why union transformation is active transformation?
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Answer / mahaboob basha
Hi,
the only condition for a transformation to bcum active is
row number changes.
Now the thing is how a row number can change. Then there are
2 conditions:
1. either the no of rows coming in and going out is diff.
eg: in case of filter we have the data like
id name dept row_num
1 aa 4 1
2 bb 3 2
3 cc 4 3
and we have a filter condition like dept=4 then the o/p wld
b like
id name dept row_num
1 aa 4 1
3 cc 4 2
So row num changed and it is an active transformation
2. or the order of the row changes
eg: when Union transformation pulls in data, suppose we have
2 sources
sources1:
id name dept row_num
1 aa 4 1
2 bb 3 2
3 cc 4 3
source2:
id name dept row_num
4 aaa 4 4
5 bbb 3 5
6 ccc 4 6
it never restricts the data from any source so the data can
come in any manner
id name dept row_num old row_num
1 aa 4 1 1
4 aaa 4 2 4
5 bbb 3 3 5
2 bb 3 4 2
3 cc 4 5 3
6 ccc 4 6 6
so the row_num are changing . Thus we say that union is an
active transformation
| Is This Answer Correct ? | 12 Yes | 2 No |
Answer / raji
Hai frnds,
According to my knoweledge,active t/f means which changes the number of rows that can pass through it.
coming to why union t/s is active.......because union t/f merges the data which is coming from two sources,it means that it summarizes the data which is passing through union t/f,with this the no.of rows coming from that will be less....
so it is an active t/f...
Thanks.....Raji
| Is This Answer Correct ? | 3 Yes | 16 No |
Answer / hanumantharao
Active transformation means recieve n number of records and
return < or > that of n number of records.
Union transformation is Active transformation because it
return less than that of recieved records.
| Is This Answer Correct ? | 1 Yes | 26 No |
If the source1 has 10 records and the it contains 3 records
and the same 3 records are in the second source,the second
source contains 10 records if we want to join them using union
t/r then the output is 17 records instead of 20 records.
thats why we say that UNION T/R is active t/r
| Is This Answer Correct ? | 3 Yes | 32 No |
Answer / sony
actually union transformation is a passive
transformation,not an active transformation.
| Is This Answer Correct ? | 1 Yes | 30 No |
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