Databases

Example

Let us suppose the following:

Need to organise data about university courses.
For each module:
- We have information about who are the lecturer(s)
  - Where their office is located
- Which semester the module is in
- which department is offering that module.

You could put this in a spreadsheet but you run into issues regarding:

Redundancy
- Integrity
- Consistency
Updates
Deletion of data related to values you want to remove.

When you delete an entry such as a person and you cause other related items to be deleted you are causing a deletion anomaly.
Adding information when details aren’t in place.
- Such as adding a teacher before their course is created.
  
  This is an example of an insertion anomaly.

Problems like the final two are related to how large tables present too much information at the same time.

You can fix these problems by identifying relations and creating linked tables from these relations.

Relational databases increase efficiency dramatically.