a interview faq's -2

8/14/2019 a Interview Faq's -2

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INFORMATACA FAQS & SENARIOS-2By PenchalaRaju.Yanamala

1. Slowly changing dimension by default it will take flag among flag, date, and version.In scd we will do only insert and update.

2. VPN: Virtual Private Network.

3. using update strategy t/r at mapping level and session level which scenarios do you

use this.

4. lookup lo sql override cheyyalantey compulsoriy gaa nuvvu LOOKUP CACHEENABLED option check cheyyali. But by default it will be checked always.

5. session performance recovery has 3 flavours:1. target lo commit ayyindi2. when we use aggregator sorter trans then we cannot

recover them back3. suppose the records that inserted into target are less then

we can truncate them.

6. After entring into company first you have to connect to server[Ex: CITRIX SERVER or TELLNET SERVER etc...]. citrix is software name but wecall as server from this citrix server we click on VPN and we should enter the pathand after entering path then we should enter port number [4 digits] and then wemust enter the username and password. Now we are connected to serverand we can get data what we want.

7. client daggara vunna server unix lo vuntundi, nuvvu ikkada nunchi akkada vunnadata unix command dwara ela techukuntavu.

8. Mana windows nunchi main server unix ki etla connect avutamu?

9. Apart from router can we create groups in any other transformation?

ANS: CUSTOM TRANSFORMATION.

10. Router transformation lo other than 0, 1, 2, 3 ee value pettinaa it just INSERTS.

Ex: 4,5,6....

11. When we do lookup on SOURCE?

Ex: nuvvu dimension table loki data loadchesavu, now u want to load data to fact table then you use LOOKUP onSOURCE TABLE which is the target previously[dimension table].

12. Surrogate key generally system generated key but how does it created? Isthere any option for it?

13. Normalizer transformation supports all data types.

14. We can edit reusable transformation?

ANS: U mean we will edit in transformation developer or in mapping designer ani tirigimanamu question veyyali. But the answer is NO.

15. In informatica 7.1.1 we can join heterogenous sources in joiner


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transformation where as in 6.1 we can join only homogeneous sources injoiner T/R. Also there is architecture difference between 6.1 and 7.1.1 Butwhat are they?

16. Peer reviews or code reviews both means same. Get full data regarding this.where do u store our bugs? If your team member did some mistake andyou found it then what you do?

17. unit test cases and test case documents who will write and how will you do

unit testing? what is the way you approach to do testing? who will approveyour test cases?

18. Normalizer also works for RELATIONAL DATABASES.

19. 3rd schema GALAXY , What is 4th schema FACT CONSTOLATION?

ANS: just like star and snow flake.

20. We can use views also instead of original table.

21. Inline view or inline query means IF ANY QUERY WHICH FOLLOW WITHIN THEFROM CLAUSE OF ANOTHER QUERY.

22. trigger is by default commit. we cannot keep commit in it.

23. How many repositories are there and what are the folders in yourrepository?

ANS: Developement, production, quality and assurance are the differentrepositiries we have.

24. Did you did any mappings? if yes then how did u did that and what is thedifficulty you faced in creating it.

25. Differences between workflow and worklet is workflow can be scheduledwhere as worklet cannot be scheduled and worklet depends on workflow to

run but with pmcmd command we can run WORKLET.

26. Excel sheets are first " file - save as" to CSV files i.e save the excel sheet with anextension ".csv" and bring into source qualifier. This will be created in the form offlat files.

27. project architecture must know. what u will do in ur staging area. what u willdo after staging area.

28. Sequence generator: CURRVAL=NEXTVAL + INCREMENT BY VALUE.

Q) Nuvvu oka target ki both nextval and currval ports attach chesavu then does thecurrval works or not?

ANS: Yes it works. nextval, currval both will generate keys. Butcurrval=nextval+increment by value.

29. Index: b-tree index is preferred for OLTP. bitmap index is used on static data[unchanged data] on DWH. bitmap is only of non unique index b-tree is of twotypes unique and non unique. Composite index means one index created on moreports.


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Ex: create index indexname on table name; We can increase performance of index usingpartitioning.

30. Difference between oracle 8i and 9i: merge, case, 999 columns we can create,grouping sets [rollup,cube], list partitioning, nvl2, coalesce, creating user defineddatatypes, multi table inserts.

31. sql: only once we can execute but in plsql we can execute many times.

sql we cannot stop the flow but in plsql we can stop the flow.sql we cannot manage errors but in plsql we can manage errors {raise_....}

32. whether union is active or passive?

ANS: It is ACTIVE t/r. because if we use primary key then it sorts some recordseventhough it acts as unionall.

33. we can use worklet with in a worklet. open the worklet designer and in tasksmenu click on insert worklet.

34. How do you load time dimension?

ANS: By using stored procedure.

35. what are dimension types?

