2. The computer program product of claim 1 , wherein the conditional selection operation comprises selecting a single value from at least two duplicated rows in the partitioned tabular data and selecting a marker value for other rows of the at least two duplicated rows in the partitioned tabular data.
1. A computer program product for avoiding double counting of mapped database data, the computer program product comprising: one or more computer readable storage media and program instructions stored on the one or more computer readable storage media, the program instructions comprising instructions to: receive a report definition from a data management system, wherein the report definition comprises a request to obtain information from at least two datasets, and wherein the report definition specifies a field in the at least two datasets for deduplication; detect a fact-less fact table defining many-to-many relationships between at least two datasets; generate automatically, a query plan with layered sub-queries against the at least two datasets, wherein the query plan includes instructions to: join the at least two datasets with the fact-less fact table to provide tabular data, partition the tabular data using the fact-less fact table to provide partitioned tabular data, normalize the partitioned tabular data using a conditional selection operation to provide normalized tabular data, wherein the conditional selection operation removes duplicates in the field specified by the report definition, and group and summarize the normalized tabular data to provide summarized tabular data; and execute the query plan comprising the layered sub-queries to provide query results corresponding to the report definition.