Add UseStreamingMode to DuckDBCommand

Author: Giorgi

DuckDB.NET.Data/DuckDBCommand.cs

@@ -24,6 +24,8 @@ public class DuckDBCommand : DbCommand
     public override bool DesignTimeVisible { get; set; }
     public override UpdateRowSource UpdatedRowSource { get; set; }
 
+    public bool UseStreamingMode { get; set; } = false;
+
     private string commandText = string.Empty;
 
 #if NET6_0_OR_GREATER
@@ -67,7 +69,7 @@ public override int ExecuteNonQuery()
     {
         EnsureConnectionOpen();
 
-        var results = PreparedStatement.PrepareMultiple(connection!.NativeConnection, CommandText, parameters);
+        var results = PreparedStatement.PrepareMultiple(connection!.NativeConnection, CommandText, parameters, UseStreamingMode);
 
         var count = 0;
 
@@ -102,7 +104,7 @@ protected override DbDataReader ExecuteDbDataReader(CommandBehavior behavior)
     {
         EnsureConnectionOpen();
 
-        var results = PreparedStatement.PrepareMultiple(connection!.NativeConnection, CommandText, parameters);
+        var results = PreparedStatement.PrepareMultiple(connection!.NativeConnection, CommandText, parameters, UseStreamingMode);
 
         var reader = new DuckDBDataReader(this, results, behavior);
 

DuckDB.NET.Data/DuckDBDataReader.cs

@@ -28,7 +28,7 @@ public class DuckDBDataReader : DbDataReader
     private long currentChunkIndex;
 
     private readonly IEnumerator<DuckDBResult> resultEnumerator;
-    private VectorDataReaderBase[] vectorReaders = Array.Empty<VectorDataReaderBase>();
+    private VectorDataReaderBase[] vectorReaders = [];
 
     internal DuckDBDataReader(DuckDBCommand command, IEnumerable<DuckDBResult> queryResults, CommandBehavior behavior)
     {

DuckDB.NET.Data/Internal/PreparedStatement.cs

@@ -41,7 +41,7 @@ private PreparedStatement(DuckDBPreparedStatement statement)
         this.statement = statement;
     }
 
-    public static IEnumerable<DuckDBResult> PrepareMultiple(DuckDBNativeConnection connection, string query, DuckDBParameterCollection parameters)
+    public static IEnumerable<DuckDBResult> PrepareMultiple(DuckDBNativeConnection connection, string query, DuckDBParameterCollection parameters, bool useStreamingMode)
     {
         using var unmanagedQuery = query.ToUnmanagedString();
 
@@ -62,7 +62,7 @@ public static IEnumerable<DuckDBResult> PrepareMultiple(DuckDBNativeConnection c
                 using var preparedStatement = new PreparedStatement(statement);
                 if (status.IsSuccess())
                 {
-                    using var result = preparedStatement.Execute(parameters);
+                    using var result = preparedStatement.Execute(parameters, useStreamingMode);
                     yield return result;
                 }
                 else
@@ -75,11 +75,14 @@ public static IEnumerable<DuckDBResult> PrepareMultiple(DuckDBNativeConnection c
         }
     }
 
-    public DuckDBResult Execute(DuckDBParameterCollection parameterCollection)
+    public DuckDBResult Execute(DuckDBParameterCollection parameterCollection, bool useStreamingMode)
     {
         BindParameters(statement, parameterCollection);
 
-        var status = NativeMethods.PreparedStatements.DuckDBExecutePreparedStreaming(statement, out var queryResult);
+        var status = useStreamingMode
+            ? NativeMethods.PreparedStatements.DuckDBExecutePreparedStreaming(statement, out var queryResult)
+            : NativeMethods.PreparedStatements.DuckDBExecutePrepared(statement, out queryResult);
+
         if (!status.IsSuccess())
         {
             var errorMessage = NativeMethods.Query.DuckDBResultError(ref queryResult).ToManagedString(false);

DuckDB.NET.Test/DuckDBDataReaderTests.cs

@@ -17,6 +17,7 @@ public void GetOrdinalReturnsColumnIndex()
         Command.ExecuteNonQuery();
 
         Command.CommandText = "select * from GetOrdinalTests";
+        Command.UseStreamingMode = true;
         var reader = Command.ExecuteReader();
 
         reader.GetOrdinal("key").Should().Be(0);
@@ -128,7 +129,7 @@ public void ReadIntervalValues()
         reader.Invoking(r => r.GetValue(0)).Should().Throw<ArgumentOutOfRangeException>();
 
         interval.Months.Should().Be(12);
-        
+
         Command.CommandText = "SELECT INTERVAL '28' DAYS;";
         reader = Command.ExecuteReader();
         reader.Read();
@@ -302,6 +303,7 @@ public void ReadInsertReturningClause()
         Command.CommandText = "CREATE TABLE t2 (i INT, j INT);";
         Command.ExecuteNonQuery();
 
+        Command.UseStreamingMode = true;
         Command.CommandText = @"INSERT INTO t2 
                                     SELECT 2 AS i, 3 AS j 
                                     RETURNING *, i * j AS i_times_j;";
@@ -325,7 +327,7 @@ public void ReadNonQueryAsResult()
     }
 
     [Fact]
-    public void ReadDecimalSchema() 
+    public void ReadDecimalSchema()
     {
         Command.CommandText = "CREATE TABLE decimaltbl(foo decimal(10,2));";
         Command.ExecuteNonQuery();
@@ -342,7 +344,7 @@ public void ReadDecimalSchema()
     }
 
     [Fact]
-    public void ReadDecimalSchemaWithoutTableRow() 
+    public void ReadDecimalSchemaWithoutTableRow()
     {
         Command.CommandText = "CREATE TABLE decimaltbl(foo decimal(10,2));";
         Command.ExecuteNonQuery();