Friday, November 14, 2008

Questions VI

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.

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.

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.
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

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.

How to load time dimension?
We can use SCD Type 1/2/3 to load any Dimensions based on the requirement.
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.

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.

Can you start a session inside a batch idividually?
We can start our required session only in case of sequential case of concurrent batch we cant do like this.

What is a view? How it is related to data independence?And what are the different types of views,and what is Materialize view views 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

What are various types of Aggregation?
Various types of aggregation are SUM, AVG, COUNT, MAX, MIN, FIRST, LAST, MEDIAN, PERCENTILE, STDDEV, and VARIANCE.

What is mystery dimention?
using Mystery Dimension ur maitaining the mystery data in ur Project.

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.

How do you create a mapping using multiple lookup transformation?
Use unconnected lookup if same lookup repeats multiple times.

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

How can you improve session performance in aggregator transformation?
Use sorted input.

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.

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.

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 .
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

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

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