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for three examples 11 —and I've certainly been using the double underlining convention in those pictures. So what
can we say about that convention now?
4.14 ( Repeated from the body of the chapter. ) Give Tutorial D formulations of the following queries against the
relation shown in Fig. 4.1:
Get part numbers for parts supplied by supplier S2.
Get supplier numbers for suppliers who supply part P2.
4.15 Suppose we need to update the database to show that supplier S2 supplies part P5 in a quantity of 500. Give
Tutorial D formulations of the required update against (a) the non RVA design of Fig. 1.1, (b) the RVA design of
Fig. 4.1.
4.16 Here are some definitions of 1NF from the technical literature. In view of the explanations given in the body
of the present chapter, do you have any comments on them?
First normal form (1NF) … states that the domain of an attribute must include only atomic (simple,
indivisible) values and that the value of any attribute in a tuple must be a single value from the domain of that
attribute … 1NF disallows having a set of values, a tuple of values, or a combination of both as an attribute
value for a single tuple … 1NF disallows “relations within relations” or “relations as attribute values within
tuples” … the only attribute values permitted by 1NF are single atomic (or indivisible ) values (Ramez
Elmasri and Shamkant B. Navathe, Fundamentals of Database Systems , 4th edition, Addison-Wesley, 2004)
A relation is in first normal form if every field contains only atomic values, that is, no lists or sets (Raghu
Ramakrishnan and Johannes Gehrke, Database Management Systems , 3rd edition, McGraw-Hill, 2003)
First normal form is simply the condition that every component of every tuple is an atomic value (Hector
Garcia-Molina, Jeffrey D. Ullman, and Jennifer Widom, Database Systems: The Complete Topic , Prentice
Hall, 2002)
A domain is atomic if elements of the domain are considered to be indivisible units … we say that a relation
schema R is in first normal form (1NF) if the domains of all attributes of R are atomic (Abraham
Silberschatz, Henry F. Korth, and S. Sudarshan, Database System Concepts , 4th edition, McGraw-Hill, 2002)
A relation is said to be in first normal form (abbreviated 1NF) if and only if it satisfies the condition that it
contains scalar values only (C. J. Date, An Introduction to Database Systems , 6th edition, Addison-Wesley,
11 Yes, I do mean three.
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