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explain in detail about
type 1,
type 2(SCD),
type 3 ?

  
Total Answers and Comments: 6 Last Update: January 29, 2007     Asked by: prasath 
  
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October 04, 2005 10:26:18   #1  
Sithu        

RE: explain in detail about type 1, typ...

Type-1

Most Recent Value

Type-2(full History)

i) Version Number

ii) Flag

iii) Date

Type-3

Current and one Perivies value


 
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October 07, 2005 03:10:22   #2  
sai        

RE: explain in detail about type 1, typ...
fine
 
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October 18, 2005 08:07:02   #3  
Henry        

RE: explain in detail about type 1, typ...

SCD

Type 1 : overwrite data is to be there.

Type 2 : current, recent and history data should be there.

Type 3: current and recent data should be there.


 
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October 21, 2005 03:11:17   #4  
sranjanim        

RE: explain in detail about type 1, typ...
Henry Wrote:

SCD

Type 1 : overwrite data is to be there.

Type 2 : current, recent and history data should be there.

Type 3: current and recent data should be there.



 
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March 14, 2006 06:20:58   #5  
ravi kumar guturi        

RE: explain in detail about type 1, typ...

SCD means If the data in the dimension is happen to change very rarely,

Mainly SCD 3 types

1)SCD-1:HERE THE PREVIOUS DATA OVERWRITE BY CURRENT DATA

MEANS HERE ONLY MAINTAIN CURRENT DATA.

2)SCD-2: HERE JUST ADD THE ADDITIONAL RECORDS

IN SCD2 3 TYPES1)VERSIONING2)FLAGVALUE3)EFFECT DATE RANGE

VERSIONING: MEANS HERE JUST SEND THE UPDATED RECORDS TO THE TARGET ALONG WITH VERSION NUMBER.

NEW RECORDS WILL BE SENDING TO THE TARGET ALONG WITH PRIMARY KEY

FLAGVALUE:HERE UPDATED RECORDS SEND TO THE TARGET ALONG WITH 0

AND RECENT RECORDS SEND TO THE TARGET ALONG WITH 1

EFFECTIVE DATE RANGE:MEANS HERE TRACKS THE BOTH PREVIOUS AND CURRENT DATA

3)SCD-3: HERE MAINTAINS JUST PREVIOUS AND CURRENT DATA.


 
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January 29, 2007 05:20:03   #6  
Arvind Kumar        

RE: explain in detail about type 1, typ...
Type1: Rows containing changes to existing dimensions are updated in the target by overwriting the existing dimension. In the Type 1 Dimension mapping, all rows contain current dimension data. Use the Type 1 Dimension mapping to update a slowly changing dimension table when you do not need to keep any previous versions of dimensions in the table. Type 2: The Type 2 Dimension Data mapping inserts both new and changed dimensions into the target. Changes are tracked in the target table by versioning the primary key and creating a version number for each dimension in the table. Use the Type 2 Dimension/Version Data mapping to update a slowly changing dimension table when you want to keep a full history of dimension data in the table. Version numbers and versioned primary keys track the order of changes to each dimension. Type 3: The Type 3 Dimension mapping filters source rows based on user-defined comparisons and inserts only those found to be new dimensions to the target. Rows containing changes to existing dimensions are updated in the target.
 
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