How can I make bulkCopy map the same columns? - sql-server

Question

Suppose I have a SQL Table that has these columns:
[server_name],[SESSION_ID],[SESSION_SPID]
I am trying to copy values stored in a data table ($dmvResult) to the SQL Table above ($Table)
$dmvResult = DMV_Query 'SELECT [SESSION_ID]
,[SESSION_SPID]
FROM $SYSTEM.DISCOVER_SESSIONS';
$ConnectionString ='Data Source=$server; Database=$database; Trusted_Connection=True;'
$bulkCopy = new-object Data.SqlClient.SqlBulkCopy($ConnectionString)
$bulkCopy.DestinationTableName=$Table
$bulkCopy.WriteToServer($dmvResult)
While the copying is being done successfully, there is an issue: it's copying by position, not by column name match. In other words, the copied columns are not being mapped and copied to the same columns.
[SESSION_ID] is being copied to [server_name] and
[SESSION_SPID] is being copied to [SESSION_ID]
How can I tell bulkCopy to match columns and copy?
The result copy should be [server_name] being empty because it wasn't selected from DMV query.
I found a neat solution in this thread:
https://stackoverflow.com/a/20045505/8397835
but I dont know how to translate it to my powershell code:
var meta = definition.Context.Mapping.GetMetaType(typeof(T));
foreach (var col in meta.DataMembers)
{
copy.ColumnMappings.Add(col.Member.Name, col.MappedName);
}
EDIT: foreach column.ColumnName output
EDIT2:
i tried this:
$dmvResult.Columns |%{$_.Name}
and it doesnt output anything.
before you say $dmvResult data table must be empty then, explain how is it possible that this actually works and copies in data?
$bulkCopy.ColumnMappings.Add('SESSION_ID', 'SESSION_ID')
$bulkCopy.ColumnMappings.Add('SESSION_SPID', 'SESSION_SPID')
$bulkCopy.WriteToServer($dmvResult)
and for some reason, its outputting this to the console as well:
so the data table $dmvResult is clearly populated.
i was hoping instead of defining mapping for every single column like this:
$bulkCopy.ColumnMappings.Add('SESSION_SPID', 'SESSION_SPID')
instead there would be anutomatic option like this:
foreach ($column in $dmvResult.Columns) { $bulkCopy.ColumnMappings.Add($column.ColumnName, $column.ColumnName)}
but that throws exception:
Exception calling "WriteToServer" with "1" argument(s): "The given
ColumnMapping does not match up with any column in the source or
destination."

Answer 1

A very weird solution but I just had to add a comma here before $dataset:
,$dataSet.Tables[0]
in the DMV_Query function
and then i used this foreach loop
foreach ($column in $dmvResult.Columns) { $bulkCopy.ColumnMappings.Add($column.ColumnName, $column.ColumnName) > $null }
and it worked!
it now maps the columns automatically!!