My CS Journey

Here are a few things I have learned so far in this class. I have learned how relational databased store data in tables with relationships using primary and foreign keys. I also know how to use SQL commands such as select, insert, update, where, and group by. I understand how to read ER diagrams and how to create them for a new database. I know that there are more efficient ways of looking up data in a database. For example, a full table scan is simple but takes more time and power to find data whereas an index search is faster because it looks up specific keys to jump to a row.  There are several types of table storage structures that are used in databases such as heap tables, sorted tables, hash tables, and table clusters.  A few questions I still have are: How are databases structured that take input from external users around the world. It seems like it would use a lot of processing power to for an e-commerce site that is constantly taking in orders. How do we debug when w...

 1. A SQL view is used to restructure table columns and data without changing the database design. It helps to combine data from separate tables into one. A view table does not store any data, only displays it from a query. A view can be joined with other tables or views. A view table does not support insert, update or delete. It also does not have primary keys or indexes and are read-only. 2. SQL is similar to java in that it uses conditional logic to filter data like WHERE in SQL and IF in Java. The Select statement in SQL is similar to a return statement in Java which are used to display certain data. One main difference is that in Java, you have to tell the program what to do to return the data that you want whereas in SQL you merely ask for the data you are looking for. 

 1. One example would be to match employees to managers is the employee’s salary is higher than the manager’s salary. Select e.name, m.name From employee e Join manager m ON e.salary > m.salary 2. I think SQL is somewhat easy to learn because the keywords used are common words like Select and From. It’s sometimes easy to understand what the prompt is asking you to do. The difficult parts are learning when to use Join or when to Group tables together. It can help sometimes be helpful to draw it out on paper how tables should be joined.  

 1. One difference is that databases have rules like preventing the insertion of duplicate values. Databases also helps connect data between tables more easily than in spreadsheets and would have better performance when many users are accessing the system. Databases can restrict access to certain data to only some users.  2. Investing time into a database is important because it can increase the efficiency of work by keeping data secure, restrict access of certain types of data to only some users and has ways to recover data if crashes occur.  3. I want to learn how to build apps and systems that use databases since they connect complex systems together. I think it's important to design databases that are organized to facilitate its integration into more complex apps. At the most basic level, I would like to learn how to better write SQL queries and memorize more functions and keywords.