database systems Flashcards
raw facts, facts that have not yet been processed to reveal their meaning to the end user
data
the result of processing raw data to reveal its meaning
information
a shared, integrated computer structure that houses a collection of the: end-user data and metadata
database
a collection of programs that manages the database structure and controls access to the data stored in the database.
serves as the intermediary between the user and the database.
database management system (DBMS)
advantages of DBMS:
- improved data sharing
- improved data security
- better data integration
- minimized data inconsistency
- improved data access
- improved decision making
- increased end-user productivity
types of databases (12):
- single-user database
- desktop database
- multiuser database
- workgroup database
- enterprise database
- centralized database
- distributed database
- cloud database
- general-purpose database
- discipline-specific database
- operational database
- analytical database
a type of database that supports only one user at a time
single-user database
a single user database that runs on a personal computer
desktop database
a type of database that supports multiple users at the same time
multiuser database
a type of database that supports a relatively small number of users to a specific department within an organization
workgroup database
a type of database that is used by the entire organization
enterprise database
a type of database that supports data located at a single site
centralized database
a type of database that supports data distributed across several different sites
distributed database
a database that is created and maintained using cloud services
cloud database
a database that contains a wide variety of data used in multiple disciplines
general-purpose database
a type of database that contains data focused on specific subject areas
discipline-specific database
a type of database designed primarily to support a company’s day-to-day operations
operational database
a type of database focused primarily on storing historical data and business metrics used for tactical or strategic decision making
analytical database
refers to the activities that focus on the design of the database structure that will be used to store and manage end-user data
database design
reasons why database designs does not get the attention it deserves:
- insufficient specifications and/or poor logical data modeling
- not enough time in the development schedule
- too many changes occurring throughout the development cycle
- database design assigned to, or performed by novices
the first step in constructing a physical database should be transforming the logical design using best practices. the transformation consists of the following:
- transforming entities into tables
- transforming attributes into columns
- transforming domains into data types and constraints
- transforming relationships into primary and foreign keys
a critique of the file system method serves two major purposes:
- understanding the shortcomings of the file system enable you to understand the development of modern databases
- many of the problems are not unique to file systems
problems associated with file systems:
- lengthy development times
- difficulty of getting quick answers
- complex system administration
- lack of security and limited data sharing
- extensive programming
a data characteristic in which a change in the database schema affects data access, requiring changes in all access programs
structural dependence
a data characteristic in which changes in the database schema do not affect data access
structural independence
a data condition in which data representation and manipulation are dependent on the physical data storage characteristics
data dependence
a condition in which data access is unaffected by changes in the physical data storage characteristics
data independence
it exists when the same data is stored unnecessarily at different places
data redundancy
uncontrolled data redundancy sets the stage for the following:
- poor data security
- data inconsistency
- data-entry errors
- data integrity problems
a data abnormality in which inconsistent changes have been made to a database
data anomalies
a data anomaly develops when
_______
not all the required changes in the redundant data are made successfully
