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tempo
Starting Member
4 Posts |
 Posted - 2014-06-27 : 05:03:13
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When I connect two table should they always have a column in common with each other? For example the 'patients' and 'doctors' tables in that ER are connected to say each doctor can have many patients and each patient can have many doctors, but they have no columns in common. Is it right? |
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ahmeds08
Aged Yak Warrior
737 Posts |
Posted - 2014-06-27 : 05:19:25
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| you can have a bridge table which brings both patientid and doctoridJaveed Ahmed |
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tempo
Starting Member
4 Posts |
Posted - 2014-06-27 : 05:23:15
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| wat?Is it right or wrong? |
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ahmeds08
Aged Yak Warrior
737 Posts |
Posted - 2014-06-27 : 05:26:54
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| yes,you need to have a common column to connect both the tables.Javeed Ahmed |
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tempo
Starting Member
4 Posts |
Posted - 2014-06-27 : 05:29:33
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| And if the given in the question is "each doctor can have many patients and each patient can have many doctors" then I have to create that extra table to show this yes? |
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ahmeds08
Aged Yak Warrior
737 Posts |
Posted - 2014-06-27 : 07:30:58
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| yes,as i mentioned in the earlier postJaveed Ahmed |
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tempo
Starting Member
4 Posts |
Posted - 2014-06-27 : 09:13:29
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| And to satisfy that condition, what should the bridge table be called, and what numbers should be on the relation line? |
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Bustaz Kool
Master Smack Fu Yak Hacker
1834 Posts |
Posted - 2014-06-27 : 17:18:00
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Call it what you like (Floyd?). The important thing is that an try indicates a relationship exists between this doctor and this patient. From your diagram, it looks like SSN_D and SSN_P would be the unique identifiers for doctor and patient. A bridge table (btw, this type of table goes by many other names) could simply be those columns but you could also add columns to hold other attributes of this Doctor-Patient entity. For instance, when was the last time this doctor saw this patient, when was the first appointment, is this the primary care physician for the patient, etc?
Too often we enjoy the comfort of opinion without the discomfort of thought. - John F. Kennedy |
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naveedraza
Starting Member
1 Post |
Posted - 2014-06-30 : 01:13:41
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| @ahmeds08Assalamualaikum ahmed bhai, can i have your mail id ?Mohammad Naveed |
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Is this ER diagram right?