Fix Oracle MERGE ORA-02012 error - invalid syntax

src/PhenX.EntityFrameworkCore.BulkInsert.Oracle/OracleBulkInsertProvider.cs

@@ -59,7 +59,7 @@ protected override Task BulkInsert<T>(
 
         using var bulkCopy = new OracleBulkCopy(connection, options.CopyOptions);
 
-        bulkCopy.DestinationTableName = tableInfo.QuotedTableName;
+        bulkCopy.DestinationTableName = tableName;
         bulkCopy.BatchSize = options.BatchSize;
         bulkCopy.BulkCopyTimeout = options.GetCopyTimeoutInSeconds();
 

src/PhenX.EntityFrameworkCore.BulkInsert.Oracle/OracleDialectBuilder.cs

@@ -35,41 +35,54 @@ public override string BuildMoveDataSql<T>(
         // Merge handling
         if (onConflict is OnConflictOptions<T> onConflictTyped)
         {
-            IEnumerable<string> matchColumns;
+            // Oracle MERGE doesn't support returning entities
+            if (returnedColumns.Count != 0)
+            {
+                throw new NotSupportedException("Oracle MERGE does not support returning entities. Use ExecuteBulkInsertAsync without returning results when using conflict resolution.");
+            }
+
+            IReadOnlyList<string> matchColumns;
             if (onConflictTyped.Match != null)
             {
-                matchColumns = GetColumns(target, onConflictTyped.Match);
+                matchColumns = GetColumns(target, onConflictTyped.Match).ToList();
             }
             else if (target.PrimaryKey.Length > 0)
             {
-                matchColumns = target.PrimaryKey.Select(x => x.QuotedColumName);
+                matchColumns = target.PrimaryKey.Select(x => x.QuotedColumName).ToList();
             }
             else
             {
                 throw new InvalidOperationException("Table has no primary key that can be used for conflict detection.");
             }
 
-            q.AppendLine($"MERGE INTO {target.QuotedTableName} AS {PseudoTableInserted}");
+            // Validate that all match columns are available in the source subquery
+            var insertedColumnNames = insertedColumns.Select(c => c.QuotedColumName).ToHashSet();
+            var missingMatchColumns = matchColumns.Where(c => !insertedColumnNames.Contains(c)).ToList();
+            if (missingMatchColumns.Count != 0)
+            {
+                throw new InvalidOperationException(
+                    $"Oracle MERGE requires match columns to be present in the source data. " +
+                    $"The following match columns are not available: {string.Join(", ", missingMatchColumns)}. " +
+                    $"This can happen when using auto-generated primary key columns for conflict detection. " +
+                    $"Use the 'Match' option to specify non-generated columns for conflict detection, " +
+                    $"or set 'CopyGeneratedColumns = true' if the generated column values are provided.");
+            }
+
+            // Oracle MERGE syntax does NOT use AS for table aliases
+            q.AppendLine($"MERGE INTO {target.QuotedTableName} {PseudoTableInserted}");
 
             q.Append("USING (SELECT ");
             q.AppendColumns(insertedColumns);
-            q.Append($" FROM {source}) AS {PseudoTableExcluded} (");
-            q.AppendColumns(insertedColumns);
-            q.AppendLine(")");
-
-            q.Append("ON ");
-            q.AppendJoin(" AND ", matchColumns, (b, col) => b.Append($"{PseudoTableInserted}.{col} = {PseudoTableExcluded}.{col}"));
+            // Oracle MERGE syntax does NOT use AS for subquery aliases
+            q.Append($" FROM {source}) {PseudoTableExcluded}");
             q.AppendLine();
 
-            if (onConflictTyped.Update != null)
-            {
-                var columns = target.GetColumns(false);
-
-                q.AppendLine("WHEN MATCHED THEN UPDATE SET ");
-                q.AppendJoin(", ", GetUpdates(context, target, columns, onConflictTyped.Update));
-                q.AppendLine();
-            }
+            // Oracle requires ON clause conditions to be wrapped in parentheses
+            q.Append("ON (");
+            q.AppendJoin(" AND ", matchColumns, (b, col) => b.Append($"{PseudoTableInserted}.{col} = {PseudoTableExcluded}.{col}"));
+            q.AppendLine(")");
 
+            // Oracle MERGE syntax: WHEN NOT MATCHED clause for inserts, followed by WHEN MATCHED clause for updates
             q.Append("WHEN NOT MATCHED THEN INSERT (");
             q.AppendColumns(insertedColumns);
             q.AppendLine(")");
@@ -78,10 +91,33 @@ public override string BuildMoveDataSql<T>(
             q.AppendJoin(", ", insertedColumns, (b, col) => b.Append($"{PseudoTableExcluded}.{col.QuotedColumName}"));
             q.AppendLine(")");
 
