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3. Configure the <SYSTEM Delta> Parameter

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The <SYSTEM Delta> Parameter controls how existing records in your Fact Table are replaced when a new WRITE process is executed in the Web Client.

The most important

Named ranges in this section (overview):

  • data1_CELLS01_SysDELTA

Rules:

  • If a WRITE process is executed then the <SYSTEM Delta> Parameter from the current sheet is detected.
  • ALL already existing records in the Fact Table with this <SYSTEM Delta> Parameter are deleted.
  • It does not matter if the number of new records meets the number of records that are deleted. So,1000 existing records can be replaced by 1 new record.
  • As long the <SYSTEM Delta> Parameter ist not explicitly defined, the current element from the dimension tree is used as <SYSTEM Delta> Parameter. This definition is right if you do not intend to gather historical data in your application.

Recommendations:

  • The <SYSTEM Delta> Parameter should be defined actively in order to keep and gather historical data in your application.
  • We strongly recommend to use the dimension key (Parameter "data1_CELLS01_DIMxxx_Key") instead of the dimension name since the dimension name could have duplicates.
  • In Multi-Sheet Templates we recommend to set a sheet-specific <SYSTEM Delta> Parameter.

1. Default Behaviour

As long the SYSTEM Delta Parameter ist not explicitly defined, the current element from the dimension tree is used as SYSTEM Delta Paramter.

Look at this example: enter your data in the spreadsheet and pressing the WRITE button ...

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... generates 7 records in your fact table:

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The 7 records got the entry from the Dim01 KEY (= dimension tree) also as SYSTEM Delta entry:

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If you change now the data in the spreadsheet and WRITE those new data into your application ...

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... the 3 new records will replace the 7 prior records:

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This definition is right if you do not intend to gather historical data in your application.

2. Actively define the SYSTEM Delta Parameter

We strongly recommend to actively define the SYSTEM Delta Parameter by adding a named range "data1_CELLS01_SysDELTA" to your spreadsheet. Please remember that all named ranges in data1.io spreadsheets must be defined on a sheet (and not workbook) level.

Entering data and pressing the WRITE button ...

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... again generates 7 records in your Fact Table. But this time the SYSTEM Delta field is filled with an element AND date specific text string:

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Changing the current week in the spreadsheet generates a new SYSTEM Delta text string. Entering data and pressing the WRITE button ...

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... generates 3 new records (for the new week) WITHOUT replacing the existing records from last week:

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3. Use the dimension key instead of the dimension name

We strongly recommend to use the dimension key (Parameter "data1_CELLS01_DIMxxx_Key") instead of the dimension name since the dimension name could have duplicates.

4. Configure the SYSTEM Delta Parameter in Multi-Sheet Templates

In Multi-Sheet Templates we recommend to set a sheet-specific <SYSTEM Delta> Parameter since it is more intuitive. If you decide to use the same <SYSTEM Delta> Parameter in all or in several sheets then the delete process will be executed only once per <SYSTEM Delta> Parameter (and not per sheet).

 

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