Decimal Type Join Columns in Modeling

[Anonymous]

Hi All,

In our project, we are using decimal(not fixed decimal) type Key columns for creating the relationship between dimensions and facts when we do modeling.

do we face any problems if we follow the above approach?

Thanks

Venkat

[TomMartens]

Hey,

I never heard of this before, I guess there will be some good reasoning for this kind of design decision.

Nevertheless, I guess as long as your decimal keys match the capabilities of the decimal (number) data type

https://docs.microsoft.com/en-us/sql/analysis-services/tabular-models/data-types-supported-ssas-tabu...

you are good to go.

Hopefully this is what you are looking for.

Regards,

Tom

[Anonymous]

The problem we are having in our case is, our key columns are drive keys, means it is a combinition of multiple columns, when we are derive these drive keys, their size is more than the normal whole number(bigint in sql server), to accomadate the same, we coverted all these drive key columns types to decimal number(not fixed decimal), which is equal to decimal(38,0) in sql server. We want to know the problems, we may face when we do like this.

[d_gosbell]

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@Anonymous wrote:

The problem we are having in our case is, our key columns are drive keys, means it is a combinition of multiple columns, when we are derive these drive keys, their size is more than the normal whole number(bigint in sql server), to accomadate the same, we coverted all these drive key columns types to decimal number(not fixed decimal), which is equal to decimal(38,0) in sql server. We want to know the problems, we may face when we do like this.

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I assume by drive keys you mean "derived" keys. If this is the case then using the decimal data type is a really bad idea. The decimal data type in tabular models is a floating point number, so it is not precise and this could cause two keys to possibly round differently and not match. Or worse still if could cause 2 different keys to round to the same value. You should use either a string or integer number for your keys.

[v-diye-msft]

Hi @Anonymous ,

If you'd like to know the limitation when using decimal type in power bi model, here're blogs for yourreference:

https://www.sqlbi.com/articles/understanding-numeric-data-type-conversions-in-dax/

https://www.qumio.com/Blog/Lists/Posts/Post.aspx?ID=50    

Best regards,

Dina Ye