SqlConnection GetSchema("DataTypes") method returns wrong datatype for tinyint

[altrive]

SqlConnection's method GetSchema("DataTypes") returns following results for "tinyint" data type

• DataType: System.SByte
• IsUnsigned:True

This result is inconsistent and it seems it should return System.Byte as DataType,
because SQLServer's tinyint data type is defined to be mapped to .NET byte type (0-254)
https://docs.microsoft.com/en-us/dotnet/framework/data/adonet/sql-server-data-type-mappings

Example code to reproduce problems

var conn = new SqlConnection(@"Data Source=(LocalDB)\MSSQLLocalDB;Initial Catalog=TestDB;Integrated Security=True;");
conn.Open();
var rows = conn.GetSchema(DbMetaDataCollectionNames.DataTypes)
                    .Rows
                    .OfType<DataRow>()
                    .Where(p=>(string)p["TypeName"]== "tinyint");
foreach (var row in rows)
{
	Console.WriteLine(String.Format("TypeName:{0,-25} DataType:{1,-30} IsUnsigned:{2,-15}",
	  row["TypeName"],
	  row["DataType"],
	  row["IsUnsigned"]
	));
}
//Output:
//TypeName:tinyint                   DataType:System.SByte                   IsUnsigned:True        

Root cause of problems

It seems SqlConnection GetSchema("DataTypes") method return results from following xml definition file.

https://github.com/dotnet/corefx/blob/master/src/System.Data.SqlClient/src/Resources/System.Data.SqlClient.SqlMetaData.xml#L804

Reproducible environments

I've confirmed this problem occurs following environments

• .NET 4.6.1
• .NET Core 2.0 with System.Data.SqlClient/4.4.0-preview2-25405-01

Note

It seems following issue mentioned this wrong tinyint datatype.
fsprojects/SQLProvider#69

[divega]

As recently announced in the .NET Blog, focus on new SqlClient features an improvements is moving to the new Microsoft.Data.SqlClient package. For this reason, we are moving this issue to the new repo at https://github.com/dotnet/SqlClient. We will still use https://github.com/dotnet/corefx to track issues on other providers like System.Data.Odbc and System.Data.OleDB, and general ADO.NET and .NET data access issues.