CS122aSlides03

CS122aSlides03 - ICS122A / EECS116 Introduction to Data...

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1 ICS122A / EECS116 Introduction to Data Management Spring 2009 Prof. Mike Carey Bren School of ICS UC Irvine Slides based on previous CS122a lecture notes as well as  material borrowed from U-Wisconsin, Stanford, & Berkeley
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ICS122A/EECS116 Notes 02 2 Announcements HWs and projects HW#1 is now available (as of today) on Gradiance Hopefully everyone’s registered w/Gradiance now? Project (Part 1 of 4) will be out by Thursday at this time Discussion section meetings There will be a discussion session meeting this week Come with questions on HW and/or Project Part 1! We’ll see what time zone your TA Alex is on by then ( ) Lectures Any lingering questions / logistics from the last lecture? NOTE: Let’s keep this class interactive! (I appreciated the flow of questions last time – others are probably also wondering what you’re wondering, so keep asking ‘em…)
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ICS122A/EECS116 Notes 02 (II) 3 Review and Outline Database Design Process E/R Model Good design Principles Three primitive notions Entity sets Attributes Relationship sets Roles of entities in a relationship Constraints Constraints on entity sets key constraints domain constraints Constraints on relationship sets Cardinality constraints Participation constraints Referential integrity constraints Weak Entity Sets Multiple owner entity sets Multiway relationships Cardinality constraints over multiway relationships Ternary -> Binary relationships Superclass/subclass relationships Motivation Features Specification and generalization Different types Mutiple inheritance Aggregation (aggregate entity sets)
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ICS122A/EECS116 Notes 02 4 CAB can instead be represented as a weak entity set CAB’ (called a “ connecting entity set ”) The schema above, using binary relationships plus this weak entity set, now fully captures the ternary relationship branches accounts customers CAB’ Ternary Binary Relationships (III) customers accounts CAB branches C’ B’ A’ …. (we left off here) ….
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Notes 02 5 Previous mapping technique works for many-many-many relationships How can we convert many-many-1, many-1-1, and 1-1-1 ternary relationships into binary relationships? In general, this technique can always convert any ternary (or multiway) relationship into a collection of binary relationships w/o losing information However, the conversions can be complex and result in unnatural CAB CAB Ternary Binary Relationships (IV) branches branches customers accounts accounts
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ICS122A/EECS116 Notes 02 (II) 6 Subclass/Superclass Relationships (I) Motivation An ES may have some members (instances) with special attributes (properties) that are not associated with all ES members.
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This note was uploaded on 06/18/2009 for the course CS 122a taught by Professor Carey during the Spring '09 term at UC Irvine.

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CS122aSlides03 - ICS122A / EECS116 Introduction to Data...

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