er - INFS614, GMU, Lecture 2 1 Lecture 2 INFS614 INFS614,...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: INFS614, GMU, Lecture 2 1 Lecture 2 INFS614 INFS614, GMU, Lecture 2 2 Everyone have texts, Oracle accounts? Homework #1 is on the website. Lectures will follow text, but I may add some materials. Ill try to let you know when. You are responsible for both on tests. INFS614, GMU, Lecture 2 3 1) Requirements Analysis requirement requirement requirement requirement requirement requirement requirement requirement requirement requirement requirement requirement requirement requirement requirement 2) Conceptual Design (this lecture) 3) Schema Design 4) Physical Design R1 R2 R3 R1 R2 R3 Queries -> CREATE TABLE .... Feature not modeled: xxxxx Indices, Replication,... 4 Stages INFS614, GMU, Lecture 2 4 Stage 1: Requirements analysis lots of interviews! lots of listening/notetaking! what queries do your users ask? what reports do you produce? what are the integrity requirements for this info? hopefully this converges to one set of info reqs! but what if Bob wants weekly salary after taxes, and Jane wants monthly gross earnings? but what what if certain information systems already exist?? conflicts lead to an integration phase INFS614, GMU, Lecture 2 5 Stage 2: Conceptual Design (ER Model) what concepts (abstract data structures) satisfy these requirements? what integrity constraints apply? the ER (Entity-Relationship) Model is used to describe answers to these questions you will learn it in this lecture An aside data structures + integrity constraints = a data model (T/F)? INFS614, GMU, Lecture 2 6 An aside False! The ER model is 2/3 of a data model. no operations; insert, update, delete are fairly standard Anyone know UML? UML targets the broader enterprise, models application code well, but is not as good for DBMS-specific models Point #1: UML and ER have some overlap Point #2: ER doesnt capture operations (dont try) INFS614, GMU, Lecture 2 7 Stage 3: Schema Design the design of specific information objects computer applications, including user queries, can access Part 1: translation of ER diagrams into a relational schema (SQL DDL) we learn this next week Part 2: normalization (refinement) of a schema elegant process discussed in Chapter 15 we defer this to the end of the semester INFS614, GMU, Lecture 2 8 Stage 4: Physical Database Design now you consider operations! query mix (read-only? updates? how many tables involved?) workload (# of concurrent users? what are they doing?) access patterns (peak load? when can we install patches?) you decide on file structures, add indices, rewrite queries so the optimizer will work better, perhaps adjust your schema again, perhaps use replication things change, so you never stop doing this!...
View Full Document

This note was uploaded on 10/18/2009 for the course INFS 614 taught by Professor Staff during the Fall '08 term at George Mason.

Page1 / 58

er - INFS614, GMU, Lecture 2 1 Lecture 2 INFS614 INFS614,...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online