I’m working on a computer science discussion question and need an explanation to help me study.
Think of a purpose for creating a database and describe the database. Explain why you would want to use a database for this purpose.
A great purpose for creating a database in this day and age would be Covid19 vaccination registering and tracking. This database could let new people register, and will be useful for their vaccination day to have their information ready for the nurse performing the vaccination. this system could also let the health system and customer know if the customer has had their first and second shots or not, and plan accordingly.
What example could you offer that would demonstrate using a subquery?
In SQl you can call a subquery from SELECT, FROM, or WHERE statements.
In this example I will do a SELECT call
WHERE vaccine_number = ‘1’ ;
What example could you offer that would demonstrate using a join?
SELECT vaccine.vaccinetype, Customers.CustomerID, Location.VaccineLocation
INNER JOIN Customers ON Location.CustomerID=Customers.CustomerID ;
In your view, would you prefer using subqueries, or joins, and why?
Subqueries return a single value or set of rows, and joins return a whole row. I would use Subqueries for the return, as there is greater control over the coding.
What are some performance considerations when determining whether to use subqueries or joins?
Joins are easier and faster for the server to read and write. The main advantage of subqueries is better quality of life for the person reading and writing the code.
w3schools.com, 2021 https://www.w3schools.com/sql/
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