CS Online Weekly Updates

This week in week 4 we had our midterm. I prepared well and am happy with my results. I have learned a lot so far and am still gaining new information. This week was primarily quizzes and homework, and we also had a lab. This lab was more Wireshark and I am understanding it a lot more through trial and error (i.e bad grades). With each mistake I learn, so I am not upset.  

This week we had our 2nd programming assignment due, UDP Pinger. I am getting more and more familiar with python and this PA sends pings to the server, and with a theoretical percentage, responds either with how long it took, or if the request timed out and the packet was lost. It then transcribes it into a file that we submitted.  Chapter 3 was about the transport layer. We learned about Transmission Control Protocol (TCP) and UDP - User Datagram Protocol. Both have their pros and cons, and are needed for different tasks. We also learned about multiplexing and demultiplexing. 

This week was more quizzes and a few labs. The labs are unique as they use Wireshark which is new to me as well. But still getting used to it. I understand what it is doing but I am struggling trying to find where everything I need is like the IP's, but I get there slowly but surely. But it is interesting seeing how the client and the server interact. Chapter 2 we are learning about the application layer and a lot about the client-server connections. There are multiple kinds of HTTP's and different kinds of cookies. We also learned all about DNS and the kinds of DNS there are like A, NS, AAAA depending on the IPv6 or other reasons. 

This week was very new to me. Starting a new class and using a language I have had very minimal experience in. So this week I took some time to review Python and do the beginning program assignment. The mininet we use is also very new to me but I will get the hang of it. In chapter 1 we learned about the network and how a computer network is set up with its protocols, what bandwidth is, the different types of internets, and much more. Excited to see what this course offers!

 Summary of what I have learned so far 1. SQL can select items from a table and filter them by using WHERE/HAVING and then group them and order them. 2. Different SQL tables can be joined together if they share a common column. These joining can also be filtered and only choose select columns depending of which join you do. 3. If there is already a table and you have new data you can INSERT new rows to the table and specify what values they are. 4. There are also different kinds of custom tables. There is a view which is a query that is stored in the database that can be used in other queries. Then there is also a Common Table Expression where a table is made and has a single query after it.  5. SQL can also alter stables using CREATE ALTER or DROP. These can make tables, add or fix columns, and then even remove database object. It is a great way to manage database architecture.  Some questions I have are... 1. I understand what normalization does and splitting it up, but...

What is an SQL view.  How is it similar to a table? In what ways is it different (think about primary keys,  insert, update, delete operations) ? 1. SQL View is a virtual table made of columns from tables. It is similar to a table since they both have data types in columns, and they both can use queries and joins. The difference is that the View stores the query, not the real data. A view also can not be indexed or have primary keys, insert/updaet/deletes do not work all the time. The pro of a view is that is conserves minimal space compared to a table due to not storing data. 2.We have completed our study of SQL for this course.  This is not to imply that we have studied everything in the language.  There are many specialized features such as calculating rolling averages, query of spatial data (data with latitude and longitude) coordinates, and more. But take a minute to think about how SQL compares to other programming languages such as Java.  What features ar...

1) SQL has the flexibility to join tables on any column(s) using any predicate (=, >, < ).    Most of the time the join will use equality between a primary and foreign key.   Think of example where joining on something other than keys would be needed.  Write the query both as an English sentence and in SQL One example of this would be if a customer is in a city and wants to know what stores there are. If there is a customer table with id, name, and city and then a stores table with id, name, and city, we can use city as the shared attribute since it is. not a primary or foreign key. " Find all customers and the stores that are located in the same city as the customer. "  SELECT      c.customer_id,     c.name AS customer_name,     s.store_id,     s.store_name FROM      customers c JOIN      stores s ON      c.city = s.city; 2)  What is your opinion of SQL as ...

Week 1 1. The difference in database tables and spreadsheets is that databases make sure and can check data for constraints and can use SQL to manage relations between different tables. But with spreadsheets they can not validate data or scale or access multiple tables. Spreadsheets are however more user friendly and a good option for small and simple tasks.  2. After going through the labs and using a database for the first time its obvious that the database is worth the investment as it manages large sets of data with many features like being able to access multiple sources of data at once, can scale, and can index.  3. This course uses a lot of SQL so I want to learn more about it and its ins and out and be as proficient as possible. I feel like it can be super useful in the future as every app or internet program will be data driven, so being able to manage that data in an efficient way is key to a successful career.