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are raw facts - building blocks of information - must be formatted for storage, processing, and presentation - are foundation of information, which is the bedrock of knowledge

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data

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Database Systems - Leaderboard

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Database Systems - Details

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1) Chapter 1 View

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33 questions

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Are raw facts - building blocks of information - must be formatted for storage, processing, and presentation - are foundation of information, which is the bedrock of knowledge

Data

- is the result of processing raw data to reveal meaning - Information requires context to reveal meaning - produces by processing data and is used to reveal meaning in data

Information

Focuses on proper generation, storage, and retrieval of data

Data Management

- shared, integrated computer structure that stores a collection of: 1) End-user Data: raw facts of interest to end user 2) Metadata: data about data

Database

- Provides description of data characteristics and relationships in data - Complements and expands value of data

Metadata

- collection of programs that manages the structure and controls access to data - the intermediary between the user and the database + Database structure stored as a file collection + Can only access files through the DBMS - DBMS enables data to be shared - DBMS integrates many users’ views of the data

Database Management System (DBMS)

~ Improved: - data sharing - data security - data access - decision-making ~ Better data integration ~ Minimized data inconsistency ~ Increased end-user productivity

Advantages of DBMS

-This database supports only one user at a time: Desktop database: single-user; runs on PC

Single-user database

-This database supports multiple users at the same time - Workgroup and enterprise databases

Multiuser database

Data located at a single site

Centralized database

Data distributed across several different sites

Distributed database

- supports a company’s day-to-day operations =>Transactional or production database

Operational database

Stores data used for tactical or strategic decisions

Data warehouse

-represents data elements in textual format ~>XML database supports semi-structured XML data

Extensible Markup Language (XML)

~> focuses on design of database structure used for end-user data Well-designed database: - Facilitates data management - Generates accurate and valuable information Poorly designed database: - Causes difficult-to-trace errors

Database design

- Widely used by business users - Users have become so adept at working with spreadsheets, they tend to use them to complete tasks for which spreadsheets are not appropriate – database substitute

Microsoft Excel

- Requires extensive programming - Cannot perform ad hoc queries - System administration is complex and difficult - Difficult to make changes to existing structures - Security features are likely to be inadequate

File System

- access to a file is dependent on its own structure - All file system programs must be modified to conform to a new structure

Structural dependence

- change file structure without affecting data access

Structural independence

Data access changes when data storage characteristics change

Data dependence

Data storage characteristics do not affect data access

Data independence

Same data stored unnecessarily in different places

Data Redundancy

Different and conflicting versions of same data occur at different places

Data inconsistency

Abnormalities when all changes in redundant data are not made correctly - Update anomalies - Insertion anomalies - Deletion anomalies

Data anomalies

Organizational structure promotes storage of same data in different locations

Islands of information

- consists of logically related data stored in a single logical data repository - May be physically distributed among multiple storage facilities - DBMS eliminates most of file system’s problems - Current generation stores data structures, relationships between structures, and access paths - Also defines, stores, and manages all access paths and components

Database Systems

Five major parts of a database system 1) Hardware 2) Software 3) People 4) Procedures 5) Data

Five major parts of a database system

All the system’s physical devices

Hardware

Three types of software required 1) Operating system software 2) DBMS software 3) Application programs and utility software

Software

- all users of the database system 1) System and database administrators 2) Database designers 3) Systems analysts and programmers 4) End users

People

Instructions and rules that govern the design and use of the database system

Procedures

The collection of facts stored in the database

Data

- Database systems are created and managed at different levels of complexity - Database solutions must be cost-effective as well as tactically and strategically effective - Database technology already in use affects selection of a database system

The Database System Environment