The following describes the purchases and cash disbursement procedures for a company whose current information system includes manual procedures supported by independent (nonnetworked) PCs in each department. Communications between departments is entirely through hard-copy documents. 

Purchasing Process

The purchasing agent receives an inventory status report from the Inventory Control department, which identifies the items that need to be reordered. The agent selects the suppliers, enters this information into the computer terminal to create a digital purchase order, and then prints three hard copies of the purchase order. He sends one copy to the supplier; one copy to the AP department, where it is filed temporarily, and files the third copy in the purchasing department.

When the goods are received, the receiving department inspects and verifies them using the packing slip, which is attached to the goods. The receiving clerk manually prepares two hard copies of a receiving report. One copy accompanies the goods to the warehouse for storage. The receiving clerk sends the second copy to the purchasing agent who closes the open purchase order. The purchase agent then forwards the receiving report to the inventory control clerk.

The inventory control clerk receives the receiving report and updates the inventory subsidiary. At the close of business, the clerk prepares an inventory summary, which he sends to the GL clerk.

Accounts Payable and Cash Disbursements Procedures

The AP clerk receives the supplier’s invoice and reconciles it with the purchase order in the temporary file. From her computer terminal, the clerk records the purchase in the purchases journal and records the liability by adding a record to the AP subsidiary ledger. The purchases order and invoice are then filed in the department.

Each day, the AP clerk visually searches the AP subsidiary ledger from her terminal for invoices that are due to be paid. The clerk prepares the check and records it in the digital check register. The negotiable portion of the check is mailed to the vendor, and a check copy is filed. The clerk then closes the liability in the AP subsidiary ledger and prepares a journal voucher, which she sends to the GL clerk.

Required

Assume that the system described is to be automated using a relational database system. Prepare:

a) An entity level data model containing only entities and show the cardinalities between them (no attributes are required), which will support the tasks and user views depicted in the description.

b) A 3NF model depicting attribute, primary keys, foreign keys, and cardinality. You may need to make assumptions about how certain automated activities will be performed.