Essay --

NAME SRINIVAS GADDIID 700604772HOME WORK-IIISUBJECT DATA BASE speculation AND APPLICATIONS3.11)a) occupy distinct touch on from student infixed join takes natural join hang where dept_name=comp.sci.b) ( hold name, id from student natural join takes) minus (select id, name from student natural join takes where year c) select dept_name, max(salary) from instructor convention by dept_name. d) select min(max_salary) from (select dept_name, max(salary) max_salary from instructor group by dept_name).3.12a) insert into by nature ( title, automobiletroad_id, credits ,dept_name) values (weekly seminar,CS-001,0,comp.sci).b) insert into section (sec_id,couse_id,year,semester) values(1,CS-001,2009 ,autumn).c) insert into takes(course_id,id,sec_id, year ,semester ) select cs-001,id,1,2009,autumn from student where dept_name=comp.sci.d) delete from takes where (sec_id = 1) and (course_id = CS-001) and (year = 2009) and (semester = Fall) and ( id in (select id from student where name = Chavez )) e) delete from course where course_id =cs-001.this will executed successfully because section has abroad key which has on delete cascade constraints so when we try to delete all course it will not affect any accede .f) delete from takes where course_id in (select course_id from course where lower(title) like %database%) 3.13) creation of person table-create table person (driver_id varchar(25), name varchar(25), address varchar(25), primary key (driver_id)) creation of car table-create table car (license varchar(25), model varchar(25), year int, primary key (license)) creation of incident table-create table accident (rep... ...t title) from course)) 3.23)The similar attributes of takes table and section table form a foreign key of takes, referencing section. due to this , each takes column should match at or so one section column ,and there should not be any extra columns in any group. These attribute s cannot take on the null value, since they ar part of the primary key of takes. Thus, joining section in the from article should not reflect any loss of columns in any group. As a result, there would be no change in the result.3.24) accustom sub queries in place of where clause, with one of the sub queries having a chip level sub query in the from clause as below. select distinct dept_name as D from instructor as A where (select sum(salary) from instructor where dept_name = D) = (select avg (B) from (select sum(salary) as A from instructor group by dept_name))