ANS: confirmed, degenerated, scd, junk, causal, role playing, status, auditdimensions. Degenerated: these dimensions identify operations transaction controlnumber such as invoice [bill]. This exists only in fact table. Role playiing dimension: itoccurs when a physical dimension appears several times in a fact table, each

represented as a separate logical table with unique column with views.

status: whethe the transaction is success or fail it tells us.

audit: a physical dimension that tags each fact table row with operational metadatawhen the row is created.

36. what are differenty types of facts?

ANS: additive, semi additive, non additive, psuedo, textual, desired, year to date facts.

37. what is bridge table?

ANS: A table with multi part key capturing a many to many relationship that cannotbeaccomodate by the natural granularity of single fact or dimension table. Servers bridgebetween the fact table and dimension table to allow many values of dimensions areragged hierarchies.

38. U can use server grid to automate the distribution of session. it is a serverobject that distributes sessions in workflow to servers based on serveravailability. the grid maintains connections to multiple servers.

39. NOTE: u cannot run single session on multiple servers.

40. what is dead lock retry? how u use it?

41. what are the issues u faced while doing ur project?


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ANS: datatype mismatches, database connections, transformation errors,

42. How will u develope low level design documents?

43. What is the business logic of ur project?

ANS: U tell about client requirement.

44. What are the dimension tables and fact tables in ur project?

45. what is date format in ur project? what is the pk u used in it?

46. what is associated port in lookup transformation?

47. Have u done unit test plan [UTP] OR unit test specifications [UTS]?

ANS: There are 5 phases of test. unit testing, peer review testing, team leadtesting, system intergration, UAT or client testing. but we involve in unit testing andpeer review testing. Unit testing contains of two phases and they are test cases andtest script. In test cases we write columnid,source name,condition,target name, result,

expected result, remarks. In test script we write number of records in thesource = number of records in target.

ORACLE:

48. How will u connect to the servers?

49. What is the order of execution of ports that informatica server process?

ANS:

50. In which situation u used mapping variable and mapping parameters?

ANS: For example for daily update values we go for mapping variable so that we canjust run the session and change some values in tha mapping parameter instead ofchanging all the values.

51. What are different types of tasks? explain them.

52. what is referential integrity?

53. can we insert records into child table without the primarykey of the parenttable?

ANS: YES.

54. TO DISPLAY DUPLICATES IN ORACLE THE QUERY IS :

SELECT * FROM EMP WHERE ROWID NOT IN (SELECT MAX(ROWID) FROM

EMP GROUP BY EMPNO);

55. TO DELETE THE DUPLICATE ROWS FROM YOUR TABLE IS :

DELETE FROM EMP WHERE ROWID NOT IN (SELECT MAX(ROWID) FROM EMPGROUP BY EMPNO);


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56. Nuvvu chesina mappings ela pamputavu client ki?

ANS: Repository menu click on EXPORT OBJECTS.

57. Flat file is called as FEED FILE.

58. How do you get last record from flat file?

59. Differences between delimited and fixed width flatfiles?

ANS:

60. LOADING MANAMU CHEYYAMU KEVALAM source nunchi datatechukuntamu,transformations develope chestamu, target lo insertchestamu, session run chestamu.

61. CLUSTER CURSOR DIFFERENCE BETWEEN PROCEDURES ANDFUNCTIONS, IN PARAMETER AND OUT PARAMETERS IN PROCEDURES,PACKAGES, TRIGGERS.

62. TIME DIEMNSION BE CAREFUL.

63. DID U USED FACTLESS FACT TABLE IN UR PROJECT.

64. ONE TO MANY RELATION WE USED IN DATAWARE HOUSE. That is one facttable to many dimension tables.

ANS: 50. I dont deal with all the sources as other team also use other sources. Ididnot remember them.

Q) What is the size of your database in your project?

ANS: 1Terabyte.

Q) How many mappings you have done daily?

ANS: No i wont do a mapping daily. It may take one week or so to complete it.

Q) What is the size of the data extracts in the extraction process?

Q) How many measures you have created?

Q) How many measures are there in your fact table?

Q) What are relational sources?

Q) How can you identify your flat files?

Q) How can you call stored procedure?

ANS: In expression T/R we will call a stored procedure.

Q) We have 10 sources. Using joiner T/R how many joins you should use to jointhem?

ANS: Fundamental is n-1. So 10-1=9.


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Q) We have oracle as source and from this source we drag two tables EMP,DEPT and there is no common column for these two tables and how couldyou join them?

ANS: No we cannot join without having atleast one common port.

Q) There are 3 sessions, even though 2 sessions fails, my 3rd session shouldexecute. How do you build this?

Q) How many records you loaded into your project? How much time it takes?

ANS:

Q) Which join gives more performance and why?

ANS: Normal join. because normal join gives records which match the condition.Where as in case of detail join it gives records which match the condition plus mastertable records, so performance decreases. Similarly for master join it gives recordswhich match the condition plus detail table records, so performance decreeases.

Q) Is normal join = equi join or not?

ANS: Yes.

Q) Can you write SQL query in source qualifier transformation for flat files?

