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Database Lossless Join

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  A B C D E G
R1 X X        
R2   X X      
R3 X X   X X  
R4         X X

Applying functional dependencies E-> G, we can put X in column G of R3, but we cannot get any row with all X.

So D1 is lossy.

  A B C D E G
R1 X X X      
R2 X   X X X  
R3 X     X   X

Applying functional dependencies, AC-> B, we can put X in B. Still no row with all X.

So lossy.

Hence option D.

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