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Fact table size calculation
How to calculate fact table size.........and how to find fact granularity? Please tell me answers to these 2 questions..
n.sriramk
- Nov 5th, 2010
Size= Number of expected records * E (sum of all columns data type size) bytes
divakar021
- Oct 7th, 2010
A Fact table is calculated based on "lowest level granualarity". The lowest level granualarity can be determined from the ...
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Error Handling
How will you perform error handling in Informatica? What do you do with the bad files etc?
shr_4
- Oct 27th, 2010
Go to session log file and see no. of affected rows, applied rows and rejected rows. According to that you can know if any error occured. ?If any error occurs you can check why it occured and correct it accordingly.
Rajan Raorane
- Oct 21st, 2010
Use of Router Transformation and differentiate the bad file from the Required ones..hence further you can post the same in One Table
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Remove Mapping Duplicate Values
How to remove duplicate values in mapping?
abhiora24
- Oct 26th, 2010
If Source is Flat File then useSORTER transformation/Aggregator transformationIf Source is RDBMS then useAggregator transformation
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Star Schema
One fact table is surrounded by only one dimension table. Is it star schema or not? Give any real time example?
Rajan Raorane
- Oct 21st, 2010
Fact table surronded by Dimension table in which Dimension table must have primary key and fact table must include foriegn key
srikanthsanga
- Sep 23rd, 2010
Star schema doesn't mean that it has to be surrounded with dimension tables it depends on whether the dimension table have any more relation table to it if it has then it becomes a snow flake schema otherwise its considered as star schema
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Can we create duplicate rows in star schema?
Rajan Raorane
- Oct 21st, 2010
No as Star Schema Includes combination Dimension table and fact table in which we already defined the Primary and foriegn key....Hence No ques of Duplicate Rows.
Ashwani
- Oct 25th, 2006
Duplicate row has nothing to do with StarSchema. StarSchema is mathodoly and Duplicate row is part of actual implementation in DB. If u look at Surrogate key conceot then "NO" beside surrogate key oth...
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Hi everyone,can anyone explain error handling in informatica with examples so that it will be easy to explain the same in the interview.
Rajan Raorane
- Oct 21st, 2010
Scenario in which when a load of 1000 records is loaded into the target and 100 records are bad records, those hundred goes to badfile dir which mention Session and the rest of the 900 should load to ...
sreenivasareddy.aug10
- Jul 10th, 2009
Error HandlingSometimes a stored procedure returns a database error, such as “divide by zero” or “no more rows”. The final result of a database error during a stored procedure ...
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Single Level Transformation
Why single level and nested expressions is not supported in same Aggregation transformation?
gopalzoro
- Oct 20th, 2010
If an Aggregator transformation contains a single-level function in any output port, you cannot use a nested function in any other port in that transformation. When you include single-level and nested...
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What is the architecture of any Data warehousing project? what is the flow?
jayapraveen
- Oct 18th, 2010
architecture is like1. Source Systems: Like Mainframe,Oracle,People soft,DB2.2. Landing tables: These are tables act like source. Usedfor easy to access, for backup purpose, as reusable forother mappi...
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What is surrogate key ? how many surrogate key used in ur dimensions?
jayapraveen
- Oct 14th, 2010
SURROGATE KEY IS NOTHING BUT WHAT A PRIMARY KEY IS USED IN AN TRANSACTION DATABASE ,GENERALLY THIS COME IN PICTURE WHEN THE DATA IS UPDATING REGULARLY IN THE TABLE THIS MAKES THE TABLE INCONSISTENT SO...
sn3508
- Oct 25th, 2006
Surrogate key or warehouse key acts like a composite primary key. If the target doesn't have a unique key, the surrogate key helps to address a particular row. It is like a primary key in the target.
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In Source Qualifier and in Target I have 1,2,3 row and I want to insert 4,5 records in source and I want them in target also? What is the procedure to load them?
jayapraveen
- Oct 14th, 2010
I think this can be done by incremental aggregation at source side and target side
sanjeev
- Aug 6th, 2007
I have one more idea. I think it is right.In source qualifier we have a pre SQL and post SQL. using the pre SQL we can insert 4 and 5 records there.Sanjeev
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If a record with 40 data type size from oracle& 100 from siebel (source) but target data type size is 50 , then how informatica server handles this situation?
shiva4mba
- Oct 13th, 2010
As per my knowledge the session will run successfully and the records with different datatype sizes will be skipped.This is in oracle and I am not sure about siebel.Thankx
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How to retrieve distinct records from 'flatfile' source ?
HP Interview Question - How to retrieve only distinct record from 'flatfile' source, without using sorter transformation? Is it possible? How?
shiva4mba
- Oct 13th, 2010
Yes it is possible Use aggregator after the source qualifierand put all the ports as group byit will give distinct records only
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Check Record History
How do you check if a record is a history record or a fresh record?
shiva4mba
- Oct 13th, 2010
As per my knowledge take a lookup on the target and check with their warehouse keys in the lookup condition
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1)how can we delete the cache files while we using aggregator transformaation?2)exlain about cache files handling in informatica3) there are two flat files and the two flat files contain two fileds as states.both the flat files contain duplicates how to eliminate this duplicates?4) can we use lookup transformation with out using source qualifier transformation?
jayapraveen
- Oct 13th, 2010
1.I think DTM remes the Cache files after successful loading the data into target2.a.persistent cache b.staic cache c.shared cache d.dynamic cache3.sorter befo...
chandrarekha
- Sep 28th, 2007
After the session executes,??DTM removes?the cache memory and deletes cachefiles Incase of persistant cache and incremtal aggregation cache files are saved.Generally cache files are created in Info...
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How many mappings you have done in your project(in a banking)?
jayapraveen
- Oct 12th, 2010
In a banking project if we are dealing with a Customer information ModuleThen we require4 dimensions7 Fact tablesminimum of 45 mappings requiredsize of Database is 9GB required
Whatever
- Mar 19th, 2007
Exactly 93.133
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Sorted Input option in Incremental Aggregation
Why should not we use sorted input option when using Incremental Aggregation?
jayapraveen
- Oct 4th, 2010
Because of the performance tunning, because here the duplication of the data is sorted in the bginining of the aggregation itself so index cache and data cache ?is reduced so the performance is good.
ahammed
- Jul 21st, 2010
When you are selecting sorted input the data will be sorted and at the same time last record key value will be stored in repository. After that days or months passing on some new records will be ...
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What is redo log file in Informatica?
jayapraveen
- Oct 4th, 2010
Redo log file keeps the value when the "commit"command executes and replaces the value with new value.
satoru
- Jun 30th, 2010
In the Oracle RDBMS environment, redo logs comprise files in a proprietary format which log a history of all changes made to the database. Before a user receives a "Commit complete" message,...
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How does Informatica get sources from IBM MQ Series
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Data Loading While Session Failed
If there are 10000 records and while loading, if the session fails in between, how will you load the remaining data?
reddykuruganti
- Jun 7th, 2010
Simply you can restart the session, by selecting truncate table option in the session properties.
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Source Qualifier
What is a Source Qualifier?
jayapraveen
- Oct 2nd, 2010
Source qualifier is nothing?but a filter and it is an active transformation, it is used to join the data coming from homogeneous database the best practice of the mapping is using expression before other transformation after the source qualifier.
Informatica Interview Questions
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