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Question

I know we can merge  two tables in case of one one relationship in ER diagram with total participation on both sides . Is it also applicable even if one of the entity is weak?? I mean in case of weak and strong entity relationship(ie identifying relationship) if both strong and weak entity have total  participation and have one to one relationship???

Comments

Pic??

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:) questions frame lost in DLL :)

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Yes might be :)

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where is my question gone lol

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I know we can merge  two tables in case of one one relationship in ER diagram with total participation on both sides . Is it also applicable even if one of the entity is weak?? I mean in case of weak and strong entity relationship(ie identifying relationship) if both strong and weak entity have total  participation and have one to one relationship???

this is my question

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We can merge 2 tables if even one side contains total participation and cardinality of entities participating in a relation is 1:1.

Moreover the notion of weak and strong entity should be clear to  you.Cardinality between strong and weak entities is 1: M and participation of weak entity must be total.So in any case cardinality between strong and weak entity is not going to be 1:1.

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In case of weak relation ship,it has to be merged with the dependent entity and we will keep string entity in separate table.THere will be strict 1:M relation and NO,you cant merge these in one table.Because if you merge then you will loose partial participation of Strong entity set which is against guidelines of RDBMS

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@ Habib sir, @ Rahul

Cardinality between strong and weak entities is 1: M. Is it always true?? but why??.
suppose we have a relation in which an employee has only one dependent, then how will it be one to many?? will it not depend on relationship definiton??

plz explain

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^ yes it is always true...there is a video regarding this on youtube..i dont remember exactly the name..search fr it....the person there has took a beautiful example of audio tapes to explain why it is so..and what will happen if its 1:1 or anything else...

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or else u can refer to pritam sirs video course on dbms(techtud)..he has also explained this in one of his videos

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okay sir. i will refer to it. thanx a lot. :)

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What if there is total participation on both sides?