Query processing algorithm for vertically partitioned federated database systems

摘要

Querying data stores in a federation of data stores. A first search filter is accessed. The first search filter is constructed with one or more nested logical AND, OR, or NOT operands. The first search filter is normalized to a normalized search filter that is logically equivalent to the first search filter. The normalized search filter includes 3 or 4 levels. All first level operands are logically ORed. All second level operands are logically ANDed. All third level operands are at least one of parameters or logical NOTs. Any fourth level operands are parameters. The normalized search filter is used to search a plurality of data stores in a federation of data stores for information by searching different data stores for at least two or more of the top level operands.