INFO 340 - June 2, 2004 - L19 Notes By: Prins ** No Lab on Friday ** D-Space (MIT) > Open source software platform that enables institutions to: - Capture and describe digital works - Distribute an institution's digital works over the web through a search and retrieval system - Preserve digital works over the long term separated into three layers Storage Layer Business Logic Layer Application Layer Final Examination Monday, June 7th, 2:30 - 4:20 Covers the Entire Course Today: Quick reminder of Key Topics > Systems - processes - inputs - outputs - entities - stakeholders - environment (is up to you to define) Three Key Ideas > Systems are hierarchal > Systems are nearly decomposable > System boundaries are arbitrary ** Development Life Cycle ** Define Design Develop ** OUR FOCUS IN CLASS ** Deploy Three Phases 1. Conceptual database design The process of constructing a model of the information used in the enterprise..... 2. Logical database design > The process of constructing a model of the information used in the enterprise based on a specific data model, but independent of a particular DBMS and other physical considerations > Key Idea: 'Translate' conceptual model into abstractions into target database 3. Physical database design > The process of producing a description of the implementation of teh database on secondary storage; - Base relations & Views - File organization - Indexes - Integrity constraints - Security measures > Key Idea: Performance & engineering issues > Big Issue: Keep data consistent and backed up Relational Model > Background - History, users, roles ... > DBMS Environment - Three-Level architecture, data models, data independence, functions, services, ... > The relational model - relations, keys, DML, DDL, SQL, integrity constraints, relational algebra. > Relational design - ER & EER modeling, connection traps, functional dependencies, normalization, ... IR vs Relational Database > IR Systems and Relational Database systems come from different cultures > They have traditionally solved different problems > How can we compare the two approaches? Exercise > What is the difference between IR and database systems? - Data structures used (inverted file vs trees) - Different Services - Storage of Data (data redundancy in indexes, but not well designed DB) ----- From Slide ----- (DB vs IR) - Matching (Exact Match vs Partial match, Best match) - Inference (Deduction vs Induction) - Model (Deterministic (know specification for right answers) vs Probabilistic (based on probability)) - Classification (Monotheistic vs Polytheistic) - Query Language (Artificial vs Natural) - Query Specification (Complete vs Incomplete) - Items wanted (Matching vs Relevant) - Error response (Sensitive vs Insensitive) ------------------------------------------------- oh. my. god. Becky, look at her butt! Its like one of those rappers' girlfriends. She must be a slut... OMGWTFBBQ Let's make a Baby! - Watch the Anchorman trailer @ quicktime.com heh, seen it on the big screen, funny stuff no, there is a new one :) from the 30th ooh... did either of you catch that video of that guy who stuck a camera on his car and sped it up, 9 hours of trip into 5 minutes? it was on slashdot yesterday I havent looked at the internet for a while lol blah blah blah kill me yeah I'm totally wrong, but will I speak up? hell no I think I might go home at the break... this is useless or not.