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hkice
Advocate II
Advocate II

Changing Data Type of a Column

My data source is a SharePoint list. When I change the data type of one of the column I get the following pop-up message box:

 

"With this data type change, your data will be stored differently. This may cause a loss of data or precision. After you make this change, you can restore the column by refreshing the table."

 

I understand that if I try to change a data type of TEXT to NUMBER, I can lose data or precision.   But what does the second half of the statement mean - "...., you can restore the column by refreshing the table" - what is "refreshing the table" mean ?

 

These are the steps I did:

1.  I changed a column from TEXT to NUMBER,

2.  Saved the changes, and

3.  then REFRESHED the data.

 

The data type of the Column that was changed is still of data type  NUMBER ? Nothing was "restored" that I can see.  What am I missing ?

 

Thank you.

1 ACCEPTED SOLUTION

Hi @hkice,

It seems like you still confused about how to use the refresh feature to restore the table records, right?

If this is a case, it should be related to power bi data structure. The change data type operation will be applied a 'change data type' step to the backend query table then power bi will force update the data model table fields to sync the records structures.

This operation has not affected the raw data structure which cache in previous query table steps.
If you change back the data type and do refresh operations, power bi will re-generate the data model tables based on the backend query table structure and these data type meditation will be restored. ('restore the column by refreshing the table' mean the use refresh feature to re-generate the data model table with raw table structure)

Hope the above description can help you to know more about these.

Regards,
Xiaoxin Sheng

Community Support Team _ Xiaoxin
If this post helps, please consider accept as solution to help other members find it more quickly.

View solution in original post

3 REPLIES 3
v-shex-msft
Community Support
Community Support

Hi @hkice,

In fact, the backend query tables are stored based on query steps. (it does not contain any writeback feature)
It saved and logged each operation steps that you applied to it.  So you can review the raw data and type at the step before you apply the 'change data type' steps.

For the notice message, it probably means you can remove the 'change data type' steps and refresh to get the last record to power bi side to restore the data precision.

Regards,

Xiaoxin Sheng

Community Support Team _ Xiaoxin
If this post helps, please consider accept as solution to help other members find it more quickly.

I understand that Power BI records the steps and that I can retrace my steps ... but I still done get what the message is trying to tell me -  "With this data type change, your data will be stored differently. This may cause a loss of data or precision. After you make this change, you can restore the column by refreshing the table."

 

Thank you.

Hi @hkice,

It seems like you still confused about how to use the refresh feature to restore the table records, right?

If this is a case, it should be related to power bi data structure. The change data type operation will be applied a 'change data type' step to the backend query table then power bi will force update the data model table fields to sync the records structures.

This operation has not affected the raw data structure which cache in previous query table steps.
If you change back the data type and do refresh operations, power bi will re-generate the data model tables based on the backend query table structure and these data type meditation will be restored. ('restore the column by refreshing the table' mean the use refresh feature to re-generate the data model table with raw table structure)

Hope the above description can help you to know more about these.

Regards,
Xiaoxin Sheng

Community Support Team _ Xiaoxin
If this post helps, please consider accept as solution to help other members find it more quickly.

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