What has developed a number of related concepts and terms?
Kinship can refer both to the study of the patterns of social relationships in one or more human cultures, or it can refer to the patterns of social relationships themselves. Over its history, anthropology has developed a number of related concepts and terms, such as "descent", "descent groups", "lineages", "affines", "cognates", and even "fictive kinship". Broadly, kinship patterns may be considered to include people related both by descent (one's social relations during development), and also relatives by marriage.
Just as the navigational approach would require programs to loop in order to collect records, the relational approach would require loops to collect information about any one record. Codd's solution to the necessary looping was a set-oriented language, a suggestion that would later spawn the ubiquitous SQL. Using a branch of mathematics known as tuple calculus, he demonstrated that such a system could support all the operations of normal databases (inserting, updating etc.) as well as providing a simple system for finding and returning sets of data in a single operation.