其中: R-K-degree Relation Name A;-The attribute of K-degree R B,一为R中第i属性名 (或列名) bconstant 0;-arithmetic compare operator 含义: Π A1,,AN(谷 B101b1...BM OM bM (R)) 121121 其中: R—K-degree Relation Name Ai—The attribute of K-degree R Bj—为R中第i属性名(或列名) bJ—constant j —arithmetic compare operator 含义: A1,…,AN( B11b1 ... BM M bM(R))