CQ Air conditioning services (CQAC) perform installation and repair activities of air conditioning units in their customers premises. When a new customer requests for an installation, CQAC collects their personal details such as name, address, contact phone, email address, etc., Most of their installations are carried out in the home premises of their customers, however, some customers request them to install the air conditioning units at other premises such as their investment units/houses or offices etc., Hence, they also collect the contact person and address details of the premises where the installation has to be carried out.

Subsequently, one of CQAC employees inspects the premises and provide installation-options to the customer. The current installation-options that they provide are ducted, wall mounted and window mounted air conditioning. Once these options are finalized by the customer, a purchase order/agreement is generated by them and a copy is given to the customer. Currently 40% of the total cost is collected as advance payment from the customers.

After installing the air conditioning units by their employees, CQAC conducts an inspection visit, settles the issues if any and collects the remaining cost of the installation.

Whenever CQAC receives a repair request from their customers, the details that are related to the problem are obtained and a possible date for a repair visit is informed to them. After the completion of the repair work by their employees, an invoice is issued to the customer.

Note:

The attributes of the possible entities have not been mentioned clearly. For an example, the wall mounted air conditioning unit has properties such as HP, make and model, etc., You are required to conduct further research and identify the necessary attributes and provide their details (in a data dictionary) for all the entities that you have used in your ER diagram. Please make sure that each entity has at least two relevant attributes.

1. Data dictionary

Provide the details of attributes for all the entities. You can use a suitable tabular format to provide these details. The details must include the following properties of attributes wherever appropriate:

name

• size/length
• minimum and maximum value and/or permitted value
• required/not required for a new instance
• brief notes that are relevant