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6. DBMS
Sources of data, Data file environment,
Database environment, Data models,Relevance of relational database
design in DSS
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Datasource
Datasource is a name given to theconnection set up to a database froma server.
A DataSource object is therepresentation of a data source inthe Java programming language. In
basic terms, a data source is afacility for storing data.
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Sources of Data
From another Database or storage location
From Web/ Network/ User/Groups
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Data File Environment
Storing and organizing files on HardDisk.
Low file Integrity.
Both Logically and Physicallyconnected files.
Less secured. Low sharing integrity.
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Database Environment
Storing and organizing files in aDatabase.
High file Integrity.
Logically connected Data Files,Physically scattered.
Very secure due to access rights. Highly sharable.
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Data Models
Flat model
Hierarchical model
Network model
Relational model
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Data Models
Object Relational model
Concept Oriented
Star Schema
http://en.wikipedia.org/wiki/File:Star-schema.pnghttp://en.wikipedia.org/wiki/File:Company_codm.gif8/9/2019 DSS & MIS 06 - DBMS
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ACID Property of a Database
Atomicity All-or-nothing rule
Consistency Referential Integrity
Isolation Concurrent transactions Durability Survival to system failure
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DBMS Concepts
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Keys in DBMS
Primary key
Foreign Key
Composite key Candidate key
Alternate Key
Secondary key
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DBMS Terminologies
Database
SQL
Data Warehouse Data marts
Entities
Relationships Attributes
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Relevance of RelationalDesign in DSS
Multidimensional problem solving
Critical queries
Referentially integrated inputs Data warehousing support
Data mart support
Sharability and scalability ofinformation
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DATABASENORMALIZATION
1NF, 2NF, 3NF, BCNF
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Normalization
ECODE DEPT DEPTHE
AD
PROJCOD
E
HOURS
E101 Systems E901 P27
P51P20
90
10160
E305 Sales E906 P27
P22
109
98
E508 Admin E908 P51
P27
NULL
72
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1NF
A table is said to be in 1NF if eachcell of the table contains preciselyone value.ECODE DEPT DEPTHEA
D
PROJCODE HOURS
E101 Systems E901 P27 90
E101 Systems E901 P51 101
E101 Systems E901 P20 60
E305 Sales E906 P27 109
E305 Sales E906 P22 98
E508 Admin E908 P51 NULL
E508 Admin E908 P27 72
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2NF
Every attribute in the row isfunctionally dependent on the wholekey.ECODE DEPT DEPTHEAD
E101 Systems E901
E305 Sales E906
E508 Admin E908
ECODE PROJCODE HOURS
E101 P27 90
E101 P51 101
E101 P20 60
E305 P27 109
E305 P22 98
E508 P51 NULL
E508 P27 72
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BCNF
ECODE NAME PROJCODE HOURS
E1 Veronica P2 48
E2 Anthony P5 100
E3 Mac P6 15
E4 Susan P2 250
E4 Susan P5 75E1 Veronica P5 40
ECODE NAME
E1 Veronica
E2 AnthonyE3 Mac
E4 Susan
ECODE PROJCODEHOURS
E1 P2 48E2 P5 100
E3 P6 15
E4 P2 250
E4 P5 75
E1 P5 40