Learning Blog

 This week we learned about security, particularly about encryption and how keys are used in networks to protect data. It's interesting to learn about encryption techniques that are now obsolete due to improvements in computing processors. I wonder how long it would take for currently recommended encryption methods to become obsolete. Also, I found the examples in the lectures helpful. Thinking of the data exchange across a network as a conversation between two people (and possibly three if we include an eavesdropper) helps me understand the flow of data and vulnerabilities that can arise.

 This week we continued to learn about HTTP, plus DNS and email protocols. I find the the material very interesting based on the lecture videos, but I still need to finish catching up on the reading. I think I need to review some of the earlier material on calculations and measuring response and request times, since quiz questions in later chapters seem to require this. I didn't have the technical issues I had last week. Although I do wish the labs could be turned in as assignments rather than quizzes (more flexibility for asking questions and dealing with technical vm issues).

 Journal Entry for Week 1: This week we had an introduction to networking. We also started setting up our environments for the tools we'll be using in future assignments. The lecture videos were pretty straightforward and easy to follow. However, the installation instructions for our tools didn't seem to be complete (particularly for Mac's). But I was able to set that up in my own environment with the help of our class TA and professor, and I enjoyed working with new tools like Wireshark and Ubuntu virtual machines.

 I'm enjoying the course so far. In this course, I have learned the following: The different types of databases and their uses How to use MySQL using Workbench How to use join statements to retrieve data from multiple tables How to use views to reuse or control the use of select statements How to design databases to reduce redundancy and inconsistencies Some questions I still have: I would like to know about key differences in designing databases with different concerns (size, security, enterprise vs consumer, etc). I'm curious about any current trends in database implementations and how that's changing in real time. I would like to know how databases handle other types of data, like images, video, etc.

1. ) 3rd normal form is basically a set of guidelines used to normalize databases. At the third level, the rule is that in tables where multiple columns are part of the key, the other columns should depend on the information in all key columns. This is important because if non-key columns are related to one column in the key but not others, it suggests that some columns of the data aren't closely related. The data would be better organized in separate tables to simplify access and maintenance. 2.) A SQL view is a way to display information found in one or more tables, but in a customized way with SQL queries. Views also help with reusability when the data needs to be displayed in a way that's much different than the underlying table saved in memory, or requires complex queries.

 1.) One example where joining tables on something other than equality between keys is when another comparison needs to be considered as well. Our textbook has a good example. Suppose there is a table for students and another table for classes. We can join the two tables based on matching unique codes for classes in both tables AND another comparison to check if the student's grade is greater than the average grade for the class. An example of a query would be: SELECT Student.name  FROM Class  INNER JOIN Student  ON Student.grade > Class.average AND Student.class_id = Class.class_id 2.) I feel SQL is pretty easy to pick up due to its similarity to spoken English. Sometimes when subqueries are nested it's a bit harder to figure out where the information is coming from, but views can be an alternative to simplify the syntax.