February 20, 2013 at 7:33 am
Hi,
I have one table called Student. The source for loading the table is StudentHistory.
My Scenario is i have a single student having multiple records like single student mapped to several departments.
Select distinct student,Department from Student gives 10 records.
if i get 11th record from StudentHistory table it should check for student mapped to that department, if no add record to Student table.
I applied Left outer join using mergejoin task in SSIS for this scenario.
StudentHistory as left source and Student as right, when i am looking for the student & department, for matched rows also my Student table is returning null values.
so that all the 11 records are getting inserted into Student table based on condition.
What is the reason for retrieving all null values even for matched records?
February 20, 2013 at 8:40 am
I could take a guess at what you want and I might nail it but I might not. So in the spirit of getting you some tested code in an efficient way I would prefer you provide examples of the tables you are using in the form of CREATE TABLE statements, a set of sample data in the form of INSERT statements, the expected results based on that sample data and most importantly, what you have tried so far.
There are no special teachers of virtue, because virtue is taught by the whole community.
--Plato
February 21, 2013 at 1:10 am
Hi, Thanks for the reply
here goes the example
Source Table
CREATE TABLE StudentHistory(
StudentHistoryId int IDENTITY(1,1) NOT NULL,
StudentId VARCHAR(6) NOT NULL,
DepartmentId VARCHAR(5) NOT NULL,
ProcessedMonth INT NOT NULL,
ProcessedYear INT NOT NULL,
ProcessedDate DATETIME NOT NULL,
InsertedDate DATETIME NOT NULL
CONSTRAINT PK_StudentHistory_StudentHistoryId PRIMARY KEY CLUSTERED
(
StudentHistoryId ASC
)WITH (IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]
Considerations
1) StudentId and DepartmentId are foreign Keys
2) Every month for a year will have present active records
3) ProcessedDate is daily process time getdate
4) InsertedDate is the record first time inserted for that month in a year
DestinationTable
CREATE TABLE Student(
PrimarykeyId int IDENTITY(1,1) NOT NULL,
StudentId VARCHAR(6) NOT NULL,
DepartmentId VARCHAR(5) NOT NULL,
InsertedDate DATETIME NOT NULL,
LastUpdated DATETIME NOT NULL
CONSTRAINT PK_StudentHistory_PrimarykeyId PRIMARY KEY CLUSTERED
(
PrimarykeyId ASC
)WITH (IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]
Consider like Student 1 is mapped to three departments in both the tables
for today history table is inserted with same student mapped to another department.
Student table lookup for student and department when left outer join is performed the matched three records are also returning null
February 21, 2013 at 3:57 am
Thank you for the table definitions. This looks like homework, which is fine, I am happy to help, but I need for you to provide the other three things I asked for.
There are no special teachers of virtue, because virtue is taught by the whole community.