ANS: No

Q) What is passive T/R?

Q) What is the use of sorted input option? In which T/R can you useit?

ANS: Joiner, Aggregator, Source qualifier.

Q) What is the size of Aggregator data cache and index cache?

Q) What is transformation scope option in Aggregator T/R?

ANS: Transaction, All input.

Q) What are index and data cache?

Q) What are ports? How many types are they? Explain.

ANS: Input, Output, Lookup, Rank, Variable, return, groupby, master, in-out, key.

Q) How many transformations you should use in a mapplet?

ANS: Any number of transformations we can use.

Q) What is flatfile? What are the types of flatfiles?

ANS:Q) If you use a joiner T/R, what rules you should follow?

ANS:


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Q) How can you call a stored procedure in a lookup T/R?

ANS: No we cannot call a stored procedure in a lookup transformation.

Q) In which situation you will use a stored procedure?

Q) If you are using flatfile sources, how do you locate your flatfile?

ANS:

Q) Differences between Primary key and Unique key?

Q) How do test your code whether it is correct or wrong?

Q) Total how many mappings you have done in your company?

Q) How many workflows you have done in your company?

Q) Each mapping do you done? or any other have invovled in it?

ANS: No i myself will do mappings given to me.

Q) What is the rank data cache size and rank index cache size?

ANS: Data cache is twice the Index cache. Data cache = 2GB Index cache = 1GB.

Q) Expression condition?

Q) In joiner T/R how can you improve the performance?

ANS: By using sorted input, normal join condition we will use.

Q) Can you use active T/R in a mapplet?

ANS: Yes.

Q) From oracle database, we are importing 2 source tables and at that time whatT/R we should use?

ANS:

Q) What is cache directory? In which transformation we will use?

ANS: It is the directory where all the cache details are stored. It is $PMCachedir

Q) In a complex mapping how many transformations we will use?

ANS: Exactly we cannot say. But it will contain Lookup, Update strategy, Router,Stored procedure transformations in more number.

Q) Differences between primary key and foreign key?

Q) How many ways you can update relational sources and what are they?

Q) Where should you place the flatfile to import the flatfile to the designer?

ANS: It should be placed local to the server or if you can give exact path then you canplace anywhere according to your convinience.


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Q) To provide support for mainframes source data which files are used ofsource definitions?

ANS: COBOL.

Q) Which T/R should you need while using the gloabal sources as a sourcedefinition?

Q) How many ways can you create ports?

ANS: In 2 ways.1. Drag the port from another transforamtion2. Click the add buttion on the ports tab.

Q) What are the unsupported repositories for a mapplet?

ANS: COBOL source definition, Normalizer transformations, Non reusable sequencegenerator transformations, Pre or post session stored procedures, Targetdefintions, Power mart 3.5 style Look Up functions, XML source definitions,

IBM MQ source defintions.

Q) Can you use mappings parameter or variables created in one mapping intoanother mapping or mapplet?

ANS: No

Q) How can you improve session performance in Aggregator T/R?

ANS: By using incremental aggregation, by using sorted input.

Q) Why we use stored procedures?

ANS: For populating and maintaining databases.

Q) What are the types of data that passes between informatica server & storedprocedure?

ANS: Input and output parameters, Return value & Status code.

Q) What is target load order?

ANS: you specify the target load order based on source qualifiers in a maping. If uhave the multiple source qualifiers connected to the multiple targets, you candesignate the order in which informatica server loads data into the targets.

Q) What is the default join in source qalifier T/R?

Q) What are the basic needs to join two sources in source qualifier T/R?

ANS: The sources must be homogeneous. Primary key and Foreign key relationshipmust exists between them.

Q) What is update strategy T/R?

ANS: This transformation is used to maintain the history data or just most recentchanges in to target table.


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Q) What are two levels in update strategy T/R?

ANS: We can use update strategy at two different levels.1) within a session :- When you are configuring a session you can give

instructions to treata)all rows as insertb)all rows as update

c)data driven (use instructions coded into the session mapping to flag rowsfor different database operations.)

2) within mapping :- You can flag rows for insert,update,delete or reject.Don'tforget to set "Treat source rows as" to Data Driven in the session properties ifyou are flagging rows within the mapping.

Q) What is the default source option for update strategy T/R?

ANS: Data driven.

Q) What are the options in the target session of update strategy?

ANS: Insert, Delete, Update, Update as update, Update as insert, Update esle insert,Truncate table.

Q) Why do we use partitioning?

ANS: To improve session performance. We use partitoning in session.

Q) Can you copy the session to a different folder or repository?

ANS: Yes. But first we have to copy mappings then we can copy sessions.

Q) what is batch? Types of batches?

ANS: Grouping of session is known as batch. Batches are two types.Sequential: Runs sessions one after the other.Concurrent: Runs session at same time.If you have sessions with source-target dependencies you have to go forsequential batch to start the sessions one after another.If you haveseveral independent sessions you can use concurrent batches Which runs allthe sessions at the same time.

