Create ERD You are to design a database for the department of the Smallville town environment

control agency. This agency controls and maintains the water meters installed in the

Smallville buildings. All the water meters are linked to the consumers.

For all the Smallville consumers, the agency records a unique consumer ID$,$ first and

last names, billing address $($Street$,$ Zip$).$

Every meter must be linked to the consumer responsible for this meter. A consumer can

be responsible for several meters. But every meter is assigned to only one consumer.

For every meter, the Smallville$$s environment control agency records the information

about this meter$$s unique serial number, date the meter was produced, and date

installed. Besides, for each meter, the agency keeps the information about its model. For

each water meter model, we know its ID$,$ producer name, and the price of a meter of

this model. The environment control agency stores the information about all the water

meter models available on the market, even if no meter of this model is currently

installed in Smallville.

The meters are regularly checked by controllers from the ABC company and

maintenance workers who are hired by the Smallville town environment control

agency.

For every controller the agency stores: unique controller ID$,$ first and last names, contact

phone number unique controller certificate number, the certificate expiration date.

For every maintenance worker the agency stores: unique maintenance worker ID$,$ first

and last names, contact phone number.

To keep their qualifications up to date the maintenance workers must attend the

agency workshops. After attending a workshop a maintenance worker is issued a

certificate stating that the maintenance worker's qualifications are up$-$to$-$date. Each

certificate has a unique certificate ID$,$ and the date the certificate was issued. For every

workshop, the environment control agency keeps the information about the workshop

ID$,$ date, and time. The first thing that anyone who is hired as a maintenance worker

does is attending a workshop to obtain the agency maintenance worker certificate. Over

the tenure in the agency, a maintenance worker attends workshops every six months.

Every meter is checked every month by controllers and maintenance workers. Both a

controller and a maintenance worker should be present during a meter checkup

procedure: while a controller records the meter reading, a maintenance worker

examines the meter for any technical problems. For every check$-$up$,$ the agency stores a

unique check$-$up record number, the reading $($certified by the controller$)$ and the

comments regarding the meter state $($submitted by the maintenance worker$).$ If no

comments are recorded for the reading it means that the meter functions normally, and

no further maintenance work is required.