34)What is aggregate cache in aggregator transforamtion?
When you run a workflow that uses an Aggregator transformation, the Informatica Server creates index and data caches in memory to process the transformation. If the Informatica Server requires more space, it stores overflow values in cache files.
35)Why you use repository connectivity?
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.
36)Briefly explian the Versioning Concept in Power Center 7.1.
When you create a version of a folder referenced by shortcuts, all shortcuts continue to reference their original object in the original version. They do not automatically update to the current folder version.
For example, if you have a shortcut to a source definition in the Marketing folder, version 1.0.0, then you create a new folder version, 1.5.0, the shortcut continues to point to the source definition in version 1.0.0. Maintaining versions of shared folders can result in shortcuts pointing to different versions of the folder. Though shortcuts to different versions do not affect the server, they might prove more difficult to maintain. To avoid this, you can recreate shortcuts pointing to earlier versions, but this solution is not practical for much-used objects. Therefore, when possible, do not version folders referenced by shortcuts.
37)What is source qualifier transformation?
When you add a relational or a flat file source definition to a mapping, you need to connect it to a Source Qualifier transformation. The Source Qualifier represents the rows that the Informatica Server reads when it executes a session. Join data originating from the same source database. You can join two or more tables with primary-foreign key relationships by linking the sources to one Source Qualifier.
Filter records when the Informatica Server reads source data. If you include a filter condition, the Informatica Server adds a WHERE clause to the default query. Specify an outer join rather than the default inner join. If you include a user-defined join, the Informatica Server replaces the join information specified by the metadata in the SQL query.Specify sorted ports. If you specify a number for sorted ports, the Informatica Server adds an ORDER BY clause to the default SQL query. Select only distinct values from the source. If you choose Select Distinct, the Informatica Server adds a SELECT DISTINCT statement to the default SQL query. Create a custom query to issue a special SELECT statement for the Informatica Server to read source data. For example, you might use a custom query to perform aggregate calculations or execute a stored procedure.
38)What is a source qualifier?-
When you add a relational or a flat file source definition to a mapping, you need to connect it to a Source Qualifier transformation. The Source Qualifier represents the rows that the Informatica Server reads when it executes a session.
39)What is source qualifier transformation?
When you add a relational or a flat file source definition to a maping,U need to connect it to a source qualifer transformation.The source qualifier transformation represnets the records that the informatica server reads when it runs a session.
40)What is incremantal aggregation?
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.
41)If you are workflow is running slow in informatica. Where do you start trouble
shooting and what are the steps you follow?
When the work flow is running slowly u have to find out the bottlenecks in this order target source mapping session system
42)What is exact use of 'Online' and 'Offline' server connect Options while defining
Work flow in Work flow monitor? . The system hangs when 'Online' server connect
option. The Informatica is installed on a Personal laptop.
When the repo is up and the PMSERVER is also up, workflow monitor always will be connected on-line. When PMserver is down and the repo is still up we will be prompted for an off-line connection with which we can just monitor the workflows
43)Explain about perform recovery?
When the Informatica Server starts a recovery session, it reads the OPB_SRVR_RECOVERY table and notes the row ID of the last row committed to the target database. The Informatica Server then reads all sources again and starts processing from the next row ID. For example, if the Informatica Server commits 10,000 rows before the session fails, when you run recovery, the Informatica Server bypasses the rows up to 10,000 and starts loading with row 10,001. By default, Perform Recovery is disabled in the Informatica Server setup. You must enable Recovery in the Informatica Server setup before you run a session so the Informatica Server can create and/or write entries in the OPB_SRVR_RECOVERY table.
44)How the informatica server sorts the string values in Ranktransformation?
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.
45)In which circumstances that informatica server creates Reject files?
When it encounters the DD_Reject in update strategy transformation.Violates database constraint Filed in the rows was truncated or overflowed.
46)How the informatica server sorts the string values in Ranktransformation?
When Informatica Server runs in UNICODE data movement mode ,then it uses the sort order configured in session properties.
47)What are the joiner caches?
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.
48)When do u we use dynamic cache and when do we use static cache in an connected
and unconnected lookup transformation
We use dynamic cache only for connected lookup. We use dynamic cache to check whether the record already exists in the target table are not. And depending on that, we insert,update or delete the records using update strategy. Static cache is the default cache in both connected and unconnected. If u select static cache on lookup table in infa, it own't update the cache and the row in the cache remain constant. We use this to check the results and also to update slowly changing records
49)What are variable ports and list two situations when they can be used?
