Frequently Asked Questions

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1) Difference between connected and unconnected transformations?

Connected transformation is connected to another transformation with in a mapping.

Unconnected transformation is not connected to any transformation with in a mapping.


2) In which conditions we cannot use joiner transformation(limitations of joiner transformation)?

Both pipelines begin with the same original data source.

Both input pipelines originate from the same source qualifier transformation.

Both input pipelines originate from the same normalizer transformation

Both input pipelines originate from the same joiner transformation.

Either input pipelines contains an update strategy transformation

Either input pipelines contains sequence generator transformation.


3) what are the settings that u use to configure the joiner transformation?

Master and detail source.

Type of join

Condition of the join


4) what is look up transformation?

look up transformation can be used in a table view based on condition by default lookup is left outer join.


5) why use the lookup transformation?

To perform the following tasks.

Get a related value.For example if your table includes employee ID,but you want to include such as gross sales per invoice or sales tax but not the calculated value(such as net sales).

Update slowly changing dimension tables. You can use a lookup transformation to determine whether records already exist in the target.


6) What are the types of lookup?

Connected and unconnected


7) Difference between connected and unconnected lookup?

Connected lookup	Unconnected lookup
Receives input values directly from the pipe line.	Receives input values from the result of a clkp expression in a another transformation.
U can use a dynamic or static Cache	U can use a static cache
Cache includes all lokkup columns used in the mapping(that is lookup table columns included in the lookup condition and lookup table columns linked as output ports to other transformations)	Cache includes all lookup/output ports in the lookup condition and the lookup/return port.
Can return multiple columns from the same row or insert into the dynamic lookup cache.	Designate one return port(R).Returns one column from each row.
If there is no match for the lookup condition, the informatica server returns the default value for all output ports.If u configure dynamic caching the informatica server inserts rows into the cache.	If there is no matching for the lookup condition the informatica server returns NULL
Pass multiple output values to another transformatnion.Link lookup/output ports to another transformation	Pass one output value to another transformation.The lookup/output/return port passes the same value to the ---------------------------------------------------------

Supports user-defined default values.	Does not support user-defined default values.

8)explain index cache and data cache?

The informatica server stores conditions values in the index cache and output values in the data cache.

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