Chapter 1 Review
Explain the differences between data, information, and a database
1. Data are raw facts. 2. Information is processed data to reveal the meaning behind the facts. 3. A database is a computer structure for storing data in a shared, integrated fashion so that the data can be transformed into information as needed.
Main components of a database system?
1. Hardware 2. Software 3. People 4. Procedures 5. Data
Field
A character or a group of characters (numeric or alphanumeric) that describes a specific characteristic. A field may define a telephone number, a date, or other specific characteristics that the end user wants to keep track of.
What is the role of a DBMS, and what are its advantages?What are its disadvantages?
A collection of programs that manages the database structure and controls access to the data stored in the database. The DBMS receives all application requests and translates them into the complex operations required to fulfill those requests. Can cause data inconsistency
Data independence
A condition in which the programs that access data are not dependent on the data storage characteristics of the data. Systems that lack data independence are said to exhibit data dependence.
Record
A logically connected set of one or more fields that describes a person, place, event, or thing. For example, a CUSTOMER record may be composed of the fields CUST_NUMBER, CUST_LNAME, CUST_FNAME, CUST_INITIAL, CUST_ADDRESS, CUST_CITY, CUST_STATE, CUST_ZIPCODE, CUST_AREACODE, and CUST_PHONE
data inconsistency
Different versions of the same data appear in different places
Data redundancy
Exists when unnecessarily duplicated data are found in the database. Symptomatic of a (computer) file system, given its inability to represent and manage data relationships. Leads to poorly-designed database
Data
Raw facts from which the required information is derived. Data have little meaning unless they are grouped in a logical manner.
Metadata
Data about data. Data characteristics such as the data type (such as character or numeric) and the relationships that link the data.