Relational Model Concepts
The relational model used the basic concept of a relation or table. The columns or fields in the table identify the attributes such as name, age, and so. A tuple or row contains all the data of a single instance of the table such as a person named Doug. In the relational model, every tuple must have a unique identification or key based on the data. In this figure, a social security account number (SSAN) is the key that uniquely identifies each tuple in the relation. Often, keys are used to join data from two or more relations based on matching identification. The relational model also includes concepts such as foreign keys, which are primary keys in one relation that re kept in another relation to allow for the joining of data. As an example of foreign keys is storing your mother's and father's SSAN in the tuple that represent you. Your parents' SSANs are keys for the tuples that represent them and they are foreign keys in the the tuple that represents you.
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