Q) Can you copy batch?

ANS: No.

Q) How many number of sessions that you can create in batch?

ANS: Any number of session we can run in a batch.

Q) What is the command that you use to run a batch?

ANS: pmcmd command.

Q) What are different options used to configure the sequential batches?

Q) In sequential batch can you run the session if previous session fails?


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ANS: Yes.By setting the option always runs the session.

Q) Can you start a session inside a batch individually?

ANS: We can start our required session only in case of sequential batch. But in caseof concurrent batch we cant do like this.

Q) Can you start a batch within a batch?

ANS: We cannot. If you want to start batch that resides in a batch,create a newindependent batch and copy the necessary sessions into the new batch.

Q) How can you stop or to run a batch?

ANS: By using pmcmd command or in server manager.

Q) What are the types of metadata that stores in repository?

ANS: Database connections, Global objects, Mappings, Mapplets, Multidimensionalmetadata,Reusable transformations, Sessions and batches, Short cuts, Source

definitions, Target definitions, Transformations.Q) What are the scheduling options to run a session?

Q) After dragging the ports of 3 sources to a single source qualifier can youmap three ports directly to the target?

ANS: No. Without having any common ports and unless we join them, we cannotdirectly map the ports from source qualifier to target.

Q) Can you use a flatfile in a mapplet?

ANS: Yes

Q) What are the metadata that a catalog stores?

Q) Types of catalog? This is cognos question.

Q) Can we have multiple conditions in a lookup?

ANS: Yes.

Q) Can we have multiple conditions in a filter T/R?

ANS: No.

Q) How the flags are called in update strategy T/R?

ANS: We call them in form of strings or numerics.Q) Differences between inner and outer join?

ANS: 1. Inner join gives rows which match the condition where as outer join gives alldata.

2. Inner join uses direct table name or alias name. But in outer join we willmandatorily give alias name for table name.

Q) How to use sequence created in oracle in informatica?

ANS: No we cannot use.


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Q) What are types of caches in informatica?

ANS: Index cache and data cache.

Q) What are minimum and maximum values for index and data cache?

ANS:

Q) What is the size of your repository?

Q) How many source tables you have?

Q) Can you update the target at session level also? If yes then why do we useupdate strategy T/R?

ANS:

Q) How separate 1:30 to 3:00 'o clock we have maintainance the internal time?

Q) What is the difference between local repository and global repository?

Q) How you use email task?

ANS: Email task send email when the workflow is success or fail.

Q) What is normalizer transformation? Why are we using 'occurs' in this T/R?

ANS: In our cobol sources we are having single source records but we wantthem in multiple records so how many records we want that number we will givein the 'occurs' option.

Q) Differences between connected and unconnected lookup?

Q) What is data mining?

ANS: Data Mining is an analytic process designed to explore hidden consistentpatterns, trends and associations with in data stored in a data warehouse orother large databases.

Ex: an insurance dataware house can be used to mine data for the most high riskPeople to insure in a certain geographical area.

Q) What is difference between normal load and bulk load?

ANS: In the normal mode the data loading into the target in row by row basis and wecan see the information in session log file in row by row. If it fails the session,then use the session recovery option in the session properties. Then again wecan run the session. Also the target table contains indexes, check constraints,primary key, foreign keys then you go for normal loading. In the bulk load,loading the data into the target in group of rows and we can't see theinformation where the session fail. In the bulk mode session recovery is notpossible. We can improve the session performance. Whenever you perform the

data loading in bulk mode the target database table [oracle,sybase,SQL server]doesnot contain indexes, primary key, check constraints and foreign keys.

Q) What is difference between parameter and variable?

Q) How will you delete duplicate rows in a flatfile?


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ANS: By using "distinct" option in sorter transformation we can delete duplicate rows.

Q) In the update strategy T/R how to use delete option in session properties?

Q) What are the advantages of datamarts?

Q) How to get particular records [Ex: 3rd, 5th, 8th} from a flatfile to load intotarget?

Q) What is external loading? What is incremental loading?

ANS: 1) External loading is done by SQL loader. SQL loader is a tool used to performbulk loading. 2)

Q) Where you use decode function?

ANS: We use in expression T/R. decode(status,'m','marriage','u','unmarried)

Q) Explain the differences of the following DWH & OLAP, DWH & ODS, ODS &OLTP, OLTP & DWH, OLTP & DSS.

Q) How do you Import the flat file that is on the Informatica Unix server? I meanin the source analyzer.

ANS: go to the cmd prompt and ftp the path of the unix box. Then use lcd commandto go to the local current directory where u want to save the file.then use the putcommand to copy the file to the local directory.

Q) What are the out put files that the informatica server creates during the

session running?

ANS: Informatica server log, Session log, session detail file, performance detail file,reject file, control file, post session email, indicator file, output file, cache file.

Q) What is difference between maplet and reusable transformation?

ANS: Mapplet consists of set of transformations that is reusable. A reusabletransformation is a single transformation that can be reusable.

