Constructing a model in a relational database using ERD allows students to understand and practice modeling concepts in relational databases.

Create an entity relation diagram $($ERD$)$ model $($using correct connection symbols for relations$)$ for a relational database based on the Crow's Foot notation using the following requirements:

An INVOICE is written by a SALESREP. A sales representative can write many invoices, but an invoice is written by a single sales representative.

The INVOICE is written for a single CUSTOMER. However, each customer can have many invoices.

An INVOICE can include many detail lines $($LINE$)$; each Line describes one product and the number of products, as well as total cost bought by the customer.

The product information is stored in a PRODUCT entity.

The product$$s vendor information is found in a VENDOR entity. $($You may assume each vendor can have many products and a product can be obtained from many vendors.$)$

After meeting above statements, you can add any additional entities or relations you seem fit.

Make sure your relations meet the requirements specified $($weak vs strong entity, participation rules, required or optional attributes, naming convention, etc.$)$

Add appropriate indexes to entities.

Submit your ERD diagram. Make sure you add at least two attributes for each entity and identify required or optional attributes.