How to remove and add keys? Table.ReplaceKeys how does it work?

[richard-powerbi]

I have a SQL table loaded in PBI. I want to create my own primary keys and qualify them as keys in PBI.

The documentation on Table.ReplaceKeys is really bad. Can anyone explain how it works? Or is there another way of doing this?

[dax · Accepted solution]

Hi @richard-powerbi , 

It seems to change key, you could try below M code and refer to power-query-m-primer-part13-tables-table-think-ii  and this post  for details.

let

   
  
  Source = #table(
    {"CompanyID", "Name", "Location"}, 
      {
        {1, "ABC Company", "Chicago"}, 
        {2, "ABC Company", "Charlotte"}, 
        {3, "Some Other Company", "Cincinnati"}
      }
    ),
  KeysTagged = Table.AddKey(Source, {"CompanyID"}, true),
  aa=Table.ReplaceKeys(
        KeysTagged,
        {
            [Columns = {"Location"},
            Primary = true]
        }
    )
in
 Table.Keys(aa)

Best Regards,
Zoe Zhi

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[richard-powerbi]

Another question, is below code correct if I want two columns to act as one composite key? Both columns do not have unique values, only the combination of them is unique.

= Table.ReplaceKeys(Source, {[Columns = List.Combine({{"Column1"}, {"Column2"}), Primary = true]})

Later on I will merge on these two columns and I would like this utilize this for performance. Does above code work for this?

@dax

[richard-powerbi]

Anyone knows?

[Smauro]

Hi @richard-powerbi,

You could simplify it as

... {[Columns = {"Column1", "Column2"}, Primary = true]})

and as long as it's unique you should see some performance improvements.