Informatica Senarios-1 by PenchalaRaju.Yanamala

1. I have a flat file, in which I have two fields, emp_id, emp_name. The data is like this- emp_id, emp_name soha101, ali101, kahn101 khan102, Siva102, shanker102, reddy.how to merge the names so that my output is like this Emp_id Emp_name101 Soha ali Kahn?

A:-In expression transformation use an output port ...in expression window write emp_id||empname

2. How to join a Flat and Relational Source without using (Joiner, Update, Lookup) transformations... is it possible? If yes i would like to know how?

A:- not possible

3. I have a source which relational, I am trying to populate to target flat file with one column for daily date which is sysdate, I want to populate the sysdate coulmn with DD/MM/YYYY format. Kindly provide a solution for this. My clear that my target is flat file.

A: - In expression transformation create one out put port, and write like: TO_DATE ('SYSDATE'.'DD/MM/YYYY').Connect this port to target.

4. If the source has duplicate records as id and name columns, values: 1 a, 1 b, 1 c, 2 a, 2 b, the target should be loaded as 1 a+b+c or 1 a||b||c, what transformations should be used for this?

A: - We need to use sorter, Expression and aggregator transformations to do this…..

1. Sort by ID2.Take 2 variable ports one for id and one for name and store the values of id and keep on comparing with current id i.e. variable is having previous id so if previous id=current id then (variable name)||name otherwise only name. Assign the variable name to output port3. Use aggregator and use last or max (len (name)) to get the result. 5. How many repositories can you create in informatica?

A-In Informatica 8.6.0 multiple repositories can be created under node. The domain can have multiple nodes.

6. Router T/R is active but some people are saying some times passive what is Reason behind that?

A: - First of all Every Active transformation is a Passive transformation, But every passive not Active.

In Router Transformation there is a special feature with Default group. Because of Default Group its passive. We can avoid this Default group by some transformation Settings, Now It’s Active.

7. I want to run an informatica workflow after completion of oracle procedure. That Procedure is not running through informatica and can be run at any Time in Database. Informatica is in windows environment. Is it possible? If yes please Explain?

A: - This can be possible with UNIX. Create a shell scripts which first has to Execute the Stored procedure or Package and we have command to check the completion or procedure After that use Pmcmd command in the same UNIX to start the workflow.

8. in a single mapping, more than 500 sources (legacy, VSAM, relational) will be loading into only one target. Whenever I retrieve the data (any record) from target, I need to find the details that the record belongs to which source?

A: - After every Source qualifier transformation just keep an Expression with flag.Dont go Single Source qualifier transformation. Keep 1 source qualifier Trans for one table.

9. Diff b/w Shortcut and reusable Object?

A: - A shortcut is created by assigning 'Shared' status to a folder within the Repository Manager and then dragging objects from this folder into another open folder

10. What is 'Power Center Pushdown Optimization Option' in INFORMATICA?(IMP)

A: - Pushdown optimization is used to push the complex logic to the database level. This will Reduce the complexity of the Power center mappings and increases the performance.

11. If no. of source columns is changing every time (First time it is 10 next time it is 20 so on). How to deal with it without changing mapping?

A: - If I understand this question properly, it says that the no. of "Source" columns are changing. I do not agree with this scenario. Probably in Data warehousing, you won't find such a design. As far as DWH is concerned, it takes the data from the OLTP systems & after performing some operations (E-extract, T- transform) it finally loads the data in some targets. Here, as per the question, the question itself arises for the OLTP design. No any OLTP (or database design principal) system suggests a varying number of columns. So, please do not get confused by such trivial kind of questions.DWH is a much disciplined subject & it follows a very good standards. Please go through the concepts first. You will get a clear picture of DWH then.

12. "Change cache" in Informatica?

A: - dynamic cache`13. Can we create index and drop index in existing table while using informatica?

A: - I know 4 ways in INFORMATICA

1) Source Analyzer window- (source table, Using key ports (enable, disable)). 2) Source qualifier Trans-(Sql override)3) Target override4) Pre sql, Post sql

14. If we are using an aggregator but forget to mention the group by port .what will be the Output?

A: - If we miss to enable any of the port as GROUP BY, the aggregator will write the lat row of the table to the next transformation.

