A method of identifying relationships between data collections is disclosed. Each data collection comprises a plurality of data records made up of data fields. The method comprises performing a relationship search process based on a first seed value and a second seed value. A first set of records from the data collections is identified based on the first seed value. A second set of records from the data collections is identified based on the second seed value. The process then searches for a common value across the first and second record sets, wherein the common value is a value which appears in a first field in a first record of the first record set and in a second field in a second record of the second record set, wherein the first record is from a first data collection and the second record is from a second data collection. In response to identifying the common value, an indication is output identifying a candidate relationship between the first field of the first data collection and the second field of the second data collection.