Append nested list

Author: Giorgi

DuckDB.NET.Data/DuckDBAppenderRow.cs

@@ -104,7 +104,7 @@ public DuckDBAppenderRow AppendValue(TimeSpan? value)
 
     #region Composite Types
 
-    public DuckDBAppenderRow AppendValue<T>(IReadOnlyCollection<T>? value) => AppendCollectionValue(value);
+    public DuckDBAppenderRow AppendValue<T>(IReadOnlyCollection<T>? value) => AppendValueInternal(value);
 
     #endregion
 
@@ -119,17 +119,6 @@ private DuckDBAppenderRow AppendValueInternal<T>(T? value)
         return this;
     }
 
-    private DuckDBAppenderRow AppendCollectionValue<T>(IReadOnlyCollection<T>? value)
-    {
-        CheckColumnAccess();
-
-        vectorWriters[columnIndex].AppendCollection(value, rowIndex);
-
-        columnIndex++;
-
-        return this;
-    }
-
 #if NET6_0_OR_GREATER
     private unsafe DuckDBAppenderRow AppendSpan(Span<byte> val)
     {

DuckDB.NET.Data/DuckDBDataReader.cs

@@ -76,15 +76,18 @@ private bool InitChunkData()
 
             currentChunkRowCount = (ulong)NativeMethods.DataChunks.DuckDBDataChunkGetSize(currentChunk);
 
-            vectorReaders = new VectorDataReaderBase[fieldCount];
-
+            if (vectorReaders.Length != fieldCount)
+            {
+                vectorReaders = new VectorDataReaderBase[fieldCount];
+            }
+            
             for (int index = 0; index < fieldCount; index++)
             {
                 var vector = NativeMethods.DataChunks.DuckDBDataChunkGetVector(currentChunk, index);
 
                 using var logicalType = NativeMethods.Query.DuckDBColumnLogicalType(ref currentResult, index);
 
-                vectorReaders[index] = VectorDataReaderFactory.CreateReader(vector, logicalType,
+                vectorReaders[index] = VectorDataReaderFactory.CreateReader(vector, logicalType, vectorReaders[index]?.ColumnName ??
                                                                             NativeMethods.Query.DuckDBColumnName(ref currentResult, index).ToManagedString(false));
             }
 

DuckDB.NET.Data/Internal/Writer/ListVectorDataWriter.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections;
 using System.Collections.Generic;
 using DuckDB.NET.Native;
 
@@ -16,21 +17,19 @@ public ListVectorDataWriter(IntPtr vector, void* vectorData, DuckDBType columnTy
         listDataWriter = VectorDataWriterFactory.CreateWriter(childVector, childType);
     }
 
-    internal override bool AppendCollection<T>(IReadOnlyCollection<T>? value, int rowIndex)
+    internal override bool AppendCollection(IList value, int rowIndex)
     {
-        if (value == null)
-        {
-            AppendNull(rowIndex);
-            return true;
-        }
-
         var index = 0;
 
         foreach (var item in value)
         {
-            listDataWriter.AppendValue(item, index++);
+            listDataWriter.AppendValue(item, (int)offset + (index++));
         }
 
-        return AppendValueInternal(new DuckDBListEntry(offset, (ulong)value.Count), rowIndex);
+        var result = AppendValueInternal(new DuckDBListEntry(offset, (ulong)value.Count), rowIndex);
+
+        offset += (ulong)value.Count;
+
+        return result;
     }
 }

DuckDB.NET.Data/Internal/Writer/VectorDataWriterBase.cs

@@ -61,6 +61,7 @@ public unsafe void AppendValue<T>(T value, int rowIndex)
             TimeOnly val => AppendTimeOnly(val, rowIndex),
 #endif
             DateTimeOffset val => AppendDateTimeOffset(val, rowIndex),
+            IList val => AppendCollection(val, rowIndex),
             _ => ThrowException<T>()
         };
     }
@@ -95,7 +96,7 @@ public unsafe void AppendValue<T>(T value, int rowIndex)
 
     internal virtual bool AppendBigInteger(BigInteger value, int rowIndex) => ThrowException<BigInteger>();
 
-    internal virtual bool AppendCollection<T>(IReadOnlyCollection<T>? value, int rowIndex) => ThrowException<bool>();
+    internal virtual bool AppendCollection(IList value, int rowIndex) => ThrowException<bool>();
 
     private bool ThrowException<T>()
     {

DuckDB.NET.Test/ManagedAppenderTests.cs

@@ -272,19 +272,19 @@ public void TemporalValues()
     public void ListValues()
     {
         Command.CommandText = "CREATE TABLE managedAppenderLists(a INTEGER, b INTEGER[]" +
-                              //", c INTEGER[][]" +
+                              ", c INTEGER[][]" +
                               ");";
         Command.ExecuteNonQuery();
 
-        var rows = 20;
+        var rows = 2;
         using (var appender = Connection.CreateAppender("managedAppenderLists"))
         {
             for (int i = 0; i < rows; i++)
             {
                 appender.CreateRow()
                     .AppendValue(i)
-                    .AppendValue(Enumerable.Range(0, i).ToList())
-                    //.AppendValue(new List<List<int>>{ Enumerable.Range(0, 5).ToList() })
+                    .AppendValue(Enumerable.Range(0, 2).ToList())
+                    .AppendValue(new List<List<int>> { Enumerable.Range(0, 5).ToList(), Enumerable.Range(i + 2, 4).ToList() })
                     .EndRow();
             }
         }
@@ -296,7 +296,8 @@ public void ListValues()
         while (reader.Read())
         {
             var ints = reader.GetFieldValue<List<int>>(1);
-            ints.Should().BeEquivalentTo(Enumerable.Range(0, index++).ToList());
+            ints.Should().BeEquivalentTo(Enumerable.Range(0, 2).ToList());
+            var fieldValue = reader.GetFieldValue<List<List<int>>>(2);
         }
     }