What is lookup transformation and when is it used?
Lookup transformation is used to look up a source, source qualifier, or target to get the relevant data. It is a kind of join operation in which one of the joining tables is the source data, and the other joining table is the lookup table.
Why unconnected lookup is passive?
Unconnected lookup cannot insert values into lookup cache file as it is not possible to find out from which part of the mapping flow and the transformation that is called from and how many number of times that is called.
What is the difference between active and passive transformations?
A transformation can be active or passive. An active transformation can change the number of rows that pass through the transformation. A passive transformation does not change the number of rows that pass through the transformation. …
What are the types of lookup transformation?
Types of Lookup Transformations
- Connected or Unconnected: They differ in the way output is received.
- Lookup via Flat File or Relational: After creating Lookup Transformation we can lookup either on a Flat file or on relational tables.
- Cached or Uncached :
What is the difference between Joiner and lookup transformation in Informatica?
A joiner is used to join data from different sources. lookup is used to get related values from another table or check for updates etc in the target table.
Which is better lookup or joiner in Informatica?
In case of Flat file, generally, sorted joiner is more effective than lookup, because sorted joiner uses join conditions and caches less rows. In case of database, lookup can be effective if the database can return sorted data fast and the amount of data is small, because lookup can create whole cache in memory.
What is normalizer transformation in Informatica?
The Normalizer transformation is an active transformation that transforms one incoming row into multiple output rows. When the Normalizer transformation returns multiple rows from an incoming row, it returns duplicate data for single-occurring incoming columns.
What is the difference between connected lookup and UnConnected lookup?
Connected lookup receives input values directly from mapping pipeline, whereas UnConnected lookup receives values from the lookup expression from another transformation. Connected lookup caches all lookup columns, whereas UnConnected lookup caches only the lookup output and lookup conditions.
Is router active or passive transformation?
The Router transformation is an active transformation that you can use to apply a condition to incoming data. passes the row multiple times. You can either drop rows that do not meet any of the conditions or route those rows to a default output group.
Why Union is an active transformation?
Union is an active transformation because it combines two or more data streams into one.
What are the two types of lookups?
There are two forms of Lookup: Vector and Array. The vector form of the LOOKUP function will search one row or one column of data for a specified value and then get the data from the same position in another row or column.
How many types of lookups are there in Informatica?
Types of Lookup Caches in Informatica
| Lookup Caches in Informatica | Static cache |
|---|---|
| Dynamic cache | |
| Shared cache | |
| Persistent cache |
Is the lookup transformation passive or active in Java?
This is the passive transformation which allows performing the lookup on the flat files, relational table, views, and synonyms. When we configure the Lookup transformation to return multiple rows, the Lookup transformation is an active transformation. The lookup transformation supports horizontal merging, such as equijoin and nonequijoin.
Which is the result of the lookup transformation?
The Lookup transformation returns the result of the lookup to the target or another transformation. We can configure the Lookup transformation to return a single row or multiple rows. This is the passive transformation which allows performing the lookup on the flat files, relational table, views, and synonyms.
Is the sentence in the past tense or passive?
The sentence is in Simple Past Tense. (Passive) Direction: In the following questions the sentences have been given in Active/Passive voice. From the given alternatives, choose the one which best expresses the given sentence in Passive/Active voice. You should follow all the instructions carefully.
Can you return multiple rows from a lookup transformation?
You cannot use dynamic cache for Lookup transformation that returns multiple rows. You cannot return multiple rows from an unconnected Lookup transformation. You can configure multiple Lookup transformations to share a named cache if the Lookup transformations have matching caching lookup on multiple match policies.