Database Systems Flashcards
What are the characteristics of data in today’s world?
Ubiquitous
Pervasive
What do databases make data?
They make data persistent and shareable in a secure way
What are databases?
They are specialized structures that allow computer-based systems to store, manage, and retrieve data very quickly
What does data consist of?
It consists of raw facts that are not yet processed to reveal its meaning to the end user
What does information result from?
It results from the processing of raw data to reveal its meaning
What is end-user data?
It is the raw facts of interest to the end user
What is metadata?
It is data about data, through which the end-user data is integrated and managed
What are database management systems?
They are a collection of programs that manage the database structure and controls access to data stored in the database
What does the database management system do for the user?
It enables data to be shared
Presents the en-user with an integrated view of data
Provides more efficient and effective data management
Improves sharing, security, integration, access, decision-making, productivity, etc
What does a single-user database do?
It supports one user at a time
What does a multiuser database do?
It supports multiple users at the same time
What is a centralized database?
It is data located at a single site
What is a distributed database?
It is data distributed across different sites
What is a cloud database?
It is a database that is created and maintained using cloud data services that provide defined performance measures for the database
What is a general-purpose database?
It contains a wide variety of data used in multiple disciplines
What is a discipline-specific database?
It is a database that contains data focused on specific subject areas
What is an operational database?
It is a database that is designed to support a company’s day-to-day operations
What is an analytical database?
It is a database that stores historical data and business metrics used exclusively for tactical or strategic decision making
What is a data warehouse?
It stores data obtained from the operational databases in a format optimized for decision support
What is online analytical processing?
They are tools for retrieving, processing, and modeling data from the data warehouse
What is unstructured data?
It is data that exists in its original (raw) state
What is structured data?
It is data that results from formatting
What is semistructured data?
It is data that is processed to some extent
What is an extensible markup language?
It represents data elements in textual format
Why is database design important?
It is important because the design of database structure will be used to store and manage end-user data
What does a well designed database do?
It facilitates data management and generates accurate and valuable information
What does a poorly designed database do?
It causes difficult-to-trace errors that may lead to poor decision making
What is a manual file system?
It is a systems of file folders and filing cabinets
What is a computerized file system?
It is a system created by a data processing specialist to track data and produce required reports
What is a file system redux?
It is a modern end-user productivity tool that includes spreadsheet programs such as excel
What are the problems with file system data processing?
Lengthy development times
Difficulty of getting quick answers
Complex system administration
Lack of security and limited data sharing
Extensive programming
What is structural dependence?
It is when a file is dependent on its own structure
All file system programs are modified to conform to a new file structure
What is structural independence?
It is when the file structure is changed without affecting the application’s ability to access the data
What is data dependence?
It is data that goes through access changes when the data storage characteristics change
What is data independence?
It is when the data storage characteristics are changed without affecting the program’s ability to access data
What is a logical data format?
It is the way a person views data within the context of a problem domain
What is the physical data format?
It is the way a computer “sees” data
What are the problems with file system data processing?
Unnecessarily storing the same data at different places:
Islands of information (i.e., scattered data locations)
Increases the probability of having different versions of the same data
Possible results of uncontrolled data redundancy:
Poor data security
Data inconsistency
Data-entry errors
Data integrity problems
Develop when not all of the required changes in the redundant data are made successfully:
Update anomalies
Insertion anomalies
Deletion anomalies
Where is logically related data stored?
It is stored in a single data repository
What is a database system?
It is the organization of components that define and regulate the collection, storage, management, and use of data within a database environment
What is hardware?
All of the system’s physical devices
What is software?
Operating system, DBMS, Application programs
What are do people do with data?
System administrators, database administrators, database designers, system analysts and programmers, end users
What are the last two factors of the database system environment
Procedures
Data
What is a data dictionary?
It stores definitions of data elements and their relationships
What is data performance managment?
Performance tuning ensures efficient performance
What is data transformation and presentation?
Data is formatted to conform to logical expectations
What is security management?
Enforces user security and data privacy
What is multiuser access control?
It is the sophisticated algorithms that ensure that multiple users can access the database concurrently without compromising its integrity
What is backup and recovery management?
Enables recovery of the database after a failure
What is data integrity management?
Minimizes redundancy and maximizes consistency
What is a query language?
Lets the user specify what must be done without having to specify how
What is a structured query language?
It is the de facto query language and data access standard supported by the majority of DBMS vendors
What are database communication interfaces?
Accept end-user requests via multiple, different network environments
What are the disadvantages of database systems?
Increased costs
Management complexity
Maintaining currency
Vendor dependence
Frequent upgrade/replacement cycles
