2 votes 2 votes In ER model, which of the following is TRUE about weak entity Weak entity is not always existence dependent i.e., weak entity can exist without the entity with which it has a relationship Weak entity has a primary key that is partially or totally derived from the parent entity in a relationship Only I Only II Both I and II Neither I nor II Databases er-diagram + – Mk Utkarsh asked Jan 14, 2019 recategorized Jan 14, 2019 by Shaik Masthan Mk Utkarsh 1.1k views answer comment Share Follow See all 14 Comments See all 14 14 Comments reply Deepanshu commented Jan 14, 2019 reply Follow Share i think only 2nd correct 1 votes 1 votes Shamim Ahmed commented Jan 14, 2019 reply Follow Share 1 is wrong. In case of 2nd the weak entity should be totally dependent to the parent right? 0 votes 0 votes Deepanshu commented Jan 14, 2019 reply Follow Share Shamim Ahmed yes totally dependent but they asking primary key which is combination of both from weak and primary 0 votes 0 votes Shaik Masthan commented Jan 14, 2019 reply Follow Share @Mk Utkarsh what this Applied Course means ? 0 votes 0 votes Mk Utkarsh commented Jan 14, 2019 reply Follow Share Its a Test series https://gate.appliedcourse.com/tests 1 votes 1 votes Shaik Masthan commented Jan 14, 2019 reply Follow Share ok... but didn't you responds on comments of this question ? 0 votes 0 votes Mk Utkarsh commented Jan 14, 2019 reply Follow Share Shaik Masthan can you explain 2nd part? 0 votes 0 votes Shaik Masthan commented Jan 14, 2019 reply Follow Share as per me it is false. weak entity always have a partial key, To make it primary key we are depend upon some strong entity Primary key of Weak entity = partial Key of it's + Primary key of Strong entity ex:- let red colored are dependents of E1 and Green colored are dependents of E2 name age $\color{red}{\text{Masthan 24}}$ $\color{red}{\text{MK 24}}$ $\color{green}{\text{Masthan 25}}$ $\color{green}{\text{MK 24}}$ with in a dependents of a particular employee, we can use name as key and found them uniquely But acorss all dependents we can't use name as key, So we take help of Strong entity 1 votes 1 votes Mk Utkarsh commented Jan 14, 2019 reply Follow Share In answer key 2 is given as true :( 0 votes 0 votes Shaik Masthan commented Jan 14, 2019 reply Follow Share just think if there is one more $\color{red}{\text{Masthan 24}}$ is present, then it can't be find even after getting the key from strong entity ! isn't it ? 0 votes 0 votes Mk Utkarsh commented Jan 14, 2019 reply Follow Share Yes I agree with u 0 votes 0 votes Deepanshu commented Jan 14, 2019 reply Follow Share when i read 2nd statement thats what i think they are saying weak entity has primary key means they specify yes primary key we have already then they say it is partial derived or fully derived from table both cases are possible 0 votes 0 votes Shaik Masthan commented Jan 14, 2019 reply Follow Share i didn't get you brother @deepanshu 0 votes 0 votes DAWID15 commented Dec 28, 2021 reply Follow Share weak entities don’t have primary key they have partial keys. So I think(not sure) 2 statement is also false. 0 votes 0 votes Please log in or register to add a comment.
0 votes 0 votes Total participation is also called Existence Dependencies. Weak entity have always a total participating constraint because they cannot be identified without an owner entity. Hence, option 1 is simply wrong from the definition itself. AkashChandraGupta answered Oct 7, 2019 AkashChandraGupta comment Share Follow See 1 comment See all 1 1 comment reply moin commented Aug 16, 2022 reply Follow Share Point 1 is straight false. No doubt about it. but please clear about point 1 0 votes 0 votes Please log in or register to add a comment.