Make MySqlParameter conform to MSDN documentation.

https://docs.microsoft.com/en-us/dotnet/api/system.data.common.dbparameter.parametername: The default is an empty string ("").

https://docs.microsoft.com/en-us/dotnet/api/system.data.common.dbparameter.sourcecolumn:  The default is an empty string.

Author: bgrainger

src/MySqlConnector/MySql.Data.MySqlClient/MySqlParameter.cs

@@ -11,6 +11,8 @@ public sealed class MySqlParameter : DbParameter
 	{
 		public MySqlParameter()
 		{
+			ParameterName = "";
+			SourceColumn = "";
 #if !NETSTANDARD1_3
 			SourceVersion = DataRowVersion.Current;
 #endif
@@ -30,7 +32,7 @@ public MySqlParameter(string name, MySqlDbType mySqlDbType)
 		}
 
 		public MySqlParameter(string name, MySqlDbType mySqlDbType, int size)
-			: this(name, mySqlDbType, size, null)
+			: this(name, mySqlDbType, size, "")
 		{
 		}
 

tests/SideBySide/ParameterTests.cs

@@ -63,13 +63,16 @@ public void DbTypesToMySqlDbTypes(DbType[] dbTypes, MySqlDbType[] mySqlDbTypes)
 		public void ConstructorSimple()
 		{
 			var parameter = new MySqlParameter();
-			Assert.Null(parameter.ParameterName);
 #if BASELINE
+			Assert.Null(parameter.ParameterName);
 			Assert.Equal(MySqlDbType.Decimal, parameter.MySqlDbType);
 			Assert.Equal(DbType.AnsiString, parameter.DbType);
+			Assert.Null(parameter.SourceColumn);
 #else
+			Assert.Equal("", parameter.ParameterName);
 			Assert.Equal(MySqlDbType.VarChar, parameter.MySqlDbType);
 			Assert.Equal(DbType.String, parameter.DbType);
+			Assert.Equal("", parameter.SourceColumn);
 #endif
 			Assert.False(parameter.IsNullable);
 			Assert.Null(parameter.Value);
@@ -80,7 +83,6 @@ public void ConstructorSimple()
 #if !NETCOREAPP1_1_2
 			Assert.Equal(DataRowVersion.Current, parameter.SourceVersion);
 #endif
-			Assert.Null(parameter.SourceColumn);
 		}
 
 		[Fact]
@@ -99,7 +101,11 @@ public void ConstructorNameValue()
 #if !NETCOREAPP1_1_2
 			Assert.Equal(DataRowVersion.Current, parameter.SourceVersion);
 #endif
+#if BASELINE
 			Assert.Null(parameter.SourceColumn);
+#else
+			Assert.Equal("", parameter.SourceColumn);
+#endif
 		}
 
 		[Fact]
@@ -118,7 +124,11 @@ public void ConstructorNameType()
 #if !NETCOREAPP1_1_2
 			Assert.Equal(DataRowVersion.Current, parameter.SourceVersion);
 #endif
+#if BASELINE
 			Assert.Null(parameter.SourceColumn);
+#else
+			Assert.Equal("", parameter.SourceColumn);
+#endif
 		}
 
 		[Fact]
@@ -137,7 +147,11 @@ public void ConstructorNameTypeSize()
 #if !NETCOREAPP1_1_2
 			Assert.Equal(DataRowVersion.Current, parameter.SourceVersion);
 #endif
+#if BASELINE
 			Assert.Null(parameter.SourceColumn);
+#else
+			Assert.Equal("", parameter.SourceColumn);
+#endif
 		}
 
 		[Fact]