Column created in a table appears in another table

Hi ChetanK004,

This behaviour is related to how Microsoft.AnalysisServices.Tabular manages object references in the Tabular Object Model (TOM). When you add a column to a table, the change is applied to the in-memory model, and then persisted when you call Model.SaveChanges(). If columns appear in another table, it usually indicates one of the following:

Please, look at steps bellow an try:

Root Causes

1. Shared or cloned references
   • If pbiColumns is referencing the same ColumnCollection object for both tables due to incorrect initialisation or reuse of objects, adding a column will affect both.
   • This can happen if the tables were cloned or created from the same object without deep copying.
2. Model refresh behaviour
   • After publishing, the service may apply schema changes during refresh, merging metadata from the original source and your custom changes.
   • If the original table and the custom table share the same Source or LineageTag logic, the refresh can propagate columns unexpectedly.
3. Intermittent timing
   • When changes are made immediately after publishing, the model may not have fully synchronised with the service, causing delayed appearance of columns.

Recommended Fixes

Ensure unique references

var pbiTable = database.Model.Tables
    .FirstOrDefault(x => x.Name.Equals(tableName, StringComparison.OrdinalIgnoreCase));

if (pbiTable == null)
    throw new Exception($"Table {tableName} not found.");

var pbiColumns = pbiTable.Columns;

database.Model.SaveChanges();