Informatica FAQs - Total 111 FAQs

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  • 7/31/2019 Informatica FAQs - Total 111 FAQs

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    Informatica FAQ

    Q1. While importing the relational source definition from database,what are the metadata of source you import?Ans:

    Source name. Database location. Column names. Data types. Key constraints.

    Q2. How many ways you can update a relational source definition andwhat are they?Ans:

    Two ways1. Edit the definition2.

    Re-import the definition

    Q3. Where should you place the flat file to import the flat file definitionto the designer?Ans: Place it in local folder

    Q4. To provide support for Mainframes source data, which files areused as a source definitions?Ans: COBOL files

    Q5. Which transformation should you need while using the COBOLsources as source definitions?

    Ans:Normalizer transformation which is used to normalize the data.

    Since COBOL sources are oftenly consists of De-normalized data.

    Q6. How can you create or import flat file definition in to thewarehouse designer?Ans:

    You can not create or import flat file definition in to warehousedesigner directly. Instead you must analyze the file in sourceanalyzer, then drag it into the warehouse designer. When youdrag the flat file source definition into warehouse designer

    workspace, the warehouse designer creates a relational targetdefinition not a file definition. If you want to load to a file,configure the session to write to a flat file. When the Informaticaserver runs the session, it creates and loads the flat file.

    Q7. What is the mapplet?

    Ans:Mapplet is a set of transformations that you build in the mappletdesigner and you can use in multiple mappings.

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    Q8. What is a transformation?Ans:

    It is a repository object that generates, modifies or passes data.

    Q9. What are the designer tools for creating transformations?Ans:

    Mapping designer Transformation developer Mapplet designer

    Q10. What are the active and passive transformations?Ans:

    An active transformation can change the number of rows thatpass through it. A passive transformation does not change thenumber of rows that pass through it.

    Q11. What are the connected or unconnected transformations?Ans:

    An unconnected transformation is not connected to othertransformations in the mapping. Connected transformation isconnected to other transformations in the mapping.

    Q12. How many ways you create ports?Ans:

    Two ways1. Drag the port from another transformation.2. Click the add button on the ports tab.

    Q14. What are the reusable transformations?Ans:

    Reusable transformations can be used in multiple mappings.When you need to incorporate this transformation into mapping,

    you add an instance of it to mapping. Later if you change thedefinition of the transformation, all instances of it inherit thechanges. Since the instance of reusable transformation is apointer to that transformation, you can change thetransformation in the transformation developer, its instancesautomatically reflect these changes. This feature can save yougreat deal of work.

    Q15. What are the methods for creating reusable transformations?Ans:

    Two methods1. Design it in the transformation developer.2. Promote a standard transformation from the mappingdesigner. After you add a transformation to the mapping, youcan promote it to the status of reusable transformation.

    Once you promote a standard transformation to reusablestatus, you can demote it to a standard transformation at anytime.

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    If you change the properties of a reusable transformation inmapping, you can revert it to the original reusabletransformation properties by clicking the revert button.

    Q16. What are the unsupported repository objects for a mapplet?Ans:

    COBOL source definition. Joiner transformations. Normalizer transformations. Non reusable sequence generator transformations. Pre or post session stored procedures. Target definitions. Power mart 3.5 style Look Up functions. XML source definitions. IBM MQ source definitions.

    Q17. What are the mapping parameters and mapping variables?Ans:

    Mapping parameter represents a constant value that you candefine before running a session. A mapping parameter retains thesame value throughout the entire session.When you use the mapping parameter, you declare and use theparameter in a mapping or mapplet. Then define the value ofparameter in a parameter file for the session.Unlike a mapping parameter, a mapping variable represents avalue that can change throughout the session. The Informaticaserver saves the value of mapping variable to the repository at theend of session run and uses that value next time you run thesession.

    Q18. Can you use the mapping parameters or variables created in onemapping into another mapping?Ans:

    NO, we can use mapping parameters or variables in anytransformation of the same mapping or mapplet in which youhave created mapping parameters or variables.

    Q19. Can you use the mapping parameters or variables created in one

    mapping into any other reusable transformation?Ans:

    Yes, because reusable transformation is not contained with any

    mapplet or mapping.

    Q20. How can you improve session performance in aggregatortransformation?Ans:

    Use sorted input.

    Q21. What is aggregate cache in aggregator transformation?Ans:

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    The aggregator stores data in the aggregate cache until itcompletes aggregate calculations. When you run a session thatuses an aggregator transformation, the Informatica server createsindex and data caches in memory to process the transformation.If the Informatica server requires more space, it stores overflowvalues in cache files.

    Q22. What are the difference between joiner transformation andsource qualifier transformation?Ans:

    You can join heterogeneous data sources in joiner transformationwhich we can not achieve in source qualifier transformation.You need matching keys to join two relational sources in sourcequalifier transformation. Where as you doesn't need matching

    keys to join two sources.Two relational sources should come from same datasource insource-qualifier. You can join relational sources which are comingfrom different sources also.

    Q23. In which conditions we can not use joiner transformation(Limitations of joiner transformation)?Ans:

    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 Normalizertransformation.

    Both input pipelines originate from the same Joinertransformation.

    Either input pipelines contains an Update Strategytransformation.

    Either input pipelines contains a connected or unconnectedSequence Generator transformation.

    Q24. What are the settings that you use to configure the joinertransformation?Ans:

    Master and detail source Type of join Condition of the join

    Q25. What are the join types in joiner transformation?Ans:

    Normal (Default) Master outer Detail outer Full outer

    Q26. What are the joiner caches?Ans:

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    When a Joiner transformation occurs in a session, theInformatica Server reads all the records from the master sourceand builds index and data caches based on the master rows.After building the caches, the Joiner transformation readsrecords from the detail source and perform joins.

    Q27.what is the look up transformation?

    Ans:Use lookup transformation in your mapping to lookup data in arelational table, view and synonym.Informatica server queries the look up table based on the lookupports in the transformation. It compares the lookuptransformation port values to lookup table column values basedon the look up condition.

    Q28. Why use the lookup transformation ?Ans:

    To perform the following tasks.

    Get a related value. For example, if your source table includesemployee ID, but you want to include the employee name in

    your target table to make your summary data easier to read.

    Perform a calculation. Many normalized tables include valuesused in a calculation, such as gross sales per invoice or salestax, but not the calculated value (such as net sales).

    Update slowly changing dimension tables. You can use aLookup transformation to determine whether records alreadyexist in the target.

    Q29. What are the types of lookup?Ans:

    Connected and Unconnected

    Q30. Differences between connected and unconnected lookup?Ans:

    Connected Lookup Unconnected Lookup

    1. Receives input values directly fromthe pipe line.

    1. Receives input values from theresult of a lkp expression in aanother transformation.

    2. You can use a dynamic or staticcache.

    2. You can use a static cache.

    3. Cache includes all lookup columns

    used in the mapping.

    3. Cache includes all lookup out

    put ports in the lookup conditionand the lookup/return port.

    4. Support user defined defaultvalues.

    4. Does not support user defineddefault values.

    Q31. Difference between static cache and dynamic cacheAns:

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    Static cache Dynamic cache

    1. You can not inert or update thecache.

    1. You can insert rows into thecache as you pass to the target.

    2. The Informatic

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