ypinky

 Profile Answers by ypinky Questions by ypinky

• Jul 26th, 2010

SCD-1 (Current)Overwriting the old values in the dimension record. SCD-2 (History and Current)Creating an additional dimension record at the time of the change with the new attribute values. ...

desaial

 Profile Answers by desaial Questions by desaial

• Dec 9th, 2008

SCD means Slowly Changing Dimension. The price of the product, address of the person, name of the city are few examples of SCD.There are three methods to capture SCD.Type 1: Overwriting the old values...

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Is time a semi-additive fact or a non-additive fact?Explain it with an example.

yuvaevergreen

 Profile Answers by yuvaevergreen Questions by yuvaevergreen

• Sep 7th, 2010

Time is a semi additive measure.  If you have a fact table containing information on the number of items in stock in a warehouse, then it would never make sense to aggregate these measures over t...

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Is there any option other than Surrogate key or concatenated key?

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ravikiranrali  

 Profile Answers by ravikiranrali Questions by ravikiranrali

• Member Since May-2008 | May 9th, 2009

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Two main reasons to generate and maintain a surrogate key on DW side:

1. If your DW has multiple sources for a dimension or fact, the PK ID fields can have same values from different sources. The only way you can handle this is by maintaining the composite primary key on these columns. Now lets imagine that you have some 10 dimensions in a subject area, you would expect to have only 10 keys in the Fact, but by having the composite keys you would endup creating 20 or more keys on the fact. This would inturn adversely affect your query performance.

2. Another case, suppose some data migration activities take place on the source side -- which is quite possible if the source system platform is changed or your company acquiered another company and integrating the data etc -- if the source side architect decides to change the PK field value itself of a table in source, then your DW would see this as a new record and insert it and this would result in data inconsistency /discrepency between the source and DW and it could be a nightmare to fix the issue. By having a separate surrogate key on DW side that is generated based on the grain of the source table (not on the IDs), you are immune to any such PK value changes on the source side.

mundravijay

 Profile Answers by mundravijay Questions by mundravijay

• Jan 21st, 2011

In fact table because of we are using summerized data, we will be including all dimensional's table's primrary key as a Foreign key for their relationship.The key should me in the Lowest Level...

ravikiranrali

 Profile Answers by ravikiranrali Questions by ravikiranrali

• May 9th, 2009

Two main reasons to generate and maintain a surrogate key on DW side:1. If your DW has multiple sources for a dimension or fact, the PK ID fields can have same values from different sources. The only ...

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dave

• Aug 6th, 2011

ODS is a datastore that contains wide breath of data but not very deep(aggregated not atomic levels), OLTP is used to describe the transaction profile that will access the ODS, small predictable trans...

njvijay

 Profile Answers by njvijay Questions by njvijay

• May 12th, 2008

1. ODS  - It is a decision support system which contains snapshot of current data for day to day analysis. This may include little history data also   OLTP - It is a trasaction system t...

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Sreedhar Lokaray

• Nov 3rd, 2011

Let me just give the Data quality problems. If I explain it will go page by page. 1. Dummy values in source system fields. 2. Absence of data in source system fields. 3. Multipurpose fields. 4. Crypt...

Faizal

• Aug 30th, 2011

You have to test all the transformations in your ETL and write negative scenarios.

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satwant singh

• Nov 29th, 2011

Full Load is the entire data dump load taking place the very first time. Gradually to synchronize the target data with source data, there are further 2 techniques:- Refresh load - Where the existing...

Sreedhar Lokaray

• Nov 3rd, 2011

In simple words, after transforming the data it is loaded into the DWH. Two distinct groups of tasks form the data loading function. When you complete the design and construction of the DWH and go liv...

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uga_boy

• Jan 20th, 2012

Surrogate keys are advisable for a few different reasons: 1. In a large enterprise environment with many data sources to pull from you will inevitably come across a data feed that either does not con...

