Store MySqlDbType for cached parameters.

Switch to the new MySqlDbType mapping code that was added after this code was created; this should be more accurate than mapping to DbType.

Author: bgrainger

src/MySqlConnector/Core/CachedParameter.cs

@@ -1,5 +1,6 @@
+using System;
 using System.Data;
-using System.Linq;
+using MySql.Data.MySqlClient;
 
 namespace MySqlConnector.Core
 {
@@ -9,31 +10,20 @@ public CachedParameter(int ordinalPosition, string mode, string name, string dat
 		{
 			Position = ordinalPosition;
 			if (Position == 0)
-			{
 				Direction = ParameterDirection.ReturnValue;
-			}
-			else
-			{
-				switch (mode.ToLowerInvariant())
-				{
-					case "in":
-						Direction = ParameterDirection.Input;
-						break;
-					case "inout":
-						Direction = ParameterDirection.InputOutput;
-						break;
-					case "out":
-						Direction = ParameterDirection.Output;
-						break;
-				}
-			}
+			else if (string.Equals(mode, "in", StringComparison.OrdinalIgnoreCase))
+				Direction = ParameterDirection.Input;
+			else if (string.Equals(mode, "inout", StringComparison.OrdinalIgnoreCase))
+				Direction = ParameterDirection.InputOutput;
+			else if (string.Equals(mode, "out", StringComparison.OrdinalIgnoreCase))
+				Direction = ParameterDirection.Output;
 			Name = name;
-			DbType = TypeMapper.Instance.GetDbTypeMapping(dataType, unsigned).DbTypes?.First() ?? DbType.Object;
+			MySqlDbType = TypeMapper.Instance.GetMySqlDbType(dataType, unsigned);
 		}
 
-		internal readonly int Position;
-		internal readonly ParameterDirection Direction;
-		internal readonly string Name;
-		internal readonly DbType DbType;
+		public int Position { get; }
+		public ParameterDirection Direction { get; }
+		public string Name { get; }
+		public MySqlDbType MySqlDbType { get; }
 	}
 }

src/MySqlConnector/Core/CachedProcedure.cs

@@ -79,7 +79,7 @@ internal MySqlParameterCollection AlignParamsWithDb(MySqlParameterCollection par
 				if (!alignParam.HasSetDirection)
 					alignParam.Direction = cachedParam.Direction;
 				if (!alignParam.HasSetDbType)
-					alignParam.DbType = cachedParam.DbType;
+					alignParam.MySqlDbType = cachedParam.MySqlDbType;
 
 				// cached parameters are oredered by ordinal position
 				alignedParams.Add(alignParam);

src/MySqlConnector/Core/TypeMapper.cs

@@ -164,6 +164,8 @@ public DbTypeMapping GetDbTypeMapping(string columnTypeName, bool unsigned = fal
 			return GetColumnTypeMetadata(columnTypeName, unsigned, length)?.DbTypeMapping;
 		}
 
+		public MySqlDbType GetMySqlDbType(string typeName, bool unsigned) => GetColumnTypeMetadata(typeName, unsigned, 0).MySqlDbType;
+
 		private ColumnTypeMetadata GetColumnTypeMetadata(string columnTypeName, bool unsigned, int length)
 		{
 			if (!m_columnTypeMetadataLookup.TryGetValue(ColumnTypeMetadata.CreateLookupKey(columnTypeName, unsigned, length), out var columnTypeMetadata) && length != 0)