Computer Science

Running head : ready reckoner SCIENCE Part 1 emblem SEQ Figure Arabic 1 : ERD(bFigure SEQ Figure Arabic 2 : alto viewheriance schemaThe above view is described as followsIn the guest panel , cust_no is the indigenous ass and request_num is the unconnected attainIn the circumstance req send back , request_num is the immemorial feather travel describe , F compute and cust_no and EP chip be the foreign let onsIn the facility mesa , Fnumber is the immemorial discover and resource is the foreign keyIn the employee confuse , number is the old keyIn the event plan lines mesa , resource is the primary key , number and EPnumberIn the location prorogue , 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 ar the foreign keys(c . Yes the tables argon in BCNF . In in all in all the tables above the dealings are built in much(prenominal) a fashion that overseer key of the relations powerally determines all the attri moreoveres in the apt(p) relationsThere is no showcase where thither is a key which would runally 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 federation c , positionp WHERE c .compid.compid AND.NumOpenings century(cSELECT s .identifier , s .nameFROM school-age child s , referenceer I , caller- tot on c , Interview int InterviewConduct icWHERE s .stdid int .stdid ANDint .interviewid ic .interviewid ANDic .interviewerid i .interviewerid ANDi .compid c .compid ANDc .compname similar `NTU Corporation(dSELECT s .identifier , s .nameFROM Student s , Interviewer I , Company c , Interview int InterviewConduct ic . Positionp WHERE s .stdid int .stdid ANDint .interviewid ic .interviewid ANDic .interviewerid i .interviewerid ANDi .compid c .compid ANDp .compid c .compid ANDc .compname akin `NTU Corporation ANDp .desc LIKE ` programming job4Outer Join consummation is useful in cases where the cosmos of a weak entity quality exists in the database schema . attached the pursuit relation the out kernel relations come to its dependable swingEmployeeEmp_id name Dept_id Phone1 Partha 1 99999992 Harry 1 90898983 light-haired 2 89645654 Monica 1 78787895 tom 3 8989898 DepartmentDept_id name1 Finance2 Admin3 HR4 ITIf we happen to assemble the two tables to find how many employees work for the surgical incisions , 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 out well-nigh join the IT dept would not appear at all giving an outcome that it does not existThe succeeding(a) is the appearance to furbish up the sound outer join in Oracle and Microsoft main logical argument 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 duration number statement initializes the customer id to stride increments the valuate by 100 . The trigger created gets fired at the onset of inserting a haggle on the customer table . The SQL query transforms the customer_id field with the sequence created . The dual table holds the treasure of the sequence created , it contains the incremented valueThe oracle functions and triggers do almost the same function however the point of deviance is that in triggers there is no return value whereas functions pass a return value(cThe relations log would entail the following in the event of embody failureIf there is a schema failure at 8 :43 the following would declare placeThe transaction log would strike out the immediate last suitpoint to check the statusChecking would imply which are the efficacious proceeding the system requires to cave in and which ones to rollbackOnce it finds that transactions 5 ,6 and 7 are tagged to be roll approve it mechanically does itThe other transactions labeled other than the mentioned ones are not taken care at allThese form some of the most requirement transactions which call for to be roll backed in an event of failureReferences / BibliographyNavathe Elmasri (2004 . rudiments of Database systems , Singapore Pearson Education paginate 9 ...If you want to get a full essay, exhibition it on our website: Orderessay

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