This paper reports an algorithm (DTV) for deterdring the minimal reducedcovering of an acyclic database scheme over a specified subset of attributes. The output of this algorithm contains not only minimum number of a...This paper reports an algorithm (DTV) for deterdring the minimal reducedcovering of an acyclic database scheme over a specified subset of attributes. The output of this algorithm contains not only minimum number of attributes but also minimum number of partial relation schemes. The algorithm has complexity O(|N|·|E|2), where |N| is the number of attributes and |E| the number of relation schemes- It is also proved that for Berge, γ orβ acyclic database schemes, the output of algorithm DTV maintains the acyclicity correspondence.展开更多
文摘This paper reports an algorithm (DTV) for deterdring the minimal reducedcovering of an acyclic database scheme over a specified subset of attributes. The output of this algorithm contains not only minimum number of attributes but also minimum number of partial relation schemes. The algorithm has complexity O(|N|·|E|2), where |N| is the number of attributes and |E| the number of relation schemes- It is also proved that for Berge, γ orβ acyclic database schemes, the output of algorithm DTV maintains the acyclicity correspondence.
