IPT - A Virtual Approach IPT A Virtual Approach by Peter Whitehouse
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Database Design eXercises #3

Uniqueness Constraints



X1: every entity plays at least one role

X2: every role is played by exactly one entity

X3: every role is played by exactly one entity

X4: incorrectly formed nest

Patient(patientid) has name PersonName
Patient(patientid) was admitted by Doctor(drid)
Doctor(drid) has name PersonName
[Patient(patientid) was observed at DateTime(datetimestamp)]= observation
observation had recorded Temperature(degreesc)
observation had observed BloodPressure(bptext)
observation had additional Note(notetext)
Doctors and Nurses

Applicant(applicantid) is called PersonName
Applicant(applicantid) has gender(gcode)
Applicant(applicantid) was born in Year(adcode)
Applicant(applicantid) can be reached by Phone(phnum)
Applicant(applicantid) cites Referee(refereename) who is contactible by Phone(phnum)
[Applicant(applicantid) began working in Year(adcode) for Company(coname)] = job
job entailed Position(positionname)
job finished in Year(adcode)

Program(gcode) is called ProgramName
Program(gcode) is shown on Channel(channelcode)
Channel(channelcode) is called ChannelName
Program(gcode) starts on Time(ampmcode)
Program(gcode) screens on Date(adcode)
Program(gcode) stars Actor(actorname)
Program(gcode) described by Synopsis(plotdescription)
Program(gcode) is rated as Rating(starcount)
Program(gcode) is classified as Classification(classcode)
Program(gcode) has consumeradvice Advice(advicecode)
Advice(advicecode) stands for AdviceName
Classification(classcode) means ClassificationName

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