Managing Knowledge and Data
Difficulties
in Managing Data
ØAmount
of data increases exponentially
According to the annual survey of
the global digital output by International
Data Corporation, the total amount of global data
was expected to pass 1.2 zettabytes
ØData
are scattered and collected by many
individuals using various methods and devices
Difficulties
in Managing Data
ØData
come from many sources (e.g. Clickstream
data )
ØData
security, quality and integrity are critical. I
nformation
systems that do not communicate with each other can result in inconsistent data
ØData
degrades overtime
Examples: customers
move to a new address
employees are hired and
fired
ØData
rot:
problems with media on which the data are stored
Data Governance: an
approach to managing data across an entire organization.
Formal
sets of policies that are designed to ensure that the data are collected, handled
and protected in a certain, well-defined fashion
Master data management: a process/method that provides an
organizations with the ability to store, maintain, exchange and synchronize a
consistent, accurate and timely ‘single version of the truth’ for the organization's core master data
http://www.ncsi.gov.om/
Master data: a set of core data [customer, employee,
vendor, geographic location] that span all enterprise information systems.
Transaction data: data that are generated and captured by
operational systems
The
Database Approach
nDatabase management system (DBMS)
provides all users with access to all the data.
nDBMSs minimize the following problems:
nData redundancy:
The same data are stored in many places
nData isolation:
Applications cannot access data associated with other applications
nData inconsistency:
Various copies of the data do not agree.
nDBMSs maximize the following issues:
nData Security:
keeping
the organization’s data safe from theft, modification, and/or destruction.
nData integrity:
Data must meet constraints (e.g., student grade point averages cannot be
negative).
nData independence:
Applications and data are independent of one another. Applications and data are
not linked to each other, meaning that applications are able to access the same
data.
Bit:
a binary digit, or a “0” or a “1” - The smallest unit of
data a
computer can handle
Byte: eight bits and represents a single
character (e.g., a letter
number or symbol)
Field: is
a group of related characters
(e.g., student’s name, age
mobile number)
Record: a group of logically related fields
(e.g., student in a
university database)
Data model
a diagram that represents the entities in
the database and
their relationships
nEntity: a
person, place, thing, or event about which information is maintained. [A record
generally describes an entity]
nAttribute: a
particular characteristic of a particular entity
nPrimary
key (Key
field): a field that uniquely identifies a record, so
that it can be retrieved
and updated
nSecondary
Key
Entity-Relationship
Modeling
nDatabase designers plan and create the
database through a process called entity-relationship (ER) modeling.
nER
diagrams consists
of entities, attributes and relationships. [illustrating relationships between database entities]
nEntity
classes: groups
of entities of a certain type
nInstance: the
representation of a particular entity
nIdentifiers:
attributes
that are unique to that entity instance
§One-to-One [1:1
§ One-to-Many [1:M]
§ Many-to-Many [M:M]
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