CIS 310 Ch. 1
Database management system (DBMS)
-Collection of programs -Manages the database structure -Controls access to data stored in the database
General-purpose databases
Contains a wide variety of data used in multiple disciplines
Discipline-specific databases
Contains data focused on specific subject areas
Cloud database
Created and maintained using cloud data services that provide defined performance measures for the database
Online analytical processing (OLAP)
Tools for retrieving, processing, and modeling data from the data warehouse
Business intelligence
Captures and processes business data to generate information that support decision making
DBMS Functions
-Data dictionary management >data dictionary -Data storage management >performance tuning -Data transformation and presentation >transforms entered data to conform to required data structures -Security management >enforces user security and data privacy -Multiuser access control >sophisticated algorithms ensure that multiple users can access the database concurrently without compromising its integrity -Backup and recovery management >enables recovery of the database after a failure -Data integrity management >minimizes redundancy and maximized consistency -Database access languages and application programming interfaces >query language >SQL -Database communication interfaces >accept end-user requests via multiple, different network environments
Structural dependence
Access to a file is dependent on its own structure -All file system programs are modified to conform to a new file structure
Metadata
Data about data, which the end-user data are integrated and managed
Data dependence
Data access changes when data storage characteristics change -Practical significance of it is the difference between logical and physical format
Distributed database
Data is distributed across different sites
Centralized database
Data is located at a single site
Data independence
Data storage characteristics is changed without affecting the program's ability to access the data
Structured Query Language (SQL)
De facto query language and data access standard supported by the majority of DBMS vendors
Operational database
Designed to support a company's day-to-day operations
Data anomaly
Develops when not all of the required changes in the redundant data are made successfully -Types: >update >insertion >deletion
Performance tuning
Ensures efficient performance of the database in terms of storage and access speed
Structural independence
File structure is changed without affecting the application's ability to access the data
Database design
Focuses on the design of the database structure that will be used to store and manage end-user data -Well-designed database >Facilitates data management >Generates accurate and valuable information -Poorly designed database causes difficult-to-trace errors
Unstructured data
It exists in their original state
Structured data
It results from formatting -Structure is applied based on type of processing to be performed
Query language
Lets the user specify what must be done without having to specify how
Database systems
Logically related data stored in a single logical data repository -Physically distributed among multiple storage facilities -Eliminates most of file system's problems -Current generation software: >Stores data structures, relationships between structures, and access paths >Defines, stores, and manages all access paths and components
Semistructured data
Processed to some extent
Extensible Markup Language (XML)
Represents data elements in textual format
DBMS
Role of the _____(acronym): -Intermediary between the user and the database -Enables data to be shared -Presents the end user with an integrated view of the data -Receives and translates application requests into operations required to fulfill the requests -Hides database's internal complexity from the application programs and users
Islands of information
Scattered data locations -Increases the probability of having different versions of the same data
Database
Shared, integrated computer structure that stores a collection of: -End-user data - Raw facts of interest to end user -Metadata: Data about data, which the end-user data are integrated and managed >Describe data characteristics and relationships
Data warehouse
Stores data in a format optimized for decision support
Analytical database
Stores historical data and business metrics used exclusively for tactical or strategic decision making -Data warehouse -Online analytical processing (OLAP)
Workgroup databases
Supports a small number of users or a specific department
Enterprise database
Supports many users across many departments
Multiuser database
Supports multiple users at the same time -Workgroup databases -Enterprise database
Single-user database
Supports one user at a time -Desktop database: Runs on PC
Evolution
_________ of file system data processing: -Manual File Systems (accomplished through a system of file folders and filing cabinets)--> -Computerized File Systems (data processing (DP) specialist: created a computer-based system that would track data and produce required reports)--> -File System Redux: Modern End-User Productivity Tools (includes spreadsheet programs such as Microsoft Excel)
Disadvantages
__________ of database systems: -increased costs -management complexity -maintaining currency -vendor dependence -frequent upgrade/replacement cycles
Advantages
__________ of the DBMS: -Better data integration and less data inconsistency -Increased end-user productivity -Improved: >Data sharing >Data security >Data access >Decision making -Data quality: Accuracy, validity, and timeliness of data
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