Choosing Between Table and View: Factors to Consider

When designing a database, it is important to decide whether to use a table or a view for storing and querying data. Here are some guidelines to help you make the decision:

A table is best used when:

1. You need to store data permanently.

2. The data is updated frequently.

3. The data is used in multiple queries.

4. The data is large.

On the other hand, a view is best used when:

1. You want to simplify complex queries.

2. You want to restrict access to data.

3. You want to combine data from multiple tables.

4. You want to summarize data.

Let's take an example to illustrate the difference between a table and a view. Suppose you are designing a database for a school that needs to keep track of students, courses, and grades.

A table for students might look like this:

If you need to query this table frequently, for example to get a list of all students in grade 9, then a table is the best option.

However, if you need to combine data from multiple tables, such as a table for courses and a table for grades, then a view might be more appropriate. Here is an example of a view that combines data from the students, courses, and grades tables:

CREATE VIEW student_grades AS
SELECT students.name, courses.title, grades.grade
FROM students
JOIN grades ON students.id = grades.student_id
JOIN courses ON grades.course_id = courses.id;

This view can then be queried to get information on students, courses, and grades all in one place. For example, you could run a query like this to get a list of all students and their grades:

SELECT name, grade FROM student_grades;

In summary, the choice between a table and a view depends on the specific needs of your database. If you need to store data permanently, use a table. If you need to simplify complex queries, restrict access to data, or combine data from multiple tables, use a view.