feat(datasync): extend DbBulkMergeDestination with excludeFromUpdate and updateCondition

NEW/src/JdeScoping.DataSync/Etl/Destinations/DbBulkMergeDestination.cs

@@ -24,6 +24,8 @@ public class DbBulkMergeDestination : IImportDestination
     private readonly string _tableName;
     private readonly string[] _matchColumns;
     private readonly string[]? _updateColumns;
+    private readonly string[]? _excludeFromUpdate;
+    private readonly string? _updateCondition;
     private readonly int _batchSize;
     private readonly int _commandTimeoutSeconds;
 
@@ -37,6 +39,8 @@ public class DbBulkMergeDestination : IImportDestination
     /// <param name="tableName">Name of the destination table.</param>
     /// <param name="matchColumns">Columns to match on for determining existing rows (key columns).</param>
     /// <param name="updateColumns">Columns to update when a row matches. If null, all non-match columns are updated.</param>
+    /// <param name="excludeFromUpdate">Columns to exclude from the UPDATE clause. Takes precedence over updateColumns.</param>
+    /// <param name="updateCondition">Optional SQL condition to add to the WHEN MATCHED clause (e.g., "source.LastUpdate > target.LastUpdate").</param>
     /// <param name="batchSize">Number of rows per batch. 0 uses the default (10000).</param>
     /// <param name="commandTimeoutSeconds">Command timeout in seconds. 0 uses the default (600).</param>
     public DbBulkMergeDestination(
@@ -44,6 +48,8 @@ public class DbBulkMergeDestination : IImportDestination
         string tableName,
         string[] matchColumns,
         string[]? updateColumns = null,
+        string[]? excludeFromUpdate = null,
+        string? updateCondition = null,
         int batchSize = 0,
         int commandTimeoutSeconds = 0)
     {
@@ -57,6 +63,8 @@ public class DbBulkMergeDestination : IImportDestination
         _tableName = tableName;
         _matchColumns = matchColumns;
         _updateColumns = updateColumns;
+        _excludeFromUpdate = excludeFromUpdate;
+        _updateCondition = updateCondition;
         _batchSize = batchSize > 0 ? batchSize : DefaultBatchSize;
         _commandTimeoutSeconds = commandTimeoutSeconds > 0 ? commandTimeoutSeconds : DefaultCommandTimeoutSeconds;
     }
@@ -101,8 +109,12 @@ public class DbBulkMergeDestination : IImportDestination
 
             // Determine update columns (all non-match columns if not specified), filtered to destColumns
             var matchSet = new HashSet<string>(_matchColumns, StringComparer.OrdinalIgnoreCase);
+            var excludeSet = _excludeFromUpdate != null
+                ? new HashSet<string>(_excludeFromUpdate, StringComparer.OrdinalIgnoreCase)
+                : new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+
             var updateCols = (_updateColumns ?? allColumns.Where(c => !matchSet.Contains(c)).ToArray())
-                .Where(c => destColumns.Contains(c))
+                .Where(c => destColumns.Contains(c) && !excludeSet.Contains(c))
                 .ToArray();
 
             // Build MERGE SQL
@@ -221,7 +233,14 @@ public class DbBulkMergeDestination : IImportDestination
 
         if (updateColumns.Count > 0)
         {
-            sb.AppendLine("WHEN MATCHED THEN UPDATE SET");
+            if (!string.IsNullOrWhiteSpace(_updateCondition))
+            {
+                sb.AppendLine($"WHEN MATCHED AND {_updateCondition} THEN UPDATE SET");
+            }
+            else
+            {
+                sb.AppendLine("WHEN MATCHED THEN UPDATE SET");
+            }
             sb.AppendLine(string.Join(", ", updateColumns.Select(c => $"target.[{c}] = source.[{c}]")));
         }