What is the cardinality of the Professor relation?
Consider the join Professor Id=ProfId Teaching used in the running example of Section 11.3. Let us change the statistics slightly and assume that the number of distinct values for Teaching.ProfId is 10,000 (which translates into lower weight for
this attribute).
We cannot tell exactly, because some professors might not be teaching, but since ProfId in Teaching must be a foreign key into Professor, the latter must have at least 10,000 tuples. We can assume that this is the correct size of this relation,
because it is unlikely that many professors did not teach ever (which is the only way how there might not be a corresponding tuple in Teaching).
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Deserialize returns a reference of type:
a) object which must be cast to the appropriate type to manipulate the object b) the type that the object was originally c) Deserialized which must be cast to the appropriate type to manipulate the object d) None of the above
List the steps you should perform before entering data into a worksheet.
What will be an ideal response?
Using all capital letters leaves no room for emphasis or inflection.
Answer the following statement true (T) or false (F)
One purpose of adware is to determine users' purchasing habits.
a. true b. false