Create a table or spreadsheet containing data about two different themes (other

Question

Create a table or spreadsheet containing data about two different themes (other than pets and owners). Each theme should have at least three columns, so the table will have at least six columns. Enter at least three rows of data into the table. The data should cause the following modification problems:

Problem 1: Enter data that causes an insert problem. Explain what the data is and how it causes the problem.

Problem 2: Enter data that causes an update problem. Explain what the data is and how it causes the problem.

Problem 3: Enter data that causes a delete problem. Explain what the data is, and how it causes the problem.

(You may also enter other rows of data that do not cause any problems.)

Explanation / Answer

Consider the following table describing students and courses they take.

Insert problem

Assume we designed the database such that null values are not allowed for StudentID as say, this is the policy of the university that every student must have studentID before being entered into the database. Now, I want to insert another course into the table which is related to "Mathematics" but I have no students enrolled in it.
Trying to insert this row will produce an insert error as we have not provided StudentID which is required.

Update problem

Update problem occurs when I partially update redundant information. For example, John's name was incomplete and we want to complete it now and correct it to "John Doe". Unless we make changes in both 1st and 3rd rows there will be inconsistency. Imagine this scenario when same value is redundant in multiple rows of this table and other tables that reference this. Then have to update all of those rows.
Example: Updated 3rd row but there remains an inconsistency in the first row.

Delete problem:

Say the 'Old Tower' building is no longer operational, hence, I delete the first row as no classes will be held there. Now, John is not enrolled in the CS101 course as we deleted that row. Moreover, CS101 course also ceased to exist.

Students StudentID (no null values allowed) Name Age CourseID CourseName Department Building 1 John 21 CS101 Intro to Computer Science CS Old tower 2 Jane 20 AE101 Aerodynamics 101 AE New Tower 1 John 21 CS805 Compiler Design CS Main building

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