15. There are n numbers of flat file of exactly same format are placed in a folder. Can we load these flat file’s data one by one to a single relational table by a Single session?

A: - Use source type as Indirect File Type and source file name as a file having the names of All the n flat files to be read.

15. Why do we go for update strategy TR in SCD rather using the session Properties?

A: - Session Properties like pre Source Rows INSERT, UPDATE, REJECT, DELETE, Using Session Properties we can do single flow only .SCD applicable for Insert, Update at a Time using Update Strategy Trans only. Using Update Trans we can create SCD mapping

16. How many mapplets u have created? And what is the logic used?

A: - We can create any No of Mapplets for 1 mapping. There is no limit for Mapplets. Every mapplet can have a Logic or logics,,,,,, There is no limit for logics.

17. LOOKUP Condition is nothing but a Join condition? What type of join condition it, By Default? Using the Lookup Condition How many types of relational conditions We can make?

A: - as per my understanding. Lkp is always behave like left outer join. It will give you all Matched records as well as unmatched records which are not present in base table...and Those unmatched records are will be null in case of unconnected lkp trn.....

18. What is Target Update Override? What is the Use?

A: - When we don't have primary keys defined on database level. And still we need update on This target from Informatica. We need to define keys at informatica level and use update Override in target property. This way we can update the table.

19. Why sequence generator should not directly connected to joiner transformation?

A:-Mainly sequence generator is used to generate a unique id dynamically. We can not join this number against any column in other tables...So. We can not connect sequence generator with joiner. And also, Main reason is joiner is an Active transformation. Means it can alter the number of rows. So, if u connect sequence generator with joiner the outcome sequence will not be proper.

20. from Source 100 rows are coming, on target there are 5 m rows which options is better to match data 1. Joiner 2 No cache 3. Static 4. Dynamic?

A: - Here we will use joiner for better performance. We will join the two sources making source table as master source. So only 100 comparisons will be done. So it will be very faster.

Whereas in static and dynamic we have to look up on the target which is very large 5m rows. So caching will take more time.

21. How to create a mapping? id date101 2/4/2008101 4/4/2008102 6/4/2008102 4/4/2008103 4/4/2008104 8/4/2008 O/P - should have only one id with the min (date) How to create a mapping for this?

A: - I think its Simple, with Agg Transformation, First Group by ID, Then go with min (date) in Same Agg Transformation.

22. What are set operators in Oracle?

A: - UNION, UNION ALL, MINUS and INTERSECT

23. How I can Schedule the Informatica job in "Unix Corn scheduling tool”?

A: - we can do this by using crontab file in UNIX, for this we need to schedule the Power centre job. or we can use "at" command in UNIX to schedule the job.

24. How can I generate Sequence Numbers to Target Table (with out using Sequence Gen Trans, Rank Trans).

A: - Use database Sequence generator call this from stored procedure or dummy lookup Query Or You can also use expression transformation. Create two ports one is variable And assign it to 0 and another one is output port and Write the logic to increment it (o_seq=v_Seq+1)

25. Can any one explain me step by step how scd will work?

Selects all rows. Caches the existing target as a lookup table. Compares logical key columns in the source against corresponding columns in the target lookup table. Compares source columns against corresponding target columns if key columns match. Flags new rows and changed rows. Creates two data flows: one for

new rows, one for changed rows. Generates a primary key for new rows. Inserts new rows to the target. Updates changed rows in the target, overwriting existing rows.

26. When we load flat files into target tables how do we identify duplicates? And where do load the duplicate records for further reference? How do we do chage data capture? Is this slowly changing Dimension technique?

A: - I have an idea after sql transformation go thruogh 2 Agg Trans, 2 Router Trans Agg1-gorup by col count=1 to router Trans Agg2-group by col count<>1 to router Trans (I think “it will help u”)

From 2nd router Transformation we have a Separate Target Table. Is this slowly changing Dimension technique? Change data capture (CDC) Mean newly Inserts, Updates Based on Data loading time, This Inserts, Updates only slowly changing Dimension technique.

