Lossless Decomposition

Jun 28, 2023

• if $R1 \cap R2$ forms a superkey for either R1 or R2, the decomposition of R is a lossless decomposition
• 关系模式R(U)的分解r={R1，R2}，则r是一个无损连接分解的充要条件是 R1∩R2->R1-R2（或R1∩R2->R2-R1）成立

Break large into multiple superkey.