CIS 3050 Midterm #1
importance of data models
-A communication tool -Give an overall view of the database -Organize data for various users -Are an abstraction for the creation of good database.
business rules
-brief, precise, and unambiguous description of a policy, procedure, or principle, -enable defining the basic building blocks -describe main and distinguishing characteristics of the data
field
-character or group of characters that has a specific meaning -used to define and store data
database management system (dbms)
-collection of programs -manages the database structure -controls access to data stored in the database
sources of business rules
-company managers -policy makers -department managers -written documentation -interviews, surveys, or observations with end users
network models
-created to represent complex data relationships effectively -improved database performance and imposed a database standard -allows a record to have more than one parent -depicts both one-to-many and many-to-many relationships
dbms function
-data dictionary management -data storage management -data transformation and presentation -security management -multiuser access control -backup and recovery management -data integrity management
metadata
-data that describes the properties and context of user data -usually is separated from data itself (called structures)
database access languages
-query language -structured query language (sql)
data models
Simple representations of complex real-world data structures
attribute
characteristic of an entity
data dependence
data access changes when data storage characteristics change
distributed database
data is distributed across different sites
centralized database
data is located at a single site
data independence
data storage characteristics do not affect data access
structured query language
de facto query language and data access standard supported by the majority of DBMS vendors
relationship
describes an association among entities one-to-many many-to-many one-to-one
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
scheme data definition language
enables the database administrator to define the schema components
performance tuning
ensures efficient performance of the database in terms of storage and access speed
Nouns translate into
entities
data manipulation lanuage
environment in which data can be managed and is used to work with the data in the database
segments
equivalent of a file system's record type
unstructured data
exists in their original state
semi-structured data
processed to some extent
end-user data
raw facts of interest to end user
verbs translate into
relationships among entities
extensible markup language (xml)
represents data elements in textual format
tuple
rows
desktop database
runs on pc
islands of information
scattered data locations
constraint
set of rules to ensure data integrity
database
shared, integrated computer structure that stores a collection of end-user data and metadata
questions to identify the relationship type
-how many instances of B are related to one instance of A? -how many instances of A are related to one instance of B?
model
abstraction of a real world object or event
knowledge
-actionable information/wisdom
online analytical processing (olap)
tools for retrieving, processing and modeling data from the data warehouse
entity
unique and distinct object used to collect and store data
relational model
-Produced an automatic transmission database that replaced standard transmission databases -Based on a relation -Describes a precise set of data manipulation constructs
structural dependence
-access to a file is dependent on its structure -all file system programs are modified to conform to a new file structure
Entity names - Required to:
-be descriptive of the objects in the business environment -use terminology thats familiar to the user
advantages of dbms
-better data integration and less data inconsistency -increased end-user productivity -improved data sharing, security, access and decision making
hierarchical models
-developed to manage large amounts of data for complex manufacturing projects -represented by an upside down tree which contains segments -depicts a set of one-to-many relationships
SQL-Based Relational Database Application
-end user interface -collection of tables stored in the database -sql engine
proper naming
-facilitates communication between parties -promotes self-documentation
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 -poorly designed database causes difficult to trace errors
reasons for identifying and documenting business rules
-help standardize company's view of data -communications tool between users and designers -allow designer to understand business processes, develop appropriate relationship participation rules and constraints and create an accurate data model
disadvantages of dbms
-increased costs -management complexity -maintaining currency -vendor dependence -frequent upgrade/replacement cycles
role of dbms
-intermediary between the user and 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 user
information
-produced by processing raw data to reveal its meaning -requires context -bedrock of knowledge -should be accurate, relevant, and timely to enable good decision making
data
-raw facts -building blocks of info -data management
attribute name
-required to be descriptive of the data represented by the attribute
structured data
-results from formatting -structure is applied based on type of processing to be performed
current generation dbms software
-stores data structures, relationships between structures and access paths -defines, stores and manages all access paths and components
types of data anomaly
-update anomalies -insertion anomalies -deletion anomalies
relational database management system
A software program in which data is organized as a collection of tables, and relationships between tables are formed through a common field. -makes relational data model easier to understand and implement -hides the complexities of the relational model from the user -ex: oracle
data modeling
Iterative and progressive process of creating a specific data model for a determined problem domain
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
evolution of file system data processing
Manual File Systems -> Computerized File Systems -> File System Redux: Modern End User Productivity Tools
data quality
accuracy, validity, and timeliness of data
relationships are
bidirectional
business intelligence
captures and processes business data to generate information that support decision making
file
collection of related records
record
connected set of one or more fields that describes a person, place or thing
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
structural independence
file structure is changed without affecting the application's ability to access the data
query language
lets the user specify what much be done without having to specify how
relation/table
matrix composed of intersecting tuple and attribute
data warehouse
stores data in a format optimized for decision support
data dictionary
stores definitions of the data elements and their relationships
analytical database
stores historical data and business metrics used exclusively for tactical or strategic decision making
workgroup database
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
single-user database
supports only one user at a time
