Today’s lecture reviewed the high-level conceptual language of ER diagrams and the more concrete structures of the relational model; followed by some recipes for translating from the first into the second. This isn’t always an exact match, and for any particular ER diagram we might go back to its original scenario description to decide how to best represent it as a relational model. Even so, this kind of step-by-step staging towards a fully formal representation is an effective route to capturing the subtleties of real-world systems.
Continue reading Lecture 4: From ER Diagrams to Relational Models
The first set of tutorial exercises are now online. Click on the thumbnail to the right to download them. Please read the information box on the opening page before you start work on these.
Continue reading Tutorial Exercises
Today’s lecture expanded on last week’s material on Entity-Relationship modelling, and then set out the basic elements of the Relational Model for structured data. While ER diagrams provide a conceptual language for describing things as they are, and have applications outside databases for general organisation and management, the relational model is explicitly intended as a mathematically precise scheme for the computer-assisted creation and querying of large datasets.
Continue reading Lecture 3: The Relational Model
The slides for each Inf1-DA lecture are available in advance from the Lectures web page. On the day of the lecture you’ll see them marked “(Handout)” as that’s the version in the 3-up printed sheets. After the lecture itself I put up a blog post with a copy of the slides as displayed — sometimes that has a few more bits and pieces included.
Sometimes this means the page changes faster than web and browser caches expect: if you can’t get the slides for the day, try refreshing.
Link: List of lectures so far
Today’s lecture opened the topic of structured data with an introduction to Entity-Relationship Modelling and the graphical language of ER diagrams. This language is important for planning and structuring databases, bridging the gap between informal conceptual design and the logical precision required for machine implementation.
Continue reading Lecture 2: Entities and Relationships
Thank you to everyone who came along to this morning’s lecture. You can find the slides for the lecture by clicking on the thumbnail image of the title slide to the right, or in the links below. In the rest of this post I’ve listed the homework for Friday’s lecture and some answers to questions students asked during and after the lecture.
Continue reading Lecture 1: Introduction
Welcome to Informatics 1: Data & Analysis (Inf1-DA). If you are interested in following the course then please come to the opening lecture on Tuesday morning.
Links: Lecture slides; Course website for last year
||Tuesday 17 January 2017
||Appleton Tower Lecture Theatre 4
Links: Appleton Tower (Map), Lecture Theatre 4