Switch to 0-based column ordinals.

This is a breaking change with Connector/NET, but its behaviour doesn't match the MSDN documentation, nor other methods on DbDataReader (which use 0-based column ordinals).

Author: bgrainger

docs/content/tutorials/migrating-from-connector-net.md

@@ -74,6 +74,7 @@ property doesn't reference the active transaction. See [#333](https://github.com
 
 * [#37283](https://bugs.mysql.com/bug.php?id=37283), [#70587](https://bugs.mysql.com/bug.php?id=70587): Distributed transactions are not supported
 * [#50773](https://bugs.mysql.com/bug.php?id=50773): Can't use multiple connections within one TransactionScope
+* [#61477](https://bugs.mysql.com/bug.php?id=61477): `ColumnOrdinal` in schema table is 1-based
 * [#66476](https://bugs.mysql.com/bug.php?id=66476): Connection pool uses queue instead of stack
 * [#70111](https://bugs.mysql.com/bug.php?id=70111): `Async` methods execute synchronously
 * [#70686](https://bugs.mysql.com/bug.php?id=70686): `TIME(3)` and `TIME(6)` fields serialize milliseconds incorrectly

src/MySqlConnector/MySqlClient/MySqlDataReader.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Data;
@@ -344,7 +344,7 @@ internal DataTable BuildSchemaTable()
 				var col = colDefinitions[i];
 				var schemaRow = schemaTable.NewRow();
 				schemaRow[columnName] = col.Name;
-				schemaRow[ordinal] = i + 1; // https://bugs.mysql.com/bug.php?id=61477
+				schemaRow[ordinal] = i;
 				schemaRow[dataType] = GetFieldType(i);
 				schemaRow[size] = (Type)schemaRow[dataType] == typeof(string) || (Type)schemaRow[dataType] == typeof(Guid) ?
 					col.ColumnLength / SerializationUtility.GetBytesPerCharacter(col.CharacterSet) :

tests/SideBySide/DataTypes.cs

@@ -619,12 +619,18 @@ public void GetSchemaTable(string column, string table, int columnSize, Type dat
 		{
 			using (var command = m_database.Connection.CreateCommand())
 			{
-				command.CommandText = $"select 1, `{column}` from `{table}`;";
+				command.CommandText = $"select `{column}` from `{table}`;";
 				using (var reader = command.ExecuteReader())
 				{
-					var schema = reader.GetSchemaTable().Rows[1];
+					var schemaTable = reader.GetSchemaTable();
+					Assert.Single(schemaTable.Rows);
+					var schema = schemaTable.Rows[0];
 					Assert.Equal(column, schema["ColumnName"]);
-					int ordinal = 2; // https://bugs.mysql.com/bug.php?id=61477
+#if BASELINE
+					int ordinal = 1; // https://bugs.mysql.com/bug.php?id=61477
+#else
+					int ordinal = 0;
+#endif
 					Assert.Equal(ordinal, schema["ColumnOrdinal"]);
 					Assert.Equal(dataType, schema["DataType"]);
 					Assert.Equal(columnSize, schema["ColumnSize"]);
@@ -644,7 +650,7 @@ public void GetSchemaTable(string column, string table, int columnSize, Type dat
 		}
 #endif
 
-		private static byte[] CreateByteArray(int size)
+					private static byte[] CreateByteArray(int size)
 		{
 			var data = new byte[size];
 			Random random = new Random(size);