ch1 Flashcards
database
organized collection of logically related data
data
- stored objects that have meaning and importance
- two types: structured (table) and unstructure (media)
information
processed data to INCREASE KNOWLEDGE
metadata
- data that describes data. gives data meaning. like the headers of the table.
- includes: type, length, range, description
file processing systems
- like a file cabinet. each business function has their own different one and format. decentralized, some duplication of data.
disadvantages of file processing systems
- program data dependence
- data duplication
- limited data sharing
- lengthy development times
- excessive program maintenance
be careful not to put these in when developing your database
data models
graphical representation of nature and relationships of data
entity
NOUN. like an object in java.
attribute
data you are interested in keeping about entities
instance
each record of an entity
relational database
establish RELATIONSHIPS between entities by means of COMMON FIELDS. collection of tables that link to each other
database management systems (DBMS)
software system that enables use of database approach
data independence
separating metadata from applications that use the data. applications are not able to mess with metadata
redundant definition
able to be deleted without loss of function
user view
different users will have different views of same unified database
constraint
rule that cannot be violated by database users
data warehouse
combine historical data with new data to make bigger decisions
CASE tools
automated computer algorithms used to engineer data design
repository
restructure/recombine the data of other databases in a more meaningful manner to your task
application programs
allow you to easily use the data
system developers
design the database and applications
queries
commands against the database. like a command line. AKA ad-hoc querying - takes more technical skills
personal database
designed for one user. like your itunes lib. but they are difficult for others to use
workgroup
small group <25 users that work on same project
two-tier client server database
computers use centralized database. does introduce some new issues to think about. best for <100 users
mutitier client server database
heavy application logic is done “in the cloud” and data relayed to client tier. best for 100-1000 users
enterprise applications
scope is the entire business
ERP
enterprise resource planning. cross functional. allows easy syncronization of activities. best for >100 users
extranet
like the internet but only for allowed B2B customers
intranet
like the internet but used only by internal employees
hierarchial model
files organized like a tree
object oriented model
object classes and relationships between them. good for multimedia.
object relational model
hybrid between OO and relational models
multidimensional database
basis of data warehouse. view in cubes or star schema
enterprise data modeling
scope and general contents of databases are designed
compendium
brief summary of larger work; paraphrase
top up approach
try to meet organization goals; upper management
bottom up approach
features requested by users
systems development life cycle
methodology used to develop, maintain, and replace info systems
enterprise modeling
figure out what data you have and what you in proposed systems. pick the best one system.
conceptual data modeling
develop high level data model and then do a detailed plan with everything. same as conceptual schema
conceptual schema
detail structure of organizational data, important entities and attributes, NOT database design. high level so management can understand
logical database design
different format of conceptual schema. more technical but still somewhat independent from underlying technology
physical schema
specifications for how the logical schema will run on actual hardware. what will be on which servers?
database maintenance
longest part of life cycle. database will have to evolve according to needs
prototyping
iterative process, continual communication between users and analysts to converge on needs. try new things all the time?
agile software development
focus on individuals, not the computers
three schema architecture
1) external schema (user view)
2) conceptual schema (admin view)
3) internal schema (logical+physical schemas)
project
planned undertaking that has specific beginning and end
one to many relationship
one entity contains many of another entity
primary key
d
index
copy some data into another table for ease of access. example: index of all last names starting with L
systems development life cycle general steps
1) planning
2) analysis
3) design
4) implementation
5) maintenance
