00:01
Hello student here eer diagrams are given and i have to find which are incorrect and which are correct.
00:06
So diagram a is shown here.
00:10
It is incorrect because the relationship between e1 and e2 is not clearly defined.
00:16
So here look at e1 and e2 here relationship is not shown clearly.
00:21
The relationship symbol n indicates that e1 have many e2s.
00:29
So here this relationship is showing e1 having many e2s but it doesn't indicate whether e2 may have many e1s.
00:38
So it doesn't indicate that e2 have many e1s but it is showing that e1 may have many e2.
00:46
So this is the problem in this diagram.
00:48
So this is ambiguous type.
00:49
So here i will write.
00:58
Number 2 diagram b.
01:06
So here first look at the diagram c.
01:09
Diagram c is also incorrect because the relationship between e1 and e3 is not clearly defined.
01:16
The relationship symbol m indicates that e1 may have many e3 and e3 may have many e1s but it doesn't indicate whether the relationship is mandatory or optional for the either entity.
01:34
So here information is not clear in the diagram c also.
01:42
Diagram b is correct because it clearly defines all the relationship between the entities.
01:47
So look at the diagram.
01:48
In this diagram e1 and e2 are the entities.
01:52
So here everything is shown very clearly and here how many to one and one to many relationship here is existing.
02:00
So everything is shown very clearly.
02:03
So here only correct is this one.
02:09
This is incorrect and this also incorrect.
02:17
So here these are the information about this diagram...