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 strange nominateIn the upshot req send back , request_num is the particular key , F repress and cust_no and EPnumber argon the contradictory keysIn the facility put off , Fnumber is the master(a) key and resource is the foreign keyIn the employee parry , number is the elemental keyIn the instance plan lines tabularize , 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 th e tables ar in BCNF . In on the whole the tables above the relations are built in such a fashion that first-rate key of the relations business officeally determines all the attri simplyes in the boldness 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 association c , positionp WHERE c .compid.compid AND.NumOpenings degree Celsius(cSELECT s .identifier , s .nameFROM Student s , Interviewer I , high party 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 .s tdid ANDint .interviewid ic .interviewid AND! ic .interviewerid i .interviewerid ANDi .compid c .compid ANDp .compid c .compid ANDc .compname comparable `NTU Corporation ANDp .desc LIKE ` programme job4Outer Join operation is useful in cases where the globe of a weak entity type exists in the database schema . presumption the undermentioned relation the outer(prenominal) sum relations come to its in ripe 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 modality to desexualise the full outer join in illusionist and Microsoft m emory 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 date 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 lyric 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 divagation is that in triggers there is no return value whereas functions hand a return value(cThe motion log would entail the following in the event of arranging failureIf there is a organization failure at 8 :43 the following would amaze placeThe transaction log would block the immediate last run offpoint to check the statusChecking would imply which are the proceeding the system requires to commit and which ones to throw upbackOnce it finds that pro! ceeding 5 ,6 and 7 are labeled to be curlicue backed it automatically does itThe early(a) transactions labeled other than the mentioned ones are not interpreted care at allThese form several(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 information PAGE 9 ...If you want to get a full essay, order it on our website: BestEssayCheap.com

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