1. Hwrk Week 5: solutions
CS240A Fall 2014

2. Exercise 6.1

3. Write a recursive SQL query to coalesce the periods after Sal is projected out from EHist(Eno, Sal, Title, From, To)
with coal(SSN, LNAME, FNAME, Salary, Start, End, CNT) As
((select SSN, LNAME, FNAME, Salary, From, To, 0 from histemp)
union all
(select coal.SSN, coal.LNAME, Coal.FNAME, Coal.Salary, Start, To, CNT+1
from coal, histemp
where CNT<5 and histemp.SSN = coal.SSN and histemp.Salary=coal.Salary and
Start <= From and From <= End and End < To))
select distinct * from coal
Answers

4. with coal(SSN, LNAME, FNAME, Salary, Start, End, CNT) As
%Write a recursive SQL query to coalesce the periods after Sal is projected out from %EHist(Eno, Sal, Title, From, To) CREATE TABLE HistEmp( SSN CHAR(11) NOT NULL, LName CHAR(20), FName CHAR(20), Salary INTEGER, Dno INTEGER, From Date, To Date) insert into HistEmp values (' ', 'Smith', 'John', 30000, 5, '01/09/1965', '01/09/1966'), (' ', 'Smith', 'John', 40000, 5, '01/09/1966', '01/09/1967'), (' ', 'Smith', 'John', 40000, 4, '01/09/1968', '01/09/1969'), (' ', 'Smith', 'John', 40000, 6, '01/09/1969', '01/09/1970'), (' ', 'Smith', 'John', 45000, 6, '01/09/1979', '01/09/1990'), (' ', 'Wong', 'Franklin', 40000, 2, '12/08/1955', '12/08/1956'), (' ', 'Wong', 'Franklin', 40000, 3, '12/08/1956', '12/08/1957'), (' ', 'Wong', 'Franklin', 40000, 4, '12/08/1957', '12/08/1958'), (' ', 'Zelaya', 'Alicia', 25000, 2, '07/19/1998', '07/19/1999'), (' ', 'Zelaya', 'Alicia', 26000, 2, '07/19/1999', '07/19/2001');
% The coalesce query
with coal(SSN, LNAME, FNAME, Salary, Start, End, CNT) As
((select SSN, LNAME, FNAME, Salary, From, To, 0
from histemp)
union all
(select coal.SSN, coal.LNAME, Coal.FNAME, Coal.Salary,
Start, To, CNT+1
from coal, histemp
where CNT<5 and
histemp.SSN = coal.SSN and histemp.Salary=coal.Salary and
Start <= From and From <= End and End < To))
select distinct * from coal
% from the records above, produces
SSN LNAME FNAME SALARY START END CNT
Wong Franklin /08/ /08/
Wong Franklin /08/ /08/
Wong Franklin /08/ /08/
Smith John /09/ /09/
Smith John /09/ /09/
Smith John /09/ /09/
Smith John /09/ /09/
Smith John /09/ /09/
Zelaya Alicia /19/ /19/
Zelaya Alicia /19/ /19/
Wong Franklin /08/ /08/
Wong Franklin /08/ /08/
Smith John /09/ /09/
Wong Franklin /08/ /08/

5. Store the results of Colalescing
% We will now run the same query and eliminate tuples with non-maximal periods with coal(SSN, LNAME, FNAME, Salary, Start, End, CNT) As ((select SSN, LNAME, FNAME, Salary, From, To, 0 from histemp) union all (select coal.SSN, coal.LNAME, Coal.FNAME, Coal.Salary, Start, To, CNT+1 from coal, histemp where CNT<5 and histemp.SSN = coal.SSN and histemp.Salary=coal.Salary and Start <= From and From <= End and End < To)) select distinct * from coal where not exists (select * from coal as C where C.SSN=coal.SSN and C.Salary=coal.Salary and C.start <= Coal.start and C.end>=coal.end and (C.start <Coal.start or C.end>coal.end)) % We now stores these results into HistSal CREATE TABLE HistSal( SSN CHAR(11) NOT NULL, LName CHAR(20), FName CHAR(20), Salary INTEGER, From Date, To Date); % We now do the same for departments
% We now do the same for departments insert into HistDep(SSN, LNAME, FNAME, DNO, From, To) with coal(SSN, LNAME, FNAME, DNO, Start, End, CNT) As ((select SSN, LNAME, FNAME, DNO, From, To, 0 from histemp) union all (select coal.SSN, coal.LNAME, Coal.FNAME, Coal.DNO, Start, To, CNT+1 from coal, histemp where CNT<5 and histemp.SSN = coal.SSN and histemp.DNO=coal.DNO and Start <= From and From <= End and End < To)) select distinct SSN, LNAME, FNAME, DNO, Start, End from coal where not exists (select * from coal as C where C.SSN=coal.SSN and C.DNO=coal.DNO and C.start <= Coal.start and C.end>=coal.end and (C.start <Coal.start or C.end>coal.end)); % the content of histdept select * from histdep

6. Here EHist(Eno, Sal, Title, From, To) is a concrete view that stores the transaction time history for the relation EMP(Eno, Sal, Title). The concrete view must be maintained by active DB2 rules. Please write those rules.
CREATE TRIGGER HireEmployee AFTER INSERT ON EMP FOR EACH ROW INSERT INTO EHist VALUES(Eno, Sal, Title, CURRENTDATE, ) % we use to denote 'until changed’ CREATE TRIGGER FireEmployee AFTER DELETE ON EMP UPDATE EHist SET To = CURRENTDATE WHERE EHist.Eno = OLD.Eno AND EHist.To = CREATE TRIGGER ChangeEmployee1 AFTER UPDATE ON EMP CREATE TRIGGER ChangeEmployee2 VALUES(Eno, Sal, Title, CURRENTDATE, =31)

7. events(itemNo, SensorNo, SensorType, Time)
SELECT AitemNo
FROM events MATCH-RECOGNIZE
( PARTITION BY itemNO ORDER BT Time
MEASURES A.itemNo As AitemNo
PATTERN (A B* C+ D)
DEFINE B AS (B.SensorNo = A.SensorNo)
C AS (C.SensorNo <> A.SensorNo)
D AS (D.SensorNo = A.SensorNo AND D.Time-A.Time <= 1 Day) )
B* says that the item can stay in the original position for a while. Then it moves & it is detected other sensors (C*), until it returns to the original position (D)

8. Example 7: Coalescing Expressed using Kleene-closure
SELECT empno, first(B.start), max(B.end) FROM EmpTD AS PARTITION BY empno ORDER BY start AS PATTERN (B+) WHERE count(B.*)=1 OR B.start<=max(previous(B.end))