What is a Schema?

• Simply put, the schema is nothing more than all the entities of your ERD converted to the relations of the database. Each relation contains all the attributes (columns). All the primary and foreign keys are indicated, normally by underlines or dashed underlines. Relation between tables is normally indicated in some fashion. In Oracle, the schema contains all the “Database Objects” that a user has access to. So, the Oracle Schema is user specific.

Assignment

Using the INVOICE table structure shown below, do the following:

1. Write the relational schema, draw its dependency diagram, and identify all dependencies, including all partial and transitive dependencies. You can assume that the table does not contain repeating groups and that any invoice number may reference more than one product. (Hint: This table uses a composite primary key.)
2. Remove all partial dependencies, draw the new dependency diagrams, and identify the normal forms for each table structure you created.
3. Remove all transitive dependencies and draw the new dependency diagrams. Also, identify the normal forms for each table structure you created.

What is Normalization?

• Put simply, normalization is an attempt to make sure you do not destroy true data or create false data in your database.
• Read the following information: Description of the database normalization basics (Microsoft, 2021).