Database Systems - Chapter 1

Data

raw facts that have not been processed to reveal their meaning to end users, building blocks of information, used for data management

information

produced by processing raw data to reveal its meaning, requires context, used for knowledge, should be accurate, relevant, and timely to enable good decision making.

end-user data

raw facts of interest to end users

metadata

data about data, through white end-user data are integrated and managed. describe data characteristics and the set of relationships that links the data found within the database

Database management system (DBMS)

a collection of programs that manage the database structure and controls access to the data stored in the database.

DBMS

What acts as the intermediary between user and the database, allows data to be shared, presents the end user with an integrated view of the data, receives/translates application requests into operations required to fulfill the request, and hides database’s internal complexity from the application programs and users?

data inconsistency

different versions of the same data appear in different places

data quality

a comprehensive approach to promoting accuracy, validity, and timeliness of data

single-user database

database that supports one user at a time

desktop database

database that runs on pc

multiuser database

supports multiple users at the same time

workgroup databases

databases that support a small number of users or a specific department within an organization

enterprise database

supports many users across many departments

centralized databases

databases that store data in a single location, allowing for easier management and access by users.

distributed database

a database that is spread across multiple physical locations, allowing for data to be stored and accessed in various sites while maintaining a unified system.

cloud database

a database that is created and maintained using cloud data services that provide defined performance measures for the database, such as Amazon AWS

general-purpose database

database that contains a wide variety of data used in multiple disciplines

discipline-specific database

database that contains data focused on specific subject areas

operational database

designed to support a company’s day-to-day operations; aka an online transaction processing (OLTP) database, transactional database, or production database

analytical database

database that stores historical data and business metrics used exclusive for tactical or strategic decision making

data warehouse

stores data in a format optimized for decision support

online analytical processing front-end

tools for retrieving, processing, and modeling data from the data warehouse

business intelligence

captures and processes business data to generate information that supports decision making

unstructured data

data that exists in their original raw state

structured data

the results of formatting unstructured data to facilitate storage, use, and the generation of information. structure is applied based on the type of processing to be performed

semistructured data

data that has been process to some extent

extensible markup language (XML)

special language used to represent and manipulate data elements in a textual format, supports the storage and management of semistructured XML data

manual file systems

file systems accomplished through a system of file folders and filing cabinets

computerized file systems

file systems where a data processing specialist used a computer-based system that would track data and produce required reports

file system redux

file system that includes spreadsheet programs such as Microsoft Excel

field

a character or group of characters that has a specific meaning, used to define and store data

record

a logically connected set of one or more fields that describes a person, place, or thing

file

a collection of related records

file system data processing

what has the following cons: lengthy development times, difficulty of getting quick answers, complex system administration, lack of security and limited data sharing, extensive programming?

structural dependence

access to a file that is dependent on its structure, all file system programs are modified to conform to a new file structure

structural independence

file structure is changed without affecting the application’s ability to access the data

data dependence

when data access changes when data storage characteristics change

data independence

data storage characters can be changed without affecting the program’s ability to access the data

data redundancy

unnecessarily storing same data at different places

islands of information

scattered data locations, increases the probability of having different versions of the same data

data anomaly

develops when not all of the required changes in the redundant data are made successfully

update, insertions, deletion

what are the three types of data anamolies?

data dictionary

stores definitions of data elements and their relationships

performance tuning

ensures efficient performance of the database in terms of storage and access speed

query language

Lets the user specify what must be done without having to specify how

structured query language

De facto query language and data access standard supported by the majority of DBMS vendors

database communication interfaces

Accept end-user requests via multiple, different network environments

database systems

what comes with the disadvantaged of increased costs, management complexity, maintaining currency, vendor dependence, and frequent upgrade/replacement cycles