Database Systems, Chapter 1

ad hoc query

A "spur-of-the-moment" question.

data dictionary

A DBMS component that stores metadata--data about data. The data dictionary contains data definitions as well as data characteristics and relationships. May also include data that is external to the DBMS.

data quality

A comprehensive approach to ensuring the accuracy, validity, and timeliness of data.

data independence

A condition in which data access is unaffected by changes in the physical data storage characteristics.

data inconsistency

A condition in which different versions of the same data yield different (inconsistent) results.

data anomaly

A data abnormality in which inconsistent changes have been made to a database. For example, an employee moves, but the address change is not corrected in all files in the database.

structural dependence

A data characteristic in which a change in the database schema affects data access, thus requiring changes in all access programs.

structural independence

A data characteristic in which changes in the database schema do not affect data access.

data dependence

A data condition in which data representation and manipulation are dependent on the physical data storage characteristics.

operational database

A database designed primarily to support a company's day-to-day operations. Also known as a transactional database, OLTP database, or production database.

analytical database

A database focused primarily on storing historical data and business metrics used for tactical or strategic decision making.

centralized database

A database located at a single site.

XML database

A database system that stores and manages semistructured XML data.

general-purpose database

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

discipline-specific database

A database that contains data focused on specific areas.

cloud database

A database that is created and maintained using cloud services, such as Microsoft Azure or Amason AWS.

multi-user database

A database that supports multiple concurrent users.

single-user database

A database that supports only one user at a time.

distributed database

A logically related database that is stored in two or more physically independent sites.

Extensible Markup Language (XML)

A metalanguage used to represent and manipulate data elements. Unlike other markup languages, XML permits the manipulation of a document's data elements.

workgroup database

A multiuser database that usually supports fewer than 50 users or is used for a specific department in an organization.

NoSQL

A new generation of database management systems that are not based on the traditional relational database model.

query language

A nonprocedural language that is used by a DBMS to manipulate its data. An example of a query language is SQL.

Structured Query Language (SQL)

A powerful and flexible relational database language composed of commands that enable users to create database and table structures, perform various types of data manipulation and data administration, and query the database to extract useful information.

data management

A process that focuses on data collection, storage, and retrieval. Common data management functions include addition, deletion, modification, and listing.

query

A question or task asked by an end user of a database in the form of SQL code. A specific request for data moanipulation issued by the end-user or the application to the DBMS.

business intelligence

A set of tools and processes used to capture, collect, integrate, store, and analyze data to support business decision making.

online analytical processing (OLAP)

A set of tools that provide advanced data analysis for retrieving, processing, and modeling data from the data warehouse.

database

A share, integrated computer structure that houses a collection of related data. A database contains two types of data: end-user data (raw facts) and metadata.

desktop database

A single-user database that runs on a personal computer.

data warehouse

A specialized database that stores historical and aggregated data in a format optimized for decision support.

manual file system

A system of holding a collection of data in file folders and filing cabinets.

performance tuning

Activities that make a database perform more efficiently in terms of storage and access speed.

database system

An organization of components that defines and regulates the collection, storage, management, and use of data in a database environment.

unstructured data

Data that exists n its original, raw state, that is, in the format in which it was collected.

semistructured data

Data that has already been processed to some extent.

structured data

Data that has been formatted to facilitate storage, use, and information generation.

basic file terminology

Data, Field, Record, File

Database Management Systems

Developed to address the file system's inherent weaknesses. •A single data repository •Promotes data sharing •Eliminates islands of information •Enforces data integrity •Eliminates redundancy •Promotes data security

data redundancy

Exists when the same data is stored unnecessarily at different places.

Data Management

File system data mgmt limitations are •that it requires extensive programming, •system administration can be complex and difficult, •making changes to existing structures is difficult, •security features are likely to be inadequate. •independent files tend to contain redundant data, •leading to problems of structural and data dependence.

data integrity

In a relational database, a condition in which the data in the database complies with all entity and referential integrity constraints. •Data is accurate •Data is verifiable

islands of information

In the old file system environment, pools of independent, often duplicated, and inconsistent data created and managed by different departments.

data

Raw facts, or facts that have not yet been processed to reveal their meaning to the end user.

production database

See operational database.

knowledge

The body of information ad facts about a specific subject. Knowledge implies familiarity, awareness, and understanding of information as it applies to an environment. A key characteristic is that new knowledge can be derived from old knowledge

query result set

The collection of data row returned by a query.

database management system (DBMS)

The collection of programs that manages the database structure and controls access to the data stored in the database.

enterprise database

The overall company data representation, which provides support for present and expected future needs.

data processing specialist

The person responsible for developing and managing a computerized file processing system.

database design

The process that yields the description of the database structure and determines the database components. The second phase of the Database Life Cycle.

information

The result of processing raw data to reveal its meaning. Information consists of transformed data and facilitates decision making.

physical data format

The way a computer "sees" (stores) data.

logical data format

The way a person views data within the context of a problem domain.

social media

Web and mobile technologies that enable "anywhere, anytime, always on" human interactions.

online transaction processing (OLTP) database

see operational database.

transactional database

see operational database.

Data

•Data consists of raw facts •Data is usually stored in a database.

Databases

•Database design defines the database structure. •DAtabases can be classified according to the number of users supported, where the data is located, the type of data stored, the intended data usage, and the degree to which the data is structured. •Databases evolved from manual and then computerized file systems.