What are the elements of good database design?, computer science assignment help

What are the elements of good database design?, computer science assignment help

What are the elements of good database design?

To begin with, keys make the tables relatable to each other and are often used for other purposes than just primary or foreign keys. A good example of this is an employee number. An employee number is generally a primary key in a table used to uniquely identify employees. Outside the table, it is used in payroll and administrative functions throughout a company that have nothing to do with a table. If anyone is having problems grasping that idea, think of your student ID here at APU or AMU. I would bet it was assigned through a database form that added an entry to a table which returned an auto-numbered field. This key is typically one column, but it can be more. Often another table has a foreign key that relates back to this primary key in a parent child relationship. Think of this class in the university database, the list of students in this class might be table & might have a foreign key of student ID numbers that reference the primary key in list of students.

Relationships are the how the database associates the tables together using the keys. By using the relationships, the database makes all the data available throughout the entire relational database while not duplicating any data. There are three types of relationships and the first one is One to One. One example would be a table of building exits that relates back to a table of fire exits. The second relationship is one to many, with an example of this class. This class could be a table with a relationship to all the student tables so we can have a roster and all our grades can be tracked. The many to many is the last kind of relationship and several examples have popped into my head while I was typing this post.

Integrity in a database keeps things in the correct form and the relationships in the correct form. There are two kinds of integrity. The first is entity integrity and it ensures that a primary key cannot be null (empty). This keeps a database from trying to point back to a blank value. The second kind is referential integrity and it keeps the relationships between the tables operating correctly. It keeps us from deleting data that is being used somewhere else and does not allow us to create a faulty relationship that does not correctly reference a primary key.

Now we can discuss the elements of good database design being the components of one. That would be tables, forms, queries, reports. The tables are made up of columns or fields and rows or records. The other components all reference, update, add, or delete the tables. Temporary variables can be setup to hold a value from a query, but the data is only in volatile memory. However, I think the above paragraphs are more what the professor is looking for this week.

For my question this week, what is an example of a many to many relationship? If you are having problems thinking of one, think about the database this university must have to track students, instructors, classes, academic plans, etc.

References

Litwin, P. (2003). Fundamentals of Relational Database Design. Retrieved from http://r937.com/Relational.HTML

Stephens, R. & Plew, R. (2003). The Elements of a Database. Retrieved from http://www.developer.com/db/article.php/10920_7190…

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