A method for profiling data for assessing referential integrity between collections of records stored in a data storage system, the method including: accessing multiple collections of records stored in the data storage system over an interface coupled to the data storage system to store quantitative information for each of the multiple collections of records, the quantitative information for each particular collection including, for at least one selected field of the records in the particular collection, a corresponding list of value count entries, wherein each value count entry includes a value and a count, wherein the value appears in at least the selected field, and wherein the count is a count of the number of records in which the value appears in at least the selected field and processing the quantitative information of two or more of the collections to generate profiling summary information, wherein processing the quantitative information includes: merging the value count entries of corresponding lists for at least one field from each of at least a first collection and a second collection of the two or more collections to generate a combined list of value count entries and aggregating value count entries of the combined list of value count entries to generate a list of distinct field value entries, wherein at least some of the distinct field value entries identify a distinct value from at least one of the value count entries; wherein each value count entry in a list of value count entries corresponding to a particular collection further includes location information, wherein the location information identifies respective locations of records within the particular collection of records in which the value appears in at least the selected field. accessing multiple collections of records stored in the data storage system over an interface coupled to the data storage system to store quantitative information for each of the multiple collections of records, the quantitative information for each particular collection including, for at least one selected field of the records in the particular collection, a corresponding list of value count entries, wherein each value count entry includes a value and a count, wherein the value appears in at least the selected field, and wherein the count is a count of the number of records in which the value appears in at least the selected field and processing the quantitative information of two or more of the collections to generate profiling summary information, wherein processing the quantitative information includes: merging the value count entries of corresponding lists for at least one field from each of at least a first collection and a second collection of the two or more collections to generate a combined list of value count entries and aggregating value count entries of the combined list of value count entries to generate a list of distinct field value entries, wherein at least some of the distinct field value entries identify a distinct value from at least one of the value count entries; merging the value count entries of corresponding lists for at least one field from each of at least a first collection and a second collection of the two or more collections to generate a combined list of value count entries and aggregating value count entries of the combined list of value count entries to generate a list of distinct field value entries, wherein at least some of the distinct field value entries identify a distinct value from at least one of the value count entries; wherein each value count entry in a list of value count entries corresponding to a particular collection further includes location information, wherein the location information identifies respective locations of records within the particular collection of records in which the value appears in at least the selected field.