and their characteristics.
For larger companies, data dictionaries may capture additional information such as usage, ownership, authorization, security, and the individuals, business functions, programs, and reports that use each data element.
What are queries?
A request for data results from your database or for action on the data, or for both.
A query can give you an answer to a simple question, perform calculations, combine data from different tables, add, change, or delete data from a database.
What is SQL?
The most prominent data manipulation language (used for relational database management systems).
This is used to add, change, delete, and retrieve data in the database.
This language contains commands that permit end users and programming specialists to extract data from the database to satisfy information requests and develop applications.
What is a data warehouse?
A database that stores current and historical data of potential interest to decision makers throughout the company.
The data warehouse makes the data available for anyone to access as needed, but the data cannot be altered.