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Sandhya.Kishan

 Profile Answers by Sandhya.Kishan Questions by Sandhya.Kishan

• Jul 10th, 2012

May be Applet.getImage(new URL(...)) can be used to convert java applet into image file.

munavar.shaik

 Profile Answers by munavar.shaik Questions by munavar.shaik

• Jan 18th, 2011

Java applets are not used in DWH. So its irrelevant question in DWH concepts group.

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Sandhya.Kishan

 Profile Answers by Sandhya.Kishan Questions by Sandhya.Kishan

• Jul 10th, 2012

The shortcut keys are related to a specific window and will only work in that window. It is part of the name of a menu item or button, where it can be underlined, and is available (without modifiers) ...

elanchum

• Jul 18th, 2011

Hotkey: which is used to open r close an application.....
shortcutkey: used to perform actions with in the application....

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Which table is large terms of size, fact table or dimension table? Explain

goeljessica

 Profile Answers by goeljessica Questions by goeljessica

• Sep 7th, 2012

Fact tables: Have any measurable value in it and it contain foreign key of all the dimension table.

Dimension Tables: Do not have any numeric value, and it shows the characteristics that describe a transaction.

santhosh

• May 28th, 2012

Dimension:It gives description about fact.

Fact:Is knows as Key Identifier(Measures)

EX:
Empno Empname Sal Deptno
1 A 20,000 201
2 B 15,000 203

All facts are numeric

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My target table has loaded with 10000 records from source table.
Now, I want to verify the target table whether it has been loaded with correct data or it has any junk values

How do I test the above scenario.
As we can conclude that we cant check each and every record because of huge quantity.

Anu Sharma

• Apr 25th, 2016

First check the count of source and target
Then select first table minus second table and then we come to know if there is no record coming then values are loaded properly and if there are records appearing after executing the minus query then the records are not uploaded in the target table.

surendra

• Jul 9th, 2014

HI...
Write the Source query according the Business Logic ,write the target query for the same,export the two queries i.e is source and target to excel and with the help of open source tool db solo are beyond compare tool you can compare field to field and same the count too.

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cognos_anu

• Jun 20th, 2017

Fact less fact table contains only foreign keys/ids.
They don't contain measures/fact, numeric data.
They are used to capture the events.
for e.g. to capture attendance records

Sandipana

• Jan 20th, 2015

A factless fact table is fact table that does not contain fact. They contain only dimensional keys and it captures events that happen only at information level but not included in the calculations lev...

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Answered by: Praveen

• Aug 15th, 2005

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# Additive: Additive facts are facts that can be summed up through all of the dimensions in the fact table. 
# Semi-Additive: Semi-additive facts are facts that can be summed up for some of the dimensions in the fact table, but not the others. 
# Non-Additive: Non-additive facts are facts that cannot be summed up for any of the dimensions present in the fact table.

cognos_anu

• Jun 20th, 2017

The facts which cannot be summed up across any dimension.
for e.g. Percentage, temperature

Srikant

• Nov 20th, 2016

Please give me a fact table where I cannot add the percentage. Especially if the percentage is calculated for that particular fact table. Are we saying that percentages stored in the fact table might ...

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areeba

• Jan 31st, 2018

DWH is an application where we get or fetch the data while BI is a field where we use data for the Business purpose.

Dashmesh Singh

• Dec 26th, 2014

Please check this best tabular difference
https://www.youtube.com/watch?v=oSSYl9509JM

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sivaranjith

• Mar 25th, 2019

Surrogate key is used in Datawarehousing concept for SCD-2 implementation and there are history records stored for a particular record we cant use primary key as integrity violation will occur for the same record so in that case Surrogate key is used for historical and new records.

Sreedhar Lokaray

• Nov 2nd, 2011

By definition, surrogate key is a system generated key. This key is used as Primary key in the Dimensions. Why? There are generally two principles to be applied when choosing Primary keys for the Dim...

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