GetOrdinal: case-insensitive fallback and IndexOutOfRangeException

DuckDB.NET.Data/DuckDBDataReader.cs

@@ -1,5 +1,6 @@
 using DuckDB.NET.Data.DataChunk.Reader;
 using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
 using System.IO;
 using System.Runtime.CompilerServices;
 
@@ -249,7 +250,19 @@ public override int GetOrdinal(string name)
             return index;
         }
 
-        throw new DuckDBException($"Column with name {name} was not found.");
+        // IDataRecord.GetOrdinal: "performs a case-sensitive lookup first. If it fails, a second case-insensitive search
+        // is made. GetOrdinal is kana-width insensitive. If the index of the named field is not found, an
+        // IndexOutOfRangeException is thrown."
+        var compareInfo = CultureInfo.InvariantCulture.CompareInfo;
+        for (var i = 0; i < vectorReaders.Length; i++)
+        {
+            if (compareInfo.Compare(vectorReaders[i].ColumnName, name, CompareOptions.IgnoreCase | CompareOptions.IgnoreKanaType | CompareOptions.IgnoreWidth) == 0)
+            {
+                return i;
+            }
+        }
+
+        throw new IndexOutOfRangeException($"Column with name {name} was not found.");
     }
 
     public override string GetString(int ordinal)

DuckDB.NET.Test/DuckDBDataReaderTests.cs

@@ -53,7 +53,7 @@ public void GetOrdinalReturnsColumnIndex()
         reader.GetOrdinal("key").Should().Be(0);
         reader.GetOrdinal("value").Should().Be(1);
 
-        reader.Invoking(dataReader => dataReader.GetOrdinal("Random")).Should().Throw<DuckDBException>();
+        reader.Invoking(dataReader => dataReader.GetOrdinal("Random")).Should().Throw<IndexOutOfRangeException>();
     }
 
     [Fact]
@@ -69,7 +69,7 @@ public void GetOrdinalRepeatedColumnReturnsFirstIndex()
         reader.GetOrdinal("key").Should().Be(1);
         reader.GetOrdinal("value").Should().Be(0);
 
-        reader.Invoking(dataReader => dataReader.GetOrdinal("Random")).Should().Throw<DuckDBException>();
+        reader.Invoking(dataReader => dataReader.GetOrdinal("Random")).Should().Throw<IndexOutOfRangeException>();
     }
 
     [Fact]
@@ -819,4 +819,29 @@ public void ReadIntegerAsAnotherIntegerType()
         reader.Invoking(r => r.GetFieldValue<ulong>(1)).Should().Throw<InvalidCastException>().WithMessage("Cannot cast from Int32 to UInt64 in column negative");
         reader.Invoking(r => r.GetFieldValue<byte>(2)).Should().Throw<InvalidCastException>().WithMessage("Cannot cast from Int16 to Byte in column small");
     }
+
+    // https://learn.microsoft.com/dotnet/api/system.data.idatarecord.getordinal: "GetOrdinal performs a case-sensitive
+    // lookup first. If it fails, a second case-insensitive search is made. GetOrdinal is kana-width insensitive. If the
+    // index of the named field is not found, an IndexOutOfRangeException is thrown."
+    [Fact]
+    public void GetOrdinalFallsBackToACaseInsensitiveMatch()
+    {
+        Command.CommandText = "SELECT 1 AS Id, 2 AS id, 3 AS \"Name\"";
+        using var reader = Command.ExecuteReader();
+
+        reader.GetOrdinal("Id").Should().Be(0);
+        reader.GetOrdinal("id").Should().Be(1, "an exact match wins over a case-insensitive one");
+        reader.GetOrdinal("NAME").Should().Be(2);
+        reader.GetOrdinal("ｎａｍｅ").Should().Be(2, "the lookup is width insensitive");
+    }
+
+    [Fact]
+    public void GetOrdinalThrowsIndexOutOfRangeForAnUnknownName()
+    {
+        Command.CommandText = "SELECT 1 AS Id";
+        using var reader = Command.ExecuteReader();
+
+        reader.Invoking(r => r.GetOrdinal("missing")).Should().Throw<IndexOutOfRangeException>();
+    }
 }
+