27.I have table name called Team and I have name and DOJ in that table in oracle, when I retrieve the table in Informatica DOJ shows with date and time , I want want to know is it possible to get only date(MMDDYYYY) in the date data type,

A: - TO_CHAR (DOJ_port, 'MMDDYYYY')

28. How Union Transformation is an Active Trans?

A: - The simple logic of Union is that, It capture all the unique records from both the source. Suppose if you have 10 records in table A and 10 records in table B, in which 3 records Are same in both the tables. Then after using the Union transformation you will get 17 Records, as the records which are getting duplicated will not be in the output.29. How can we load first and last record from a flat file source to target?

A: - After sql Trans, go with AGG, RANK transformation, in RankTrans Properties set the rank 1 only---1 row returns, In AggTrans Don’t do any column for Group--Last row returns, We need 2 Target tables. 1 for 1st record,2 for last record, if u using the UNIONtrans one Target table is enough,,,

30. Diff B/W MAP Parameter, SESSION Parameter, Database connection session parameters? It’s possible to create 3parameters at a time? If Possible which one will fire FIRST?

A: - we can pass all these three types of parameters by using Perameterfile.we can declare all in one parameter file.A mapping parameter is set at the mapping level for values that do not change from session to session for example tax rates.Session parameter is set at the session level for values that can change from sesion to session, such as database connections for DEV, QA and PRD environments.The database connection session parameters can be created for all input fields to connection objects. For example, username, password, etc.It is possible to have multiple parameters at a time?The order of execution is wf/s/m.

31. How to run two workflow (not a sessions) sequentially, what is the process?

A: - The best way is obviously to run WF1 and then call WF2 using PMCMD command in the last session of WF1 (as a post session task).If you absolutely want to ensure that the second wf starts only after graceful completion of wf1 then simply add a command task for the pmcmd and use the piple to validate that the previous task is completed properly.OrWe can run the workflow sequentially .for that we need to write a ksh shell scripts or batch command and use cmd command 32. Which is costliest transformation? Costly means occupying more memory?

A:-Look up Transformation only, its going to maintain existing data also in cache memory

33. Which gives the more performance when compare to fixed width and delimited file? And why?

A: - fixed width, because there are no delimiters to check so the performance will increase.

34. How to list Top 10 salary, without using Rank Transmission?

A: - use sorter--> expression-->filter1) Sorter descend 2) use sequence generator connected expression to generator Sequence, 3) filter the value sequence number greater than 10

35. How to extract original records at one target & Duplicate records at one target?

A:- Source -> SQ -> Sorter ->Expression ->Router(or 2 filters) ->Targets

36. Is it possible to have "5 source & 5 Target" in single mapping?

A:-single mapping we can have 5 sources and 5 target and we need to arrange target load Plan if dependency exists.

37. without using Lookup & Sequence Generator, How to generate Sequence?

A:-using set count variable in expression transformation.

38. How to join 2 tables, without using any condition?

A:-Add dummy column in expression or Source Qul. For both source and use that column in Join condition.

39. Without source how to insert record to target?

A: - Without source you can not create mapping...

39. How will you remove the duplicate records from flat file without using sorter?

A: - Use aggregator transformation and group by all ports and create one port for checking Count...and pass the results accordingly to target tables.

40. How to join the two flat files using the joiner t/r if there is no matching port?

A:-Connect the source Qualifier of two different flat files to two different Exp Trans. Create a Dummy output port in both the exp trans. then using that port connects the joiner Tran.

41. What is the difference between Oracle performance and Informatica Performance? Which performance is better?

A:-oracle performance deals with the source &targets. Informatica performance deals with the Transformations. For efficiency result both are impotent...

42. How to run the batch using pmcmd command?

A:-Using Command task in the workflow

43. Suppose you have 2000 records in one table and 12000 in another which one you will consider as master and detail?

A:-We will consider the one with lesser number of records as master as with this approach the Data to be cached would have to be less and hence the performance can be improved. 44 .What is the target load order? 

