One of the properties of a normalised table, as defined in Chapter 3, is that an attribute
must have only one value in each row. The present chapter looks more closely at the
reasons for this rule, and then discusses ways in which tables may be structured so that
the rule is obeyed.
What constitutes a single value for an attribute? Suppose partNo values are defined
as two-character codes, the first character being alphabetic (not necessarily a P, as used
in the examples) and the second character numeric. Each two-character code
represents a part that may be supplied by a supplier. In Fig. 5. 1a, row 1 contains a single ...
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