Q) What are the tasks that source qualifier performs?

ANS: Join data originating from same source data base.Filter records when theinformatica server reads source data. Specify an outer join rather than the

default inner join specify sorted records.Select only distinct values from thesource. Creating custom query to issue a special SELECT statement for theinformatica server to read source data.

Q) How many ways you can update a relational source defintion and what arethey?

ANS: 1. Edit the definition 2. Reimport the defintion.

Q) If i done any modifications for my table in back end does it reflect ininformatca warehouse or maping desginer or source analyzer?

ANS: NO. Informatica is not at all concern with back end database.It displays you all


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the information that is to be stored in repository.If want to reflect back endchanges to informatica screens, again you have to import from back end toinformatica by valid connection.And you have to replace the existing files withimported files.

Q) How can you recognise whether or not the newly added rows in the source rgets insert in the target ?

ANS: In the Type2 maping we have three options to recognise the newly added rows

1. Version number 2. Flagvalue 3. Effective date Range.

Q) What are the different types of Type2 dimension maping?

ANS: source will gets inserted in target along with a new version number. And newlyadded dimension in source will inserted into target with a primary key.

Type2 Dimension/Flag current Maping: This maping is also used for slowlychanging dimensions.In addition it creates a flag value for changed or newdimension. Flag indiactes the dimension is new or newlyupdated.Recentdimensions will gets saved with cuurent flag value 1. And updated dimensions rsaved with the value 0.

Type2 Dimension/Effective Date Range Maping: This is also one flavour ofType2 maping used for slowly changing dimensions. This maping also insertsboth new and changed dimensions in to the target. And changes r tracked bythe effective date range for each version of each dimension.

Q) what are the transformations that restricts the partitioning of sessions?

ANS: Advanced External procedure tranformation and External procedure transformation: This transformation contains a check box on the

properties tab to allow partitioning. Aggregator Transformation: If you use sorted ports you cannot parttion the

assosiated source. Normalizer Transformation and XML targets.

Q) When the informatica server marks that a batch is failed?

ANS: If one of session is configured to "run if previous completes" and that previous

session fails.

Q) What is the Rankindex in Ranktransformation?

ANS: The Designer automatically creates a RANKINDEX port for each Ranktransformation.The Informatica Server uses the Rank Index port to store theranking position for each record in a group. For example, if you createa Rank transformation that ranks the top 5 salespersons for each quarter, therank index numbers the salespeople from 1 to 5.

Q) What is the default join that source qualifier provides?

ANS: Inner equi join.

Q) What are the types of mapping in Getting Started Wizard?

ANS:Simple Pass through maping : Loads a static fact or dimension table by


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inserting all rows. Use this mapping when you want to drop all existing datafrom your table beforeloading new data.Slowly Growing target : Loads a slowly growing fact or dimension table byinserting new rows. Use this mapping to load new data when existing datadoes not require updates.

Q) How can you create or import flat file definition in to the warehousedesigner?

ANS: Yes we can create flat file in warehouse designer.

Q) After draging the ports of three sources(sql server,oracle,informix) to asingle source qualifier, can you map these three ports directly to target?

ANS: NO.Unless and until u join those three ports in source qualifier you cannot mapthem directly.

Q) what is meant by lookup caches?

ANS: The informatica server builds a cache in memory when it processes the first

row af a data in a cached look up transformation. It allocates memory for thecache based on the amount you configure in the transformation or sessionproperties. The informatica server stores condition values in the index cacheand output values in the data cache.

Q) What are the different options used to configure the sequential batches?

ANS: 1.Run the session only if previous session completes sucessfully.2. Always runs the session.

Q) What is source qualifier transformation?

ANS: When you add a relational or a flat file source definition to a maping, you needto connect it to a source qualifier transformation. The source qualifiertransformation represnets the records that the informatica server reads when itruns a session.

Q) How can you recover the session in sequential batches?

ANS: If you configure a session in a sequential batch to stop on failure, you can runrecovery starting with the failed session. The Informatica Server completes thesession and then runs the rest of the batch. Use the Perform Recovery session

property To recover sessions in sequential batches configured to stop onfailure:1.In the Server Manager, open the session property sheet.2.On the Log Files tab, select Perform Recovery, and click OK.3.Run the session.4.After the batch completes, open the session property sheet.5.Clear Perform Recovery, and click OK.If you do not clear Perform Recovery, the next time you run the session, theInformatica Server attempts to recover the previous session.If you do not configure a session in a sequential batch to stop on failure, and theremaining sessions in the batch complete, recover the failed session as a

standalone session.

Q) What are the new features of the server manager in the informatica 5.0?

ANS: you can use command line arguments for a session or batch.This allows you to change the values of session parameters,and mapping


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parameters and maping variables. Parallel data processig: This feature isavailable for powercenter only.If we use the informatica server on a SMPsystem,yoU can use multiple CPU's to process a session concurently.Process session data using threads: Informatica server runs the session in twoprocesses.

