## Discussion Forum

Que. | Let r be a relation instance with schema R = (A, B, C, D). We define r1 = ΠA, B, C (r) and r2 = ΠA.D (r). Let s = r1 * r2 where * denotes natural join. Given that the decomposition of r into r1 and r2 is lossy, which one of the following is TRUE? |

a. | s ⊂ r |

b. | r ∪ s |

c. | r ⊂ s |

d. | r * s = s |

Answer:r ⊂ s |