Understanding Data in Data Sets

Among other things, there are two or more data sets. Each of the data sets contains data that can be interpreted as records each having data values for data fields. Each of the data sets contains at least some data that is related to data in at least one of the other data sets. The data in different data sets is organized or expressed possibly differently. Each of the data sets is susceptible to a definition of a key for the records of the data set. The data sets are characterized by repetitions of at least one of (a) records, (b) portions of keys, or (c) instances of values for data fields. Information about at least one of the repetitions is provided to a user.