Q) What is transformation?

ANS: A Transformation is a type of metadata object which is responsible fo

transforming the data or processing the data.

Q) What is difference between partioning of relatonal target and partitioning offile targets?

ANS: If you partition a session with a relational target informatica server createsmultiple connections to the target database to write target data concurently.Ifyou partition a session with a file target the informatica server creates one target filefor each partition. you can configure session properties to merge these target files.Q) What are the different types of schemas?

ANS: two types of schemas r there: Star schema and snow flake Schema.

Q) How the informatica server sorts the string values in Rank transformation?

ANS: When the informatica server runs in the ASCII data movement mode it sortssession data using Binary sortorder. If you configure the seeion to use a binary sortorder, the informatica server caluculates the binary value of each string and returnsthe specified number of rows with the higest binary values for the string.

Q) What is the status code?

ANS: Status code provides error handling for the informatica server during thesession. The stored procedure issues a status code that notifies whether or not storedprocedure completed sucessfully. This value can not seen by the user.It only used bythe informatica server to determine whether to continue running the session or stop.

Q) What are session parameters?

ANS: Session parameters r like maping parameters,represent values U might want tochange between sessions such as database connections or source files. Servermanager also allows U to create userdefined session parameters.Following are user

defined sessionparameters. Database connections :location of Source file names: Use this parameter when u want to change thename or session source file between session runslocation of Target file name : Use this parameter when u want to change the nameor session target file between session runs.location of Reject file name : Use this parameter when u want to change the nameor session reject files between session runs.

Q) How can you complete unrecoverable sessions?

ANS: Under certain circumstances, when a session does not complete, you need totruncate the target tables and run the session from the beginning. Run thesession from the beginning when the Informatica Server cannot run recovery orwhen running recovery might result in inconsistent data.

Q) What are types of groups in Router T/R?


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ANS: Input group & Output group. The designer copies property information from theinput ports of the input group to create a set of output ports for each outputgroup. User defined groups & default group. you can not modify or deletedefault groups.

Q) What is incremental aggregation?

ANS: When using incremental aggregation, you apply captured changes in the source

to aggregate calculations in a session. If the source changes only incrementallyand you can capture changes, you can configure the session to process onlythose changes.

This allows the Informatica Server to update your target incrementally, rather thanforcing it to process the entire source and recalculate the same calculations each timeyou run the session.

Q) What are the diffrences between joiner transformation and source qualifiertransformation?

ANS: You can join hetrogenious data sources in joiner transformation which we can

not achieve in source qualifier transformation. yoU need matching keys to jointwo relational sources in source qualifier transformation. Where as you doesn'tneed matching keys to join two sources. Two relational sources should comefrom same datasource in source qualifier. you can join relatinal sources whichare coming from different sources also.

Q) If a session fails after loading of 10,000 records in to the target. How can youload the records from 10001 th record when u run the session next time?

ANS: By using session recovery.

Q) What are the data movement modes in Informatica?

ANS: Data movement modes determines how informatcia server handles thecharector data.You choose the data movement in the informatica server configurationsettings.Two types of data movement modes avialable in informatica.ASCII mode andUni code mode.

Q) How the informatica server increases the session performance throughpartitioning the source?

ANS: For a relational sources informatica server creates multiple connections for eachparttion of a single source and extracts seperate range of data for eachconnection. Informatica server reads multiple partitions of a single sourceconcurently. Similarly for loading also informatica server creates multipleconnections to the target and loads partitions of data concurently. For XML andfile sources,informatica server reads multiple files concurently. For loading thedata informatica server creates a seperate file for each partition(of a sourcefile).U can choose to merge the targets.

Q) What are the different threads in DTM process?

ANS:Master thread: Creates and manages all other threadsMapping thread: One maping thread will be creates for each session.Fectchssession and maping information.Pre and post session threads: This will be created to perform pre and postsession operations. Reader thread: One thread will be created for each


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partition of a source.It reads data from source. Writer thread: It will be createdto load data to the target.Transformation thread: It will be created to tranformdata.

Q) Define mapping and session.

ANS: Mapping: It is a set of source and target definitions linked by transformation

objects that define the rules for transformation. Session : It is a set of instructions that describe how and when to move data

from source to targets.

Q) What are mapping parameters and mapping variables?

ANS: Maping parameter represents a constant value that you can define beforerunning a session. A mapping parameter retains the same value throughout theentire session. When you use the maping parameter , yoU declare and use theparameter in a maping or maplet. Then define the value of parameter in aparameter file for the session. Unlike a mapping parameter, a maping variable

represents a value that can change throughout the session. The informaticaserver saves the value of maping variable to the repository at the end of sessionrun and uses that value next time yoU run the session.

Q) What is lookup T/R? What is default T/R for Lookup T/R?

ANS: Use lookup transformation in u'r mapping to lookup data in a relational table,view, synonym. Informatica server queries the look up table based on thelookup ports in the transformation. It compares the lookup transformation portvalues to lookup table column values based on the look up condition. The

default T/R for lookup T/R is Target.

