SSAS Tabular Add Column via TMSL - ssas-tabular

Question

Good Morning,
Objective: I am working on trying to add new columns to a SSAS Tabular Model table. With a long-term aim to programmaticly made large-batch changes when needed.
Resources I've found:
https://learn.microsoft.com/en-us/sql/analysis-services/tabular-models-scripting-language-commands/create-command-tmsl
This one gives the template I've been following but seems to not work.
What I have tried so far:
{
"create": {
"parentObject": {
"database": "TabularModel_1_dev"
, "table": "TableABC"
},
"columns": [
{
"name": "New Column"
, "dataType": "string"
, "sourceColumn": "Column from SQL Source"
}
]
}
}
This first one is the most true to the example but returns the following error:
"The JSON DDL request failed with the following error: Unrecognized JSON property: columns. Check path 'create.columns', line 7, position 15.."
Attempt Two:
{
"create": {
"parentObject": {
"database": "TabularModel_1_dev"
, "table": "TableABC"
},
"table": {
"name": "Item Details by Branch",
"columns": [
{
"name": "New Column"
, "dataType": "string"
, "sourceColumn": "New Column"
}
]
}
}
}
Adding table within the child list returns error too;
"...Cannot execute the Create command: the specified parent object cannot have a child object of type Table.."
Omitting the table within the parentObject is unsuccessful as well.

Answer 1

I know it's been three years since the post, but I too was attempting the same thing and stumbled across this post in my quest. I ended up reaching out to microsoft and was told that the Add Column example they gave in their documentation was a "doc bug". In fact, you can't add just a column, you have to feed it an entire table definition via createOrReplace.
SSAS Error Creating Column with TMSL