--Plato
February 21, 2013 at 6:12 am
INSERT INTO StudentHistory(1,100,2,2013,GETDATE(),'2013-02-01 12:00:00 ')
INSERT INTO StudentHistory(2,100,2,2013,GETDATE(),'2013-02-01 12:00:00 ')
INSERT INTO StudentHistory(2,101,2,2013,GETDATE(),'2013-02-01 12:00:00 ')
INSERT INTO StudentHistory(2,102,2,2013,GETDATE(),'2013-02-01 12:00:00 ')
INSERT INTO StudentHistory(2,103,2,2013,GETDATE(),'2013-02-01 12:00:00 ')
INSERT INTO StudentHistory(3,103,2,2013,GETDATE(),'2013-02-01 12:00:00 ')
INSERT INTO StudentHistory(3,104,2,2013,GETDATE(),'2013-02-01 12:00:00 ')
INSERT INTO StudentHistory(1,100,'2013-02-01 12:00:00 ','2013-02-01 12:00:00 ')
INSERT INTO StudentHistory(2,100,'2013-02-01 12:00:00 ','2013-02-01 12:00:00 ')
INSERT INTO StudentHistory(2,101,'2013-02-01 12:00:00 ','2013-02-01 12:00:00 ')
INSERT INTO StudentHistory(2,102,'2013-02-01 12:00:00 ','2013-02-01 12:00:00 ')
INSERT INTO StudentHistory(2,103,'2013-02-01 12:00:00 ','2013-02-01 12:00:00 ')
INSERT INTO StudentHistory(3,103,'2013-02-01 12:00:00 ','2013-02-01 12:00:00 ')
Try to insert this first later build ssis to perform left outer join with StudentHistory as Left source and Student as right Source on conditions studentid and departmentid. I have used Merge join
Now INSERT INTO StudentHistory(2,104,2,2013,GETDATE(),GETDATE())
run the ssis my issue is i am doing lookup for a studentid 2 to a department while doing so i should get the below data
Source Destination
StudentIdDepartmentId StudentIdDepartmentId
2 100 2100
2 101 2101
2 102 2102
2 103 2103
2 104 NULLNULL
but i am receiveing
Source Destination
StudentIdDepartmentId StudentIdDepartmentId
2 100 NULLNULL
2 101 NULLNULL
2 102 NULLNULL
2 103 NULLNULL
2 104 NULLNULL
Could u please guide me on this
February 21, 2013 at 6:26 am
Than you for the test data. There were some errors in it but I got it to work. Here it is for other onlookers:
INSERT INTO dbo.StudentHistory
(StudentId, DepartmentId, ProcessedMonth, ProcessedYear, ProcessedDate, InsertedDate)
VALUES (1, 100, 2, 2013, GETDATE(), '2013-02-01 12:00:00 '),
(2, 100, 2, 2013, GETDATE(), '2013-02-01 12:00:00 '),
(2, 101, 2, 2013, GETDATE(), '2013-02-01 12:00:00 '),
(2, 102, 2, 2013, GETDATE(), '2013-02-01 12:00:00 '),
(2, 103, 2, 2013, GETDATE(), '2013-02-01 12:00:00 '),
(3, 103, 2, 2013, GETDATE(), '2013-02-01 12:00:00 '),
(3, 104, 2, 2013, GETDATE(), '2013-02-01 12:00:00 ');
INSERT INTO dbo.Student
(StudentId, DepartmentId, InsertedDate, LastUpdated)
VALUES (1, 100, '2013-02-01 12:00:00 ', '2013-02-01 12:00:00 '),
(2, 100, '2013-02-01 12:00:00 ', '2013-02-01 12:00:00 '),
(2, 101, '2013-02-01 12:00:00 ', '2013-02-01 12:00:00 '),
(2, 102, '2013-02-01 12:00:00 ', '2013-02-01 12:00:00 '),
(2, 103, '2013-02-01 12:00:00 ', '2013-02-01 12:00:00 '),
(3, 103, '2013-02-01 12:00:00 ', '2013-02-01 12:00:00 ');
I am wondering if you need to bother with any of the Join Transforms in SSIS. Are StudentHistory and Student tables on the same Database Instance, i.e. can they be joined together in a single SQL query like this to add missing rows to the Student table?
INSERT INTO dbo.Student
(
StudentId,
DepartmentId,
InsertedDate,
LastUpdated
)
SELECT DISTINCT
sh.StudentId,
sh.DepartmentId,
GETDATE(),
GETDATE()
FROM dbo.StudentHistory sh
LEFT JOIN dbo.Student s ON sh.StudentId = s.StudentId
AND sh.DepartmentId = s.DepartmentId
WHERE s.StudentId IS NULL;
There are no special teachers of virtue, because virtue is taught by the whole community.
--Plato
May 16, 2013 at 3:32 pm
So you are adding back records to the student table that you think should be there. Could it be the students table was archived somewhere else and the history table not? By reinserting the student you may be duplicating data relative to the student and (possible) student archive tables. Just a thought that occurred to me.
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