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CS 3630 Database Design and Implementation
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Assignment1 CS3630_A1.doc In folder J:\Public_html\CS363\NoteDir
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Incorrect or no name/section: -1
Assignment 2 Due Wednesday at Noon Incorrect File Name: -1 Incorrect or no name/section: -1
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Relational Database A collection of normalized tables/relations.
Database Design Relational Database A collection of normalized tables/relations. How many slides can be covered in one hour? All of them!
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The Three Level ANSI-SPARC Architecture
DBTG (Data Base Task Group) Appointed by the Conference on Data Systems and Languages in 1971 Two level approach SPARC: Standards Planning And Requirement Committee ANSI/X3/SPARC, 1975 Based on IBM's view For any database system Data Independence.
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The Three Level ANSI-SPARC Architecture
… External Level View 1 View 2 View 3 Conceptual schema Conceptual Level Internal schema Internal Level Database
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Phases of Database Design
Conceptual Database Design Understanding the data Logical Database Design Normalization Physical Database Design We ignore it.
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Conceptual Database Design
Users' views Understanding of the meaning of the data Common Sense Business rules Do not assume anything Students without any classes at UWP Classes without any students E-R Model Formal document to specify the requirements Entity and Relationship Independent of the target data model (relational, OO).
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Logical Database Design
Designer's view Based on the target data model Relational Normalization.
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Physical Database Design
Base relations and constraints File Organization and Storage Structure (Appendix C) Others.
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Conceptual Database Design E-R Model (Ch 11)
High level conceptual data model Top-Down approach Widely used but not the only model UML (Unified Modeling Language) Draw ER diagrams.
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Entity Types A group of objects with the same properties,
which are identified by the enterprise as having an independent existence. Similar to Class in OOP Class is an implementation of Entity.
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Physical Existence Branch Staff PropertyForRent Client Owner Customer
Product Supplier.
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Conceptual Existence Viewing Inspection Sale Work Experience.
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Entity Occurrence A uniquely identifiable object of an entity type.
Class and Object.
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Diagrammatic Representation of Entity Types
Rectangle The first letter of the entity name is upper case Branch Staff
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Relationship Types (Not Relation)
A set of meaningful associations among entity types. Branch Has Staff Staff Manages Branch Owner Owns PropertyForRent.
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Relationship Occurrence
A uniquely identifiable association, which includes one occurrence of each participating entity type Example Branch B003 has staff SG5 Owner O321 owns property P1045.
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Semantic Net for Relationship Occurrence
B003 SG5 r2 SG37 r3 B007 SA9 Branch Has Staff
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Diagrammatic Representation of Relationship Types
Directed line with the relationship name Has Branch Staff
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Degree of Relationship Type
The number of participating entity types in a relationship Binary Ternary Quaternary
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A Ternary Relationship
Registers Branch Staff Client
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A Quaternary Relationship
A solicitor arranges a bid on behalf of a buyer supported by a financial institute. Solicitor Arranges Buyer Bank Bid
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Recursive Relationship
A relationship type where the same entity type participates more than once in different roles. Staff (Supervisor) supervises Staff (Supervisee) Roles Supervisor Supervisee.
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Recursive Relationship
Supervises Supervisor Staff Supervisee
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Multiple Relationships between the Same Entity Types
Branch Has Staff (Staff Members) Staff (Manager) Manages Branch.
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Multiple Relationships between Entity Types
Manages Branch Staff Has
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Relationship or Entity?
Viewing As Entity in DreamHome example Could be a Relationship Client Views PropertyForRent It can be treated either way The final design will be the same.
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Attributes of an Entity Type
A property of an entity type or a relationship type. Similar to the fields of a class PropertyForRent propertyNo address (street, city, state, zipcode) type rooms rent . . .
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Attributes of a Relationship
Views Client PropertyForRent Views Date Comment
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Domain of Attribute The set of allowable values for one or more attributes PropertyForRent propertyNo: String (size) type: ‘Flat’, ‘House’ rooms: integer, rent: integer, 150 – 1000 . . .
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Simple and Composite Attribute
Simple attribute An attribute composed of a single component position salary GPA Composite attribute An attribute composed of multiple components name : firstName, lastName, middle address: street, city, state, zipcode DOB : year, month, day workExperience: organization, position, start, end.
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Single-valued and Multi-valued Attribute
Single-valued: An attribute that holds a single value for each occurrence of an entity type branchNo name DOB GPA The value could change from time to time, but one value at any given time. Multi-valued: An attribute that can hold multiple values for each occurrence of an entity type phoneNo studentMajor workExperience.
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Composite and Multi-valued Attribute
Composite attribute could be single-valued or multi-valued name: single-valued workExperience: multi-valued Multi-valued attribute could be simple or composite phoneNo: simple workExperience: composite.
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Composite and Multi-valued Attribute
Simple attribute could be single-valued or multi-valued salary: single-valued major: multi-valued Single-valued attribute could be simple or composite salary: simple DOB: composite.
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Derived Attribute An attribute that represents a value that is derivable from the values of a set of related attributes, not necessarily in the same entity type. Age Total Number of staff members Deposit of Lease is twice the rent.
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Required or Optional Attribute
Required Attributes studentID Name DOB . . . Optional Attributes phoneNo Major
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An Entity Type Example Staff staffNo
name : composite (first, last, middle) address : composite (street, city, state, zipcode) phoneNumber : multi-value salary workExperience: multi-value composite (organization, position, start, end) . . .
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A Relationship Example
Client Views PropertyForRent Date Comment
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