what is the diff b/w union and joiner and lookup?
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Answer / raveendra guturi
Union: while we have to join two sources should data
structure same.
)Joiner is active transformation
Lookup is a passive transformation
2)In joiner we can join two heterogeneous sources for
entire Records based on a condition.
But in look up only the first value or last value of the
Records will be passed if more records matched with that
condition. So only one value will be returned to the
transformation.
3)If we need entire values we must go for joiner. Take that
look up table as source and use joiner. No alternative
Solution.
4) Joiner operates on source
Lookup operates on source and target level
5) Joiner does not support non-eqijoin its support equijoin.
Lookup supports non-equijoin
6) Joiner doesnot match for null values
Lookup supports null values
7) join supports only = operator
Lookup supports <=,>=,=,1= operators
9) Joiner supports outer join but lookup doesnot.
| Is This Answer Correct ? | 8 Yes | 1 No |
Answer / maruthi
union-can join two tables without common port
joiner-can join any two hetrogenous sources,but common port
is necessary.
lookup-we can join two tables by using sql over-ride,apart
from that we can check wether the row is already existing
or not.
| Is This Answer Correct ? | 6 Yes | 1 No |
Answer / rajesh myle
1. Lookup T/R supports Non-Equi Joins. Where as Joiner
T/R does not support the Non Equi Joins. (Joiner T/R
supports only Equi Joins(i.e. ‘=’))
| Is This Answer Correct ? | 5 Yes | 3 No |
Answer / subh
In case multiple rows are expected in the joining
condition, joiner has to be used. As look up wont be able
to return multiple rows.
| Is This Answer Correct ? | 0 Yes | 0 No |
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