A:-You specify the target load order based on source qualifiers in a maping.If you have the multiple source qualifiers connected to the multiple targets, you can designate the order in which informatica server loads data into the targets.

45. Explain use of update strategy transformation?

A:-To flag source records as INSERT, DELETE, UPDATE or REJECT for target database. Default flag is Inserting. This is must for Incremental Data Loading.OrThis is the important transformation, is used to maintain the history data or just most recent changes into the target table.We can set or flag the records by using these two levels.1) Within a session:-When you configure the session, you can instruct the informatica server to either treat all the records in the same way.2) Within a mapping:-within a mapping we use update strategy transformation to flag the records like insert, update, delete or reject.

46. This is a scenario in which the source has 2 cols -10 A ,10 A,20 C,30 D,40 E,20 CAnd there should be 2 targets one to show the duplicate values and another  target for distinct rows.T1 T210 A 10 A20 C 20 C30 D 40 E which transformation can be used to load data into target?

A:- 1.Sorce - Source qualifier – Target Check- Select distinct option 2.Source --Source qualifier- aggregator – Target group by-empno 3.Source --Source qualifier- sorter – Target Check- Select distinct option 4.Source -Source qualifier -Expression –Target -Source qualifier: check sorted by empno Expression:- port expression in_empno var-empno=var_duplicate var_duplicate=in_emp flag= IIF(var_duplicate=var_emp,'Y','N') 5.Source -Source qualifier -Rank-Expression -Target

47. What is parameter file? 

A:-When you start a workflow, you can optionally enter the directory and name of a parameter file. The Informatica Server runs the workflow using the parameters in the file you specify.  For UNIX shell users, enclose the parameter file name in single quotes:  -paramfile '$PMRootDir/myfile.txt

48. Difference between Rank and Dense Rank?

Rank:12<--2nd position2<--3rd position45Same Rank is assigned to same totals/numbers. Rank is followed by the Position. Golf game ususally Ranks this way. This is usually a Gold Ranking.Dense Rank:12<--2nd position2<--3rd position34Same ranks are assigned to same totals/numbers/names. the next rank follows the serial number.

49. What is the method of loading 5 flat files of having same structure to a single target and which transformations I can use? 

Two Methods.1.write all files in one directory then use file repository concept(dont forget to type source file type as

indirect in the session).2.use union t/r to combine multiple input files into a single target.

50. Suppose session is configured with commit interval of 10,000 rows and source has 50,000 rows. Explain the commit points for Source based commit and Target based commit. Assume appropriate value wherever required.

Source based commit will commit the data into target based on commit interval.so,for every 10,000 rows it will commit into target.

Target based commit will commit the data into target based on buffer size of the target.i.e., it commits the data into target when ever the buffer fills.Let us assume that the buffer size is 6,000.So,for every 6,000 rows it commits the data. ………..@...........

INFORMATACA FAQ’S & SENARIOS-2 By 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 CACHE ENABLED option check cheyyali. But by default it will be checked always.

5. session performance recovery has 3 flavours: 1. target lo commit ayyindi 2. when we use aggregator sorter trans then we cannot recover them back 3. 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 we call as server from this citrix server we click on VPN and we should enter the path and after entering path then we should enter port number [4 digits] and then we must enter the username and password. Now we are connected to server and we can get data what we want.

7. client daggara vunna server unix lo vuntundi, nuvvu ikkada nunchi akkada vunna data 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 load chesavu, now u want to load data to fact table then you use LOOKUP on SOURCE TABLE which is the target previously[dimension table].

12. Surrogate key generally system generated key but how does it created? Is there 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 tirigi manamu question veyyali. But the answer is NO.

15. In informatica 7.1.1 we can join heterogenous sources in joiner transformation where as in 6.1 we can join only homogeneous sources in joiner T/R. Also there is architecture difference between 6.1 and 7.1.1 But what 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 and you 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 approve your 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 THE FROM 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 your repository?

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

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

25. Differences between workflow and worklet is workflow can be scheduled where 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 an extension ".csv" and bring into source qualifier. This will be created in the form of flat files.

