5.2 database approach Flashcards
file management environment
original old timey way of data management
data file
collection of logically related records
what is the benefit of using a database?
eliminates many problems of old file maangemt systems
-> all users can access to al of the data
->reduce DATA REDUNDANCY!
->reduce DATA ISOLATION!
-> reduce DATA INCONSISTENCY!
Data redundancy
the same data are stored in multiple locations
Data Isolation
applications cant access data associated with other applications
Data inconsistency
various copies of the data do not agree
benefits of database systems?
1) data security
2) data integrity
3) data independance
data security- important to the database
since all the data is in one place, we need A LOT OF DATA SECURITY!!!!
data integrity- important to the database
data must meet certain constraints- there are no alphabetic characters in the sin fieldd
data independance- importnt to the database
applications and data are independant of one another- that is, applications and data are not linked to each othe. so all applications are able to access the same data
The Data Hierarchy
bits -> databases
What is a bit
BINARY DIGIT, represents the smallest unit of data a computer can proccess
Binary
means that a bit consist only of a 0 or 1
What is a group of eight bits
byte
Byte
-8 bits, represents asingle character
Examples of a byte
a letter, a number, or a symbol
what is a collection of bytes calles
a FIELD (that is a small group of words, word, or an ID number)
What is a Field
describes an entity, can contain data other than text and numbers
(Collection of bytes)
What is a logical grouping of related fields called
a record
what is a recrod
collection of related fields
EX: the apple tunes store is the record, the songs are fields
What is a logical grouping of related records called?
a data file or a TABLE
WHAT is a data file/ table
related records
what is a logical grouping of related files
database
bit, byte, field, record, table, database
this is the order
what is a database management system DBMs
set of programs that gives users the tools to create and maange a database
what
what does managing a database mean
process of adding delecting accessing modifying and analyzing data !!
how can an org acccess the data in a database
using query and reporting tools that are part of the dbms
example of a database architetctures
relational database model is popular and easy to use
EX: microsoft accesss and oracle
what is the relational database model
-Tables usually have rows and columns
-the relational database contains tables!! and connects tables!
why is the relational database model not one big table/ flat file
because this would involve too much data redundancy (different funcitonal areas needing the same info)
how is data in the relational database organized
with the data model
what is an entity
a person. place, a thing, or an event
customer, employe, product, invoice, store
which level of the data hierarchy is the entity?
records are usually entities
what is an instance of an entity?
each row in an entity table! specific, unique representation of the entity
this would be the numeric data NOT THE ATTRIBUTE!!
what is each characterisitc of an entity called
the attribute!!!
EX: Customer entity
Age, address, name, preference
What is a primary key, and why is it important?
every record (entity) in the database must contain at least one field that identifies that record (entity)
UNIQUE IDENTIFIER!! THIS IS THE PRIMARY KEY
what is a secondary key
another field that has some identify ingo about an entity, but does not identify the record completely!!!
ex: instead of the students UCID, you use their major
Foreign key
a field or sereral fields that like one table to another table@@
what is big data
huge quantitis of data
(diverse, high volume, high velocity)
-unstructured
EX: (EMAIL MESSAGES, VIDEOS, IMAGES, AUDIO FIELDS)
strucutred data
highly organized in fixed field in a relational database
4 categories of big data
1) traditional enterprise data
2) machine/sensor generated data
3) social data (blogs/feedback)
4)images captured by machines
3 characteristics of big data
VOLUME: lots of data (tradiitonal=invoices, non traditional=clicks)
VELOCITY: flowing at a high rate
VARIETY: more and more TYPES OF DATA
