DAT601 | Jesse Drummond | 2018

This week, Todd is transitioning from conceptual modeling into logical modeling, this lesson in particular is focusing on transitioning our conceptual models into logical models. We have been supplied with a workbook to follow along with as he explains various concepts to us, having some written work to reference to is sure a welcome addition. Todd is explaining how to resolve our preexisting relationships within our ERD models into the correct format for a logical model, different types of relationships require different methods. This is the first step in building & also validating out logical data models. The next step is validating relations using normalization which he has stated that he is not going to go into depth on until next Fridays lecture. Class Notes Logical Database Design One to Many relationship The primary key from the "one" side of the relationship is place sin the "many" relations as a foreign key. One to ...

Todd's lesson today begun with a brief of him telling us that we will be finishing up on conceptual modeling today and moving onto logical design next week, consequently we should also be finishing up our conceptual phase of our practice report. Union types is our first topic today, this describes the relationship between a single superclass/sublass with more than one other superclass. After he showed us an extensive diagram modeling a university structure in terms of it's people I have gained a greater understanding of the topic. The rest of the lesson is for our group to work on our conceptual model work. Class Notes Modeling with union types union type or category     represents a single superclass/subclass relationship with more than one superclass          subclass represents a collection of objects that is a a subset of the UNION of distinct entity types          attribute inheritance works more s...

Todd has started the lesson with a short explanation on generalized entities which is looks like we will be revisiting at a later date, then he has started to explain to us two different problems that can be encountered in ER models; Fan traps & chasm traps. The general take I am gathering is that linear built databases cant create errors in your database, generally a database would be build in a more circular fashion. Following this he has moved into discussing generalized & specialized entities, by modeling it with a picture on the board. The concept feels similar to the concept of OO programming with abstract classes and classes below that that then inherit the default attributes of the base class as well as adding their own unique requirements. His diagram on the board is demonstrating the way to model this form of "inheritance" in an ER model diagram, the highest level entity is called the "generalization" and the entities below it are called ...

Beginning this weeks second class Todd has provided an example document for our milestone one and is walking through it to help us understand the different types of tables he desires. Upon learning that this milestone is about 15 pages max I am feeling comfortable. After this he has continued with last weeks power point and explaining more conceptual database concepts in depth, including but not limited to: cardinality, weak vs strong entities, multiplicity constraints and so on. Below is some pictures from my teams brainstorming over our teams conceptual design done earlier today, nothing perfect but getting together to do this ignited some interesting conversation and I felt like we made progress in the end. Below are my class notes for today Cardinality     cardinality is the count of entities within the relationship Participation     specifies minimum number of relationship instances each entity can participate in     this is cal...

Todd started his lecture off by getting the point across that the ER diagram is supposed to understood by those not savvy to database terminology and symbols. Upon Todd going in depth about entities, the different types of attributes and keys I have not fully come to grip with understanding it all but I can feel the cogs turning in my brain upon his explanation of a variety of  real world examples. Todd glanced over some familiar concepts but some new stuff as well, the stuff that is sticking out to me that I will need to come to understand will be the different types of attributes as well as different types of keys. Along with this there are a couple new words that I have also popped up within my class notes. Cardinality is still a familiar concept from last years classes so this was easy to understand as he spoke about it, still yet to see if Todd will go into more depth on this although I'm not sure if its something that can offer much more depth considering its simplistic...

Today Todd talked to us for about 40 minutes on conceptual modeling and also showed a brief intro video into the entity relationship model. He also briefly mentioned at the start of the class that there are a wealth of resources on the moodle to digest if one would be so inclined to get ahead on course content before it comes up in class. After this conversation he sent us out in our groups to gather information from the queens garden park, nouns that we would then make into entities. This was all based on managing the park being our problem domain so all nouns gathered should be related to real things that the managers of the park would have responsibility over. After each group put their gathered potential entities into a google sheet it was clear many people came up with many different ideas, showing how such a problem domain can be approached and divided into multiple categories(none of them being necessarily wrong, as long as it covers everything required). Upon Todd then pl...

First class, this blog will include various notes recorded from classes, in no particular intended structure. Todd has spoken to us about two pioneering people in computer science, Peter Chen who invented Chens notation, which we will use in our production of conceptual models, Edgar Codd who is responsible for invented the relational database model which we will also be using. We have formed into a team for a practice project, Me, Patrick, Robin and Jake have banded together to form YEEZY SEASON APPROACHING. After the day was finished I have made a discord group for us, a google doc and a shared draw.io all to help us collaborate on the shared project together. Random Personal Notes Nouns probably should be entities Relations are usually represented by verbal or doing things Identify candidate keys and from then confirm a primary key, candidate keys allow you to have something to talk about with the people you are working with.