27. project architecture must know. what u will do in ur staging area. what u will do 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 the currval works or not?

ANS: Yes it works. nextval, currval both will generate keys. But currval=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 two types unique and non unique. Composite index means one index created on more ports.

Ex: create index indexname on table name <port1, port2, port3, port4>; We can increase performance of index using partitioning.

30. Difference between oracle 8i and 9i: merge, case, 999 columns we can create, grouping sets [rollup,cube], list partitioning, nvl2, coalesce, creating user defined datatypes, 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 records eventhough it acts as unionall.

33. we can use worklet with in a worklet. open the worklet designer and in tasks menu 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, audit dimensions. Degenerated: these dimensions identify operations transaction control number such as invoice [bill]. This exists only in fact table. Role playiing dimension: it occurs 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 metadata when 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 cannotbe accomodate by the natural granularity of single fact or dimension table. Servers bridge between the fact table and dimension table to allow many values of dimensions are ragged hierarchies.

38. U can use server grid to automate the distribution of session. it is a server object that distributes sessions in workflow to servers based on server availability. 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?

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 and peer review testing. Unit testing contains of two phases and they are test cases and test 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 the source = 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 can just run the session and change some values in tha mapping parameter instead of changing 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 parent table?

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 EMP GROUP BY EMPNO);

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 data techukuntamu,transformations develope chestamu, target lo insert chestamu, session run chestamu.

61. CLUSTER CURSOR DIFFERENCE BETWEEN PROCEDURES AND FUNCTIONS, 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 fact table to many dimension tables.

ANS: 50. I dont deal with all the sources as other team also use other sources. I didnot 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 join them?

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

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 could you 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 should execute. 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 master table records, so performance decreases. Similarly for master join it gives records which 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:

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 what T/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 can place anywhere according to your convinience.

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

ANS: COBOL.

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

Q) How many ways can you create ports?

ANS: In 2 ways. 1. Drag the port from another transforamtion 2. 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 sequence generator transformations, Pre or post session stored procedures, Target defintions, 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 into another 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 & stored procedure?

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 u have the multiple source qualifiers connected to the multiple targets, you can designate 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 relationship must exists between them.

Q) What is update strategy T/R?

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

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 treat a)all rows as insert b)all rows as update c)data driven (use instructions coded into the session mapping to flag rows for different database operations.) 2) within mapping :- You can flag rows for insert,update,delete or reject.Don't forget to set "Treat source rows as" to Data Driven in the session properties if you 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 for

sequential batch to start the sessions one after another.If you have several independent sessions you can use concurrent batches Which runs all the 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?

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 case of 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 new independent 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, Multidimensional metadata,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 you map three ports directly to the target?

ANS: No. Without having any common ports and unless we join them, we cannot directly 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 all data. 2. Inner join uses direct table name or alias name. But in outer join we will mandatorily give alias name for table name.Q) How to use sequence created in oracle in informatica?

ANS: No we cannot use.

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 use update 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 want them in multiple records so how many records we want that number we will give in 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 consistent patterns, trends and associations with in data stored in a data warehouse or other large databases. Ex: an insurance dataware house can be used to mine data for the most high risk People 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 we can 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 we can 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 the information where the session fail. In the bulk mode session recovery is not possible. 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?

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 into target?

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 perform bulk 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 mean in the source analyzer.

ANS: go to the cmd prompt and ftp the path of the unix box. Then use lcd command to go to the local current directory where u want to save the file.then use the put command 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 reusable transformation 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 the informatica server reads source data. Specify an outer join rather than the default inner join specify sorted records.Select only distinct values from the source. Creating custom query to issue a special SELECT statement for the informatica server to read source data.

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

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

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

ANS: NO. Informatica is not at all concern with back end database.It displays you all the information that is to be stored in repository.If want to reflect back end changes to informatica screens, again you have to import from back end to informatica by valid connection.And you have to replace the existing files with imported files.

Q) How can you recognise whether or not the newly added rows in the source r gets 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 newly added dimension in source will inserted into target with a primary key. Type2 Dimension/Flag current Maping: This maping is also used for slowly changing dimensions.In addition it creates a flag value for changed or new dimension. Flag indiactes the dimension is new or newlyupdated.Recent dimensions will gets saved with cuurent flag value 1. And updated dimensions r saved with the value 0.

