Your dataset is not an island. Somewhere, related datasets exist, even in places where you might not expect them. For instance, if your dataset has a Country of Origin column, then it is related to a geographical database that lists the total area per country. An Author column in a book dataset relates to a list of authors with biographical data. All datasets have such connections, yet you might not know about them, and neither does the computer which contains your dataset. For instance, the record for
The Picture of Dorian Gray might list
. as its author, whereas a biographical dataset might only have an entry for
Oscar Wilde. Even though they point to the same person, the string values are different, and ...