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Section schema: section (course_id, sec_id, semester, year, building, room_number, time_slot_id)  Which relational algebra expression lists courses taught in Fall 2017 but not in Spring 2018?

A relation Instructor(ID, name, dept_name, salary) is stored in a university database. Which relational algebra expression retrieves the names of instructors in the ‘Computer Science’ department who earn more than $80,000?

A company notices that its database queries are running slowly even though no schema changes were made. Upon investigation, it turns out that the data files are intact, but the indices became corrupted, and the system takes longer to locate records. Which database system component is most responsible for handling and optimizing these operations?

Suppose you have two relations:Instructor(ID, name, dept_name, salary)Department(dept_name, building, budget) Which relational algebra operation retrieves each instructor’s name along with the building of their department?

Section schema: section (course_id, sec_id, semester, year, building, room_number, time_slot_id)  To list all courses that were taught in Fall 2017 or Spring 2018 (or both), which of the following relational algebra expressions is correct?

Consider the following SQL command: delete from instructor where salary < (select avg(salary) from instructor); What is the key reason SQL executes this correctly without repeatedly recalculating the average?

Given the following relation definition: create table instructor ( ID char(5), name varchar(20) not null, dept_name varchar(20), salary numeric(8,2), primary key (ID), foreign key (dept_name) references department ); Which of the following statements is true?

The process of selecting jurors is called:

Congresswoman Smith, a four-term incumbent, is seeking reelection. During her campaign, she frequently cites a major federal bridge project in her district for which she successfully secured funding, and she sends regular mail updates to constituents about Social Security benefits, free of charge. These actions are examples of using:

During the confrontation between tennis players Jelena Ostapenko and Taylor Townsend during the U.S. Open tournament, what stereotypes were revealed?