SqlBulkCopy fails with InvalidOperationException when target table has computed columns

[priyankatiwari08]

Describe the bug

When using SqlBulkCopy to insert rows into a table that has a computed column, the operation fails with InvalidOperationException: The given ColumnMapping does not match up with any column in the source or destination even though all non-computed columns are correctly mapped.

To reproduce

// Target table:
// CREATE TABLE Orders (
//   Id INT IDENTITY PRIMARY KEY,
//   Quantity INT,
//   UnitPrice DECIMAL(10,2),
//   TotalPrice AS (Quantity * UnitPrice) PERSISTED
// )

using var bulkCopy = new SqlBulkCopy(connection);
bulkCopy.DestinationTableName = "Orders";
bulkCopy.ColumnMappings.Add("Quantity", "Quantity");
bulkCopy.ColumnMappings.Add("UnitPrice", "UnitPrice");

var dt = new DataTable();
dt.Columns.Add("Quantity", typeof(int));
dt.Columns.Add("UnitPrice", typeof(decimal));
dt.Rows.Add(5, 19.99m);

await bulkCopy.WriteToServerAsync(dt); // throws InvalidOperationException

Expected behavior

SqlBulkCopy should skip computed columns automatically when explicit column mappings are provided for the non-computed columns only.

Actual behavior

System.InvalidOperationException: The given ColumnMapping does not match up with any column in the source or destination.
   at Microsoft.Data.SqlClient.SqlBulkCopy.WriteToServerAsync(...)

Further technical details

Microsoft.Data.SqlClient version: 6.0.0
Target framework: .NET 8.0
SQL Server version: SQL Server 2022 (16.0.4135)
Operating system: Windows Server 2022

[github-actions]

🔍 Triage Summary

Check	Result
Issue type	Bug
Environment	All required environment details provided for investigation
Area	Area\Sql Bulk Copy
Duplicates	None found
Regression	Not indicated

Analysis

This bug affects SqlBulkCopy when the destination table contains computed/persisted columns (e.g., TotalPrice AS (Quantity * UnitPrice) PERSISTED). Even when explicit column mappings are provided that correctly map only the writable non-computed columns, the operation throws InvalidOperationException with a misleading error about mismatched column mappings. The likely root cause is in the column mapping validation logic within SqlBulkCopy (specifically in WriteToServerInternalRestAsync / AnalyzeTargetAndCreateUpdateBulkCommand) which does not skip computed columns during mapping resolution. This is a P2 bug — it blocks a valid and common table design pattern, but there is a known workaround (not mapping those columns at all and ensuring the table allows null inserts, though that doesn't apply to persisted computed columns).

Next Steps

• Assign to Copilot coding agent to investigate the SqlBulkCopy column mapping validation logic, specifically how destination column metadata is retrieved (likely via SET FMTONLY or sp_tablecollations/sp_describe_first_result_set) and how computed columns are identified and excluded from validation. The fix should ensure that when explicit column mappings are provided, computed destination columns that are not included in the mappings are silently skipped rather than raising an error.

Generated by SqlClient Issue Auto-Triage for issue #20 · ● 440.6K · ◷