Embodiments of the present invention relate to a declarative framework for efficient incremental information integration. In one embodiment, a method of and computer program product for information integration is provided. An integration rule is received. A first data set is accessed. A first representation of the first data is generated set based on the plurality of integration rules. The first representation is flat and includes a plurality of records. At least one index is generated. The index encodes at least one hierarchical relationship among the plurality of records. A second representation is generated of the first representation based on the at least one index. The second representation comprising nested data.