-            if (returnedColumns.Count != 0)
+            if (onConflictTyped.Update != null)
             {
-                q.Append("OUTPUT ");
-                q.AppendJoin(", ", returnedColumns, (b, col) => b.Append($"{PseudoTableInserted}.{col.QuotedColumName} AS {col.QuotedColumName}"));
+                q.Append("WHEN MATCHED ");
+
+                if (onConflictTyped.RawWhere != null || onConflictTyped.Where != null)
+                {
+                    if (onConflictTyped is { RawWhere: not null, Where: not null })
+                    {
+                        throw new ArgumentException("Cannot specify both RawWhere and Where in OnConflictOptions.");
+                    }
+
+                    q.Append("AND ");
+                    AppendConflictCondition(q, target, context, onConflictTyped);
+                }
+
+                q.AppendLine("THEN UPDATE SET ");
+                // Oracle MERGE: columns in ON clause cannot be updated, so exclude match columns
+                // Use insertedColumns instead of all columns because the USING subquery only contains insertedColumns
+                var matchColumnSet = matchColumns.ToHashSet();
+                var updateableColumns = insertedColumns.Where(c => !matchColumnSet.Contains(c.QuotedColumName)).ToList();
+                if (updateableColumns.Count == 0)
+                {
+                    throw new InvalidOperationException(
+                        "Oracle MERGE cannot update any columns because all available columns are used in the ON clause for conflict detection. " +
+                        "Specify different columns in the 'Match' option or use specific columns in the 'Update' expression.");
+                }
+                q.AppendJoin(", ", GetUpdates(context, target, updateableColumns, onConflictTyped.Update));
                 q.AppendLine();
             }
         }

tests/PhenX.EntityFrameworkCore.BulkInsert.Tests/Tests/Merge/MergeTestsBase.cs

@@ -33,6 +33,8 @@ public async Task InsertEntities_MultipleTimes(InsertStrategy strategy)
     {
         Skip.If(_context.IsProvider(ProviderType.PostgreSql));
         Skip.If(_context.IsProvider(ProviderType.SqlServer));
+        // Oracle MERGE requires match columns to be in the source data; auto-generated Id is not available
+        Skip.If(_context.IsProvider(ProviderType.Oracle));
 
         // Arrange
         var entities = new List<TestEntity>
@@ -126,6 +128,8 @@ public async Task InsertEntities_MultipleTimes_With_Conflict_On_Id(InsertStrateg
     public async Task InsertEntities_WithConflict_SingleColumn(InsertStrategy strategy)
     {
         Skip.If(_context.IsProvider(ProviderType.MySql));
+        // Oracle MERGE does not support returning entities
+        Skip.If(_context.IsProvider(ProviderType.Oracle));
 
         // Arrange
         _context.TestEntities.Add(new TestEntity { TestRun = _run,Name = $"{_run}_Entity1" });
@@ -194,6 +198,8 @@ public async Task InsertEntities_WithConflict_DoNothing(InsertStrategy strategy)
     public async Task InsertEntities_WithConflict_RawCondition(InsertStrategy strategy)
     {
         Skip.If(_context.IsProvider(ProviderType.MySql));
+        // Oracle MERGE does not support returning entities
+        Skip.If(_context.IsProvider(ProviderType.Oracle));
 
         // Arrange
         _context.TestEntities.Add(new TestEntity { TestRun = _run, Name = $"{_run}_Entity1", Price = 10 });
@@ -237,6 +243,8 @@ public async Task InsertEntities_WithConflict_RawCondition(InsertStrategy strate
     public async Task InsertEntities_WithConflict_ExpressionCondition(InsertStrategy strategy)
     {
         Skip.If(_context.IsProvider(ProviderType.MySql));
+        // Oracle MERGE does not support returning entities
+        Skip.If(_context.IsProvider(ProviderType.Oracle));
 
         // Arrange
         _context.TestEntities.Add(new TestEntity { TestRun = _run, Name = $"{_run}_Entity1", Price = 10 });
@@ -280,6 +288,8 @@ public async Task InsertEntities_WithConflict_ExpressionCondition(InsertStrategy
     public async Task InsertEntities_WithConflict_ComplexExpressionCondition(InsertStrategy strategy)
     {
         Skip.If(_context.IsProvider(ProviderType.MySql));
+        // Oracle MERGE does not support returning entities
+        Skip.If(_context.IsProvider(ProviderType.Oracle));
 
         // Arrange
         _context.TestEntities.Add(new TestEntity { TestRun = _run, Name = $"{_run}_Entity1", Price = 10 });
@@ -312,6 +322,8 @@ public async Task InsertEntities_WithConflict_ComplexExpressionCondition(InsertS
     public async Task InsertEntities_WithConflict_MultipleColumns(InsertStrategy strategy)
     {
         Skip.If(_context.IsProvider(ProviderType.MySql));
+        // Oracle MERGE does not support returning entities
+        Skip.If(_context.IsProvider(ProviderType.Oracle));
 
         // Arrange
         _context.TestEntities.Add(new TestEntity { TestRun = _run, Name = $"{_run}_Entity1", Price = 10 });

tests/PhenX.EntityFrameworkCore.BulkInsert.Tests/Tests/Merge/MergeTestsOracle.cs

@@ -0,0 +1,12 @@
+using PhenX.EntityFrameworkCore.BulkInsert.Tests.DbContainer;
+using PhenX.EntityFrameworkCore.BulkInsert.Tests.DbContext;
+
+using Xunit;
+
+namespace PhenX.EntityFrameworkCore.BulkInsert.Tests.Tests.Merge;
+
+[Trait("Category", "Oracle")]
+[Collection(TestDbContainerOracleCollection.Name)]
+public class MergeTestsOracle(TestDbContainerOracle dbContainer) : MergeTestsBase<TestDbContextOracle>(dbContainer)
+{
+}