study guide Flashcards
ad hoc query
A “spur-of-the-moment” question.
centralized database
A database located at a single site.
data
Raw facts, that is, facts that have not yet been processed to reveal their
meaning to the end user.
data anomaly
A data abnormality that exists when inconsistent changes to a
database have been made. For example, an employee moves, but the address
change is corrected in only one file and not across all files in the database.
data dependence
A data condition in which the data representation and
manipulation are dependent on the physical data storage characteristics.
data dictionary
A DBMS component that stores metadata—data about data.
Thus, the data dictionary contains the data definition as well as its characteristics and relationships. A data dictionary may also include data that are external to the DBMS. Also known as an information resource dictionary. See also active data dictionary, metadata, and passive data dictionary.
data inconsistency
A condition in which different versions of the same data yield different (inconsistent) results.
data independence
A condition that exists when data access is unaffected by changes in the physical data storage characteristics.
data integrity
In a relational database, refers to a condition in which the data in the database is in compliance with all entity and referential integrity constraints.
data management
A process that focuses on data collection, storage, and retrieval. Common data management functions include addition, deletion, modification, and listing.
data redundancy
A condition that exists when a data environment contains redundant (unnecessarily duplicated) data.
data warehouse
Bill Inmon, the acknowledged “father of the data warehouse,” defines the term as “an integrated, subject-oriented, time-variant, nonvolatile collection of data that provides support for decision making.”
database
A shared, integrated computer structure that houses a collection of related data. A database contains two types of data: end-user data (raw facts) and metadata. The metadata consist of data about data, that is, the data characteristics and relationships.
database design
The process that yields the description of the database structure. The database design process determines the database components. Database design is the second phase of the database life cycle.
database management system (DBMS)
Refers to the collection of programs that manages the database structure and controls access to the data stored in the database.
database system
An organization of components that defines and regulates the collection, storage, management, and use of data in a database environment.
desktop database
A single-user database that runs on a personal computer.
distributed database
A logically related database that is stored over two or
more physically independent sites.
enterprise database
The overall company data representation, which provides
support for present and expected future needs.
field
A character or group of characters (alphabetic or numeric) that defines a
characteristic of a person, place, or thing. For example, a person’s Social Security
number, address, phone number, and bank balance all constitute fields.
file
A named collection of related records.
information
The result of processing raw data to reveal its meaning.
Information consists of transformed data and facilitates decision making.
islands of information
A term used in the old-style file system environment to
refer to independent, often duplicated, and inconsistent data pools created and
managed by different organizational departments.