Q) What is polling?

ANS: It displays the updated information about the session in the monitor window.The monitor window displays the status of each session when U poll theinformatica server.

Q) What are the types of Joins in Informatica?

ANS: Normal, Master outer, Detail outer, Full outer.

Q) What are the scheduling options to run a sesion?

ANS: you can shedule a session to run at a given time or intervel,or u can manuallyrun the session. Different options of scheduling Run only on demand: serverruns the session only when user starts session explicitlyRun once: Informatica server runs the session only once at a specified dateand time.

Run every: Informatica server runs the session at regular intervels as uconfigured.Customized repeat: Informatica server runs the session at the dats and times

secified in the repeat dialog box.


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Q) Can you copy the session to a different folder or repository?

ANS: Yes. By using copy session wizard u can copy a session in a different folderOr repository. But that target folder or repository should consists of mapping ofthat session. If target folder or repository is not having the maping of copyingsession ,you should have to copy that maping first before u copy the session.

Q) What are two types of processes that informatica runs the session?

ANS:Load manager Process: Starts the session, creates the DTM process,and sends post-session email when the session completes.

DTM process: Creates threads to initialize the session, read, write, andtransform data, and handle pre- and post-session operations.

Q) What is confirmed dimension and fact?

ANS: A dimension which links with more than one fact table is called as Confirmeddimesion.

Q) Which kind of index is preferred in DWH?

ANS: we have bitmap index, b-tree index, function based index, reverse key indexand composit index. we will use bitmap index in DWH.

Q) What are the designer tools for creating tranformations?

ANS: Mapping designer,Tansformation developer, Mapplet designer.

Q) What is operational data source (ODS)? .

ANS: This is the data base used to captur daily business activites and this isnormalized databse.

Q) To achieve the session partition what r the necessary tasks u have to do?

ANS: Configure the session to partition source data. Install the informatica server on amachine with multiple CPU's.

Q) Which tool you use to create and manage sessions and batches and tomonitor and stop the informaticaserver?

ANS: Informatica server manager.

Q) How can you access the remote source into your session?

ANS:Relational source: To acess relational source which is situated in a remoteplace, you need to configure database connection to the datasource.

FileSource : To access the remote source file you must configure the FTPconnection to the host machine before you create the session.

Hetrogenous: When ur maping contains more than one source type,the servermanager creates a hetrogenous session that displays source options forall types.

Q) What is Standalone session? How to recover the standalone session?

ANS: A standalone session is a session that is not nested in a batch.If a standalone session fails, you can run recovery using a menu command orpmcmd. These options are not available for batched sessions.


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To recover sessions using the menu:1. In the Server Manager, highlight the session you want to recover.2. Select Server Requests-Stop from the menu.3. With the failed session highlighted, select Server Requests-Start Session inRecovery Mode from the menu.To recover sessions using pmcmd:1.From the command line, stop the session.2. From the command line, start recovery.

Q) Why you use repository connectivity?

ANS: When you edit, schedule the sesion each time, informatica server directlycommunicates the repository to check whether or not the session and users arevalid. All the metadata of sessions and mappings will be stored in repository.

Q) What is DTM process?

ANS: After the loadmanger performs validations for session,it creates the DTMprocess.DTM is to create and manage the threads that carry out the sessiontasks.I creates the master thread.Master thread creates and manges all the

other threads.

Q) In which conditions we can not use joiner transformation (Limitaions ofjoiner 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 Normalizer transformation.Both input pipelines originate from the same Joiner transformation.Either input pipelines contains an Update Strategy transformation.

Either input pipelines contains a connected or unconnected SequenceGenerator transformation.

Q) What are the tasks that Loadmanger process will do?

ANS: Manages the session and batch scheduling: When you start the informaticaserver the load maneger launches and queries the repository for a list ofsessions configured to run on the informatica server. When u configure thesession the loadmanager maintains list of list of sessions and session starttimes. When u sart a session loadmanger fetches the session information fromthe repository to perform the validations and verifications prior to starting DTM

process.Locking and reading the session: When the informatica server starts asession lodamaager locks the session from the repository. Locking prevents U

starting the session again and again.Reading the parameter file: If the session uses aparameter files,loadmanager reads the parameter file and verifies that the sessionlevel parematers are declared in the file.Verifies permission and privelleges: When the sesson starts load manger checkswhether or not the user have privelleges to run the session.Creating log files: Loadmanger creates logfile contains the status of session.

Q) what are the settiings that u use to cofigure the joiner transformation?

ANS: 1.Master and detail source 2.Type of join 3.Condition of the join.

Q) What are the basic needs to join two sources in a source qualifier?

ANS: 1.Two sources should have primary and Foreign key relation ships.


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2.Two sources should have matching data types.

Q) How can u work with remote database in informatica? Did you work directlyby using remote connections?

