Computer Science

Running head : COMPUTER SCIENCE Part 1 manikin SEQ Figure \ Arabic 1 : ERD(bFigure SEQ Figure \ ARABIC 2 : kinship schemaThe above figure is described as followsIn the customer bow , cust_no is the immemorial signalise and request_num is the unlike nominateIn the proceeds req send back , request_num is the particular key , F play and cust_no and EPnumber argon the international keysIn the facility put off , Fnumber is the master(a) key and resource is the foreign keyIn the employee carry over , number is the elemental keyIn the compositors case plan lines hedge , resource is the primary key , number and EPnumberIn the location table , number is the primary key and resource is the foreign keyIn the event plan table , EPnumber is the primary key and request_num resource and number atomic number 18 the foreign keys(c . Yes the tables ar in BCNF . In on the whole the tables above the relations be built in such a fashion that super key of the relations business officeally determines all the attri simplyes in the self-confidence relationsThere is no instance where there is a key which would functionally determine a non-prime attributePart Two2 (aSELECT s .identifier , s .name , s .email , s .major , f .nameFROM Student s , Faculty fWHERE s .facid f .facid(bSELECT c .compid , c .name ,.NumOpeningsFROM alliance c , positionp WHERE c .compid.compid AND.NumOpenings vitamin C(cSELECT s .identifier , s .nameFROM Student s , Interviewer I , high nine c , Interview int InterviewConduct icWHERE s .stdid int .stdid ANDint .interviewid ic .interviewid ANDic .interviewerid i .interviewerid ANDi .compid c .compid ANDc .compname exchangeable `NTU Corporation(dSELECT s .identifier , s .nameFROM Student s , Interviewer I , Company c , Interview int InterviewConduct ic . Positionp WHERE s .stdid int .std id ANDint .interviewid ic .interviewid ANDic! .interviewerid i .interviewerid ANDi .compid c .compid ANDp .compid c .compid ANDc .compname ilk `NTU Corporation ANDp .desc LIKE ` programme job4Outer Join operation is useful in cases where the man of a weak entity type exists in the database schema . given over the undermentioned relation the outer(prenominal) plug into relations come to its in spacious swingEmployeeEmp_id name Dept_id Phone1 Partha 1 99999992 Harry 1 90898983 blonde 2 89645654 Monica 1 78787895 Tom 3 8989898 DepartmentDept_id name1 Finance2 Admin3 HR4 ITIf we happen to join the dickens tables to find how many employees work for the departments , the IT department would not be shown as there is no mention to that in the employee table .

Say IT department has been introduced newly in the company , but without the outer join the IT dept would not appear at all giving an impression that it does not existThe pursuance is the look to desexualise the full outer join in vaticinator and Microsoft memory access DatabaseSELECT d .name , count (e .emp_idFROM department d full outer join employee e ON d .dept_id e .dept_idGROUP BY e .emp_id(bThe order number mastery initializes the customer id to grounds increments the economic value by 100 . The trigger created gets fired at the onset of inserting a course of action on the customer table . The SQL query transforms the customer_id field with the sequence created . The dual table holds the value of the sequence created , it contains the incremented valueThe oracle functions and triggers do almost the same function however the point of deflexion is that in triggers there is no return value w hereas functions cede a return value(cThe motion lo! g would entail the following in the event of arranging failureIf there is a brass failure at 8 :43 the following would accept placeThe transaction log would block the immediate last fleckpoint to check the statusChecking would imply which are the proceeding the system requires to commit and which ones to tump overbackOnce it finds that legal proceeding 5 ,6 and 7 are labeled to be furl backed it automatically does itThe early(a) transactions labeled other than the mentioned ones are not interpreted care at allThese form both(prenominal) of the most necessary transactions which needs to be roll backed in an event of failureReferences / BibliographyNavathe Elmasri (2004 . Fundamentals of Database systems , Singapore Pearson didactics PAGE 9 ...If you want to get a full essay, order it on our website: BestEssayCheap.com

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