Type2 Dimension/Effective Date Range Maping: This is also one flavour of Type2 maping used for slowly changing dimensions. This maping also inserts both new and changed dimensions in to the target. And changes r tracked by the 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 Rank transformation.The Informatica Server uses the Rank Index port to store the ranking position for each record in a group. For example, if you create a Rank transformation that ranks the top 5 salespersons for each quarter, the rank 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 inserting all rows. Use this mapping when you want to drop all existing data from your table before loading new data. Slowly Growing target : Loads a slowly growing fact or dimension table by inserting new rows. Use this mapping to load new data when existing data does not require updates.

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

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

Q) After draging the ports of three sources(sql server,oracle,informix) to a single 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 map them 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 the cache based on the amount you configure in the transformation or session properties. The informatica server stores condition values in the index cache and 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 need to connect it to a source qualifier transformation. The source qualifier transformation represnets the records that the informatica server reads when it runs 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 run recovery starting with the failed session. The Informatica Server completes the session and then runs the rest of the batch. Use the Perform Recovery session property To recover sessions in sequential batches configured to stop on failure: 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, the Informatica Server attempts to recover the previous session. If you do not configure a session in a sequential batch to stop on failure, and the remaining 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 parameters and maping variables. Parallel data processig: This feature is available for powercenter only.If we use the informatica server on a SMP system,yoU can use multiple CPU's to process a session concurently. Process session data using threads: Informatica server runs the session in two processes.

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 of file targets?

ANS: If you partition a session with a relational target informatica server creates multiple connections to the target database to write target data concurently.If you partition a session with a file target the informatica server creates one target file for 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 sorts session data using Binary sortorder. If you configure the seeion to use a binary sort order, the informatica server caluculates the binary value of each string and returns the 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 the session. The stored procedure issues a status code that notifies whether or not stored procedure completed sucessfully. This value can not seen by the user.It only used by the 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 to change between sessions such as database connections or source files. Server manager also allows U to create userdefined session parameters.Following are user defined session parameters. Database connections :location of Source file names: Use this parameter when u want to change the name or session source file between session runslocation of Target file name : Use this parameter when u want to change the name or session target file between session runs.location of Reject file name : Use this parameter when u want to change the name or 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 to truncate the target tables and run the session from the beginning. Run the session from the beginning when the Informatica Server cannot run recovery or when running recovery might result in inconsistent data.

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

ANS: Input group & Output group. The designer copies property information from the input ports of the input group to create a set of output ports for each output group. User defined groups & default group. you can not modify or delete default 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 incrementally and you can capture changes, you can configure the session to process only those changes. This allows the Informatica Server to update your target incrementally, rather than forcing it to process the entire source and recalculate the same calculations each time you run the session.

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

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

not achieve in source qualifier transformation. yoU need matching keys to join two relational sources in source qualifier transformation. Where as you doesn't need matching keys to join two sources. Two relational sources should come from same datasource in source qualifier. you can join relatinal sources which are coming from different sources also.

Q) If a session fails after loading of 10,000 records in to the target. How can you load 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 the charector data.You choose the data movement in the informatica server configuration settings.Two types of data movement modes avialable in informatica.ASCII mode and Uni code mode.

Q) How the informatica server increases the session performance through partitioning the source?

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

Q) What are the different threads in DTM process?

ANS: Master thread: Creates and manages all other threads Mapping thread: One maping thread will be creates for each session.Fectchs session and maping information. Pre and post session threads: This will be created to perform pre and post session operations. Reader thread: One thread will be created for each partition of a source.It reads data from source. Writer thread: It will be created to load data to the target.Transformation thread: It will be created to tranform data.