ANS: To work with remote datasource u need to connect it with remote connections.But it is not preferable to work with that remote source directly by using remoteconnections.Instead u bring that source into U r local machine whereinformatica server resides. If u work directly with remote source the session

performance will decreases by passing less amount of data across the networkin a particular time.

Q) Describe two levels in which update strategy transformation sets?

ANS: Within a session: When you configure a session, you can instruct theInformatica Server to either treat all records in the same way (for example, treatall records as inserts), or use instructions coded into the session mapping to flagrecords for different database operations. Within a mapping: Within a mapping,you use the Update Strategy transformation to flag records.

Q) What is Datadriven?

ANS: The informatica server follows instructions coded into update strategytransformations with in the session mapping determine how to flag records forinsert,update, delete or reject If you do not choose data driven option setting,the informatica server ignores all update strategy transformations in themapping.

Q) What are the new features of informatica 7.1?

ANS: 1. Lookup on flat file is possible 2. Union Transformation is present 3. VersionControl4. LDAP Authentication 5. supporting of 64mb architecture.

Q) What are the basic needs to join two sources in a source qualifier?

ANS: 1) Both sources should be from same Database.2) They should have a common field which can be used for a join.

Q) What is the difference between view and materialised view?

ANS: View - store the SQL statement in the database and let you use it as a table.

Every time you access the view, the SQL statement executes.Materialized view - Materialized view can be used to precalculate theexpensive joins and aggregates prior to execution and the result is stored in atable in database and can refer to it in future. the adv of this is increse inperformance. it works as snapshot. View is nothing but an sql query stored. itwill not store data in tables.

Q) Can you use the maping parameters or variables created in one maping intoany other reusable transformation?

ANS: Yes. Because reusable tranformation is not contained with any maplet or

maping.

Q) What is power center repository?

ANS: The PowerCenter repository allows you to share metadata across repositoriesto create a data mart domain. In a data mart domain, you can create a single


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global repository to store metadata used across an enterprise, and a number oflocal repositories to share the global metadata as needed.

Q) What is metadata reporter?

ANS: It is a web based application that enables you to run reports againist repositorymetadata. with a meta data reporter,you can access information about yourrepository with out having knowledge of sql,transformation language orunderlying tables in the repository.

Q) What is the filename which you need to configure in UNIX while installinginfromatica?

ANS: pmserver.cfg OR In informatica 7, under $PMRootDir there is one utility (script)called pmconfig exist, through it we can configure the inforamtica.

Q) What are the joiner caches?

ANS: When a Joiner transformation occurs in a session, the Informatica Server readsall the records from the master source and 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.

Q) What is a surrogate key?

ANS: A surrogate key is a substitution for the natural primary key. It is a uniqueidentifier or number (normally created by a database sequence generator ) foreach record of a dimension table that can be used for the primary key to thetable. A surrogate key is useful because natural keys may change.

Q) What is a Cube?

ANS: A multi-dimensional representation of data in which the cells contain measures(i.e. facts) and the edges represent data dimensions by which the data can besliced and diced.

EX: A SALES cube can have PROFIT and COMMISSION measures and TIME, ITEMand REGION dimensions.

Q) In which circumstances that informatica server creates Reject files?

ANS: 1. When it encounters the DD_Reject in update strategy transformation.2. Violates database constraint. 3. Filed in the rows was truncated oroverflowed.

Q) What are the tools in informatica?Why we are using that tools?

ANS: Powermart and powercenter are the popular tools.1. Powercenter is generally used in production environment.2. powermart is generally used in developement environment.

Q) What are the most important features of a data warehouse?

ANS: DRILL DOWN, DRILL ACROSS and TIME HANDLING. To be able to drilldown/drill across is the most basic requirement of an end user in adatawarehouse. Drilling down most directly addresses the natural end-userneed to see more detail in an result. Drill down should be as generic as


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possible becuase there is absolutely no good way to predict users drill-downpath.

Q) What the easiest way to build a corporate specific time dimension?

ANS: Unlike most dimensions "Time dimension" do not change. You can populate itonce and use for years. So the easiest way is to use spread-sheet.

Q) What is a Real-Time Data Warehouse - RTDW?

ANS: Real Time Data warehous is an analytic component of an enterprise level datastream that supports continuous, asynchronous, multi-point delivery of data. Ina RTDW data moves straight from the source systems to decision makerswithout any form for staging.

Q) What is transitive dependency?

ANS: When a non-key attribute identifys the value of another non-key atribute thenthe table is set to contain transitive dependecncy.

Q) What oracle tools are available to design and build a data warehosue/datamart?

ANS: Data Warehouse Builder, Oracle Designer, Oracle Express, Express Objectsetc.

Q) How to change value in persistant cache?

ANS: You can instruct the PowerCenter Server to rebuild the lookup cache if youneed to by checking "Re-cache from lookup source option" in the lookup

transformation properties tab.

Q) Without using sequence generator transformation can we create sequencegenerator?

ANS: Yes. In lookup transformation by using ASSOCIATED PORT column.

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