My CS Online Journey

 After taking this class, I have understood three important lessons. First, I learned the importance of a database and it's role to ensuring reliability and security in a software application. Second, I understood the importance of making software applications data keep their integrity because it can impact how reliable and accurately a program operates. Lastly, I have gained how to properly make a database in the best way by using MySQL as well as Mongodb. There are several other facts when making a database which includes designing and ER diagram, properly executing the right query, and as well as knowing how databases ensure ACID.

       There are various similarities and differences between MongoDB and MySQL. Some of their similarities are having a query language, indexing, drivers for different languages as well as making data persistence. MongoDB and MySQL also both store data and support backups. Some of their differences are how the data is modeled, their schema, and their joins. Also, both do have their query language, but they are different. MongoDB has the JSON-based query syntax and MySQL has the standard SQL query language. I would choose to use MySQL when I need complex queries that will need several joins. MongoDB has no native joins but MySQL does. I would use MongoDB when I want to have more flexibility with the data structure and avoid complexity of a rigid schemas. 

 I have learned several things during this week. I managed to practice more SQL queries in my homework 4. I also managed to review two other peers for lab 18 that we did the week before. During this week I also worked with my team to accomplish our Web App SQL. I worked with Flavio and Monica on this project. We started accessing the schema we needed by going over each other's work from lab 18. We combined several of our ideas to complete our lab 19 diagram and SQL schema. We then continued to work on the code needed for our application to be able to retrieve the information from the database we created. 

  If indexes are supposed to speed up performance of query , what does the author mean by a slow index? https://use-the-index-luke.com/sql/anatomy/slow-indexes      Indexes are known for speeding up the performance of a query but it is not the case for certain situations. The author means that the slow index is being caused by a specific reason. One reason is following the leaf node chain makes an index slow because of multiple leaf nodes that are potential m atches for the query. Another reason is accessing the table by index ROWID which can cause indexes to be slow due to the amount of data being read which can be large. Indexes can help the performance of a database but in some cases, they can't due to a badly constructed query.