CS430 Midterm 2 Exam Practice Questions and Answers

CS430 Midterm 2 Exam Practice Questions and Answers One key difference between a natural join and an inner join is: - Ans:-the number of columns returned We define a view in SQL by using the create view command. - Ans:-True To remove an authorization, we use the ________________command. - Ans:-revoke Views are considered updatable if which of the following conditions are satisfied: - Ans:-The from clause only had one database relation The select clause contains only attribute names of the relation and does not have an expressions, aggregates or distinct specification. Any attribute not listed in the select clause can be set to null. A transaction is a single operation that performs multiple logical functions within a database. - Ans:- False ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 2/12 ____________________ are a scheme that allows authorizations to be assigned to a set of responsibilities, and people to be assigned to those responsibilities. - Ans:-Roles Outer join query operations can be implemented by a simple extension of join algorithms. - Ans:- True Indices are created by using the "GRANT index {index-name} on {relation-name} using {field-name}" command. - Ans:-False What are the two possible SQL statements that must end a transaction? - Ans:-Commit work Rollback work What is the concept of referential integrity? - Ans:-That a foreign key entry in one table must point to a valid record in the table associated with the foreign key. Which of the following is true about SQL? - Ans:-SQL is both a Data Manipulation Language (DML) and a Data Definition Language (DDL). SQL specifies strings by enclosing them in double quotes. - Ans:-False The _________________ command is used to insert data into a relation. - Ans:-insert Match the domain type to its description. ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 3/12 char(n) varchar(n) int smallint numeric real, double-precision - Ans:-char(n) - a fixed-length character string varchar(n) - a variable length character string int - integer smallint - small integer numeric - a fixed-point number with user specified precision real, double-precision - floating-point and double-precision floating point numbers Which of the following are common subqueries - a select-from-where expression nested within another query? - Ans:-set membership test for empty relations set comparison ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 4/12 test for the absence of duplicate tuples An attribute takes a null value when the value of the attribute is computed to be zero. - Ans:-False Which of the following are aggregate functions? min avg left inner join left outer join count - Ans:-avg count ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 5/12 min When using the GROUP BY clause, you cannot have a column in the select clause that is not in the grouping-list. - Ans:-False What are the 3 mechanisms to modify a database? - Ans:-Insertion Deletion Update Do the queries below return the same result? SELECT name, employee_deptFROM employee, emp_deptWHERE = emp_; SELECT name, employee_deptFROM employee NATURAL JOIN emp_dept; - Ans:-Same What are the three basic clauses of a SELECT statement? - Ans:-FROM clause SELECT clause WHERE clause Which clauses of the SELECT statement can the AS clause appear? - Ans:-from clause