Why does the relation created as result of a Projection operation on a relation that includes the primary key not contain fewer tuples than those in the source relation?

QUESTION: Why does the relation create a result of a Projection operation on a relation that includes the primary key not contain fewer tuples than those in the source relation?   [signinlocker] SOLUTION   There are no duplicate tuples to eliminate since the value of...
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With which of the four types of constraints in Exercise 4 is a requirement that an attribute not contain a null value associated?

QUESTION: With which of the four types of constraints in Exercise 4 is a requirement that an attribute not contain a null value associated?   [signinlocker] SOLUTION   A not null constraint is associated with a CHECK clause. [/signinlocker]
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What is the difference between a column-level constraint and a row-level constraint?

QUESTION: What is the difference between a column-level constraint and a row-level constraint?   [signinlocker] SOLUTION   A column-level constraint is imposed on a single column in the table while a row-level constraint is imposed on a set of columns in the table. [/signinlocker]
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What are the minimum elements that must be included in the CREATE TABLE statement in defining the structure of a table?

QUESTION: What are the minimum elements that must be included in the CREATE TABLE statement in defining the structure of a table?   [signinlocker] SOLUTION   The CREATE TABLE statement must contain the table name, the names of the columns in the table, and the...
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What are the undesirable functional dependencies in the relation instance of the STUCLASS relation schema shown in Exercise 6?

QUESTION: What are the undesirable functional dependencies in the relation instance of the STUCLASS relation schema shown in Exercise 6?   [signinlocker] SOLUTION   Snum → Sname, Snum → Major, Cname → Time, Cname → Room, Time → Cname, Time → Room. [/signinlocker]
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What is the role of normalization in the database design process?

QUESTION: What is the role of normalization in the database design process?   [signinlocker] SOLUTION   The role of normalization in the database design process is to render undesirable functional dependencies desirable. [/signinlocker]
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