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 before running a session. A mapping parameter retains the same value throughout the entire session. When you use the maping parameter , yoU declare and use the parameter in a maping or maplet. Then define the value of parameter in a parameter file for the session. Unlike a mapping parameter, a maping variable represents a value that can change throughout the session. The informatica server saves the value of maping variable to the repository at the end of session run 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 the

lookup ports in the transformation. It compares the lookup transformation port values 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 the informatica 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 manually run the session. Different options of scheduling Run only on demand: server runs the session only when user starts session explicitly Run once: Informatica server runs the session only once at a specified date and time. Run every: Informatica server runs the session at regular intervels as u configured. Customized repeat: Informatica server runs the session at the dats and times secified in the repeat dialog box.

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 folder Or repository. But that target folder or repository should consists of mapping of that session. If target folder or repository is not having the maping of copying session ,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, and transform 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 Confirmed dimesion.

Q) Which kind of index is preferred in DWH?

ANS: we have bitmap index, b-tree index, function based index, reverse key index and 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 is normalized 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 a machine with multiple CPU's.

Q) Which tool you use to create and manage sessions and batches and to monitor 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 remote place, you need to configure database connection to the datasource. FileSource : To access the remote source file you must configure the FTP connection to the host machine before you create the session. Hetrogenous: When ur maping contains more than one source type,the server manager creates a hetrogenous session that displays source options for all 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 or pmcmd. These options are not available for batched sessions. 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 in Recovery 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 directly communicates the repository to check whether or not the session and users are valid. 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 DTM process.DTM is to create and manage the threads that carry out the session tasks.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 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 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 Sequence Generator transformation.

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

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

process. Locking and reading the session: When the informatica server starts a session lodamaager locks the session from the repository. Locking prevents U starting the session again and again.Reading the parameter file: If the session uses a parameter files,loadmanager reads the parameter file and verifies that the session level parematers are declared in the file.Verifies permission and privelleges: When the sesson starts load manger checks whether 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. 2.Two sources should have matching data types.

Q) How can u work with remote database in informatica? Did you work directly by 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 remote connections.Instead u bring that source into U r local machine where informatica server resides. If u work directly with remote source the session performance will decreases by passing less amount of data across the network in 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 the Informatica Server to either treat all records in the same way (for example, treat all records as inserts), or use instructions coded into the session mapping to flag records 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 strategy transformations with in the session mapping determine how to flag records for insert,update, delete or reject If you do not choose data driven option setting, the informatica server ignores all update strategy transformations in the mapping.

Q) What are the new features of informatica 7.1?

ANS: 1. Lookup on flat file is possible 2. Union Transformation is present 3. Version Control4. 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 the expensive joins and aggregates prior to execution and the result is stored in a

table in database and can refer to it in future. the adv of this is increse in performance. it works as snapshot. View is nothing but an sql query stored. it will not store data in tables.

Q) Can you use the maping parameters or variables created in one maping into any 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 repositories to create a data mart domain. In a data mart domain, you can create a single global repository to store metadata used across an enterprise, and a number of local 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 repository metadata. with a meta data reporter,you can access information about your repository with out having knowledge of sql,transformation language or underlying tables in the repository.

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

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 reads all the records from the master source and builds index and data caches based on the master rows.After building the caches, the Joiner transformation reads records 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 unique identifier or number (normally created by a database sequence generator ) for each record of a dimension table that can be used for the primary key to the table. 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 be sliced and diced. EX: A SALES cube can have PROFIT and COMMISSION measures and TIME, ITEM and 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 or overflowed.

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 drill down/drill across is the most basic requirement of an end user in a datawarehouse. Drilling down most directly addresses the natural end-user need to see more detail in an result. Drill down should be as generic as possible becuase there is absolutely no good way to predict users drill-down path.

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

ANS: Unlike most dimensions "Time dimension" do not change. You can populate it once 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 data stream that supports continuous, asynchronous, multi-point delivery of data. In a RTDW data moves straight from the source systems to decision makers without any form for staging.

Q) What is transitive dependency?

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

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

ANS: Data Warehouse Builder, Oracle Designer, Oracle Express, Express Objects etc.

Q) How to change value in persistant cache?

ANS: You can instruct the PowerCenter Server to rebuild the lookup cache if you need to by checking "Re-cache from lookup source option" in the lookup transformation properties tab.

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

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