We have mainly tree ports Inport, Outport, Variable port. Inport represents data is flowing into transformation. Outport is used when data is mapped to next transformation. Variable port is used when we mathematical caluculations are required. If any addition i will be more than happy if you can share.
50)How to load time dimension?
We can use SCD Type 1/2/3 to load any Dimensions based on the requirement.
51)where do we use MQ series source qualifier, application multi group source
qualifier. just give an example for a better understanding
We can use a MQSeries SQ when we have a MQ messaging system as source(queue).When there is need to extract data from a Queue, which will basically have messages in XML format, we will use a JMS or a MQ SQ depending on the messaging system. If you have a TIBCO EMS Queue, use a JMS source and JMS SQ and an XML Parser, or if you have a MQ series queue, then use a MQ SQ which will be associated with a Flat file or a Cobal file.
52)In a sequential Batch how can we stop single session?
We can stop it using PMCMD command or in the monitor right click on that perticular
session and select stop.this will stop the current session and the sessions next to it.
53)Can you start a session inside a batch idividually?
We can start our required session only in case of sequential batch.in case of concurrent
batch we cant do like this.
54)What is a view? How it is related to data independence?And what are the different
types of views,and what is Materialize view
view is a combination of one or more table.view does not stores the data,it just store the query in file format.If we excutes the query the query will fetch the data from the tables and just make it to view for us. Types views materilized view
55)What are various types of Aggregation?
Various types of aggregation are SUM, AVG, COUNT, MAX, MIN, FIRST, LAST,MEDIAN, PERCENTILE, STDDEV, and VARIANCE.
56)What is mystery dimention?
using Mystery Dimension ur maitaining the mystery data in ur Project.
57)what is the look up transformation?
Using it we can access the data from a relational table which is not a source in the mapping.
For Ex:Suppose the source contains only Empno, but we want Empname also in the mapping.Then instead of adding another tbl which contains Empname as a source ,we can Lkp the table and get the Empname in target.
58)How do you create a mapping using multiple lookup transformation?
Use unconnected lookup if same lookup repeats multiple times.
59)How can we eliminate duplicate rows from flat file?
Use Sorter Transformation. When you configure the Sorter Transformation to treat output
rows as distinct, it configures all ports as part of the sort key. It therefore discards
duplicate rows compared during the sort operation
60)How can you improve session performance in aggregator transformation?
Use sorted input.
61)What is the look up transformation?
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.
62)How to get two targets T1 containing distinct values and T2 containing duplicate
values from one source S1.
Use filter transformation for loading the target with no duplicates. and for the other
transformation load it directly from source.
63)How to delete duplicate rows in flat files source is any option in informatica
Use a sorter transformation , in that u will have a "distinct" option make use of it .
64)When we create a target as flat file and source as oracle.. how can i specify first rows as column names in flat files...
use a pre sql statement....but this is a hardcoding method...if you change the column
names or put in extra columns in the flat file, you will have to change the insert statement
65)Why did you use stored procedure in your ETL Application?
usage of stored procedure has the following advantages
1checks the status of the target database
2drops and recreates indexes
3determines if enough space exists in the database
4performs aspecilized calculation
66)why did u use update stategy in your application?
Update Strategy is used to drive the data to be Inert, Update and Delete depending upon some condition. You can do this on session level tooo but there you cannot define any condition.For eg: If you want to do update and insert in one mapping...you will create two flows and will make one as insert and one as update depending upon some condition.Refer : Update Strategy in Transformation Guide for more information
67)What r the options in the target session of update strategy transsformatioin?
Update as Insert:
This option specified all the update records from source to be flagged as inserts in the target. In other words, instead of updating the records in the target they are inserted as new records.
Update else Insert:
This option enables informatica to flag the records either for update if they are old or insert, if they are new records from source.
68)How do we do unit testing in informatica?
How do we load data in informatica ?
Unit testing are of two types
1. Quantitaive testing
2.Qualitative testing
Steps.
1.First validate the mapping
2.Create session on themapping and then run workflow.
Once the session is succeeded the right click on session and go for statistics tab. There you can see how many number of source rows are applied and how many number of rows loaded in to targets and how many number of rows rejected.This is called Quantitative testing.
If once rows are successfully loaded then we will go for qualitative testing.
Steps
1.Take the DATM(DATM means where all business rules are mentioned to the
corresponding source columns) and check whether the data is loaded according to the DATM in to target table.If any data is not loaded according to the DATM then go and check in the code and rectify it. This is called Qualitative testing. This is what a devloper will do in Unit Testing.
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