// SqlDbType轉換為C#數據類型
public static Type SqlType2CsharpType(SqlDbType sqlType)
{
switch (sqlType)
{
       case SqlDbType.BigInt:
         return typeof(Int64);
       case SqlDbType.Binary:
         return typeof(Object);
       case SqlDbType.Bit:
         return typeof(Boolean);
       case SqlDbType.Char:
         return typeof(String);
       case SqlDbType.DateTime:
         return typeof(DateTime);
       case SqlDbType.Decimal:
         return typeof(Decimal);
       case SqlDbType.Float:
         return typeof(Double);
       case SqlDbType.Image:
         return typeof(Object);
       case SqlDbType.Int:
         return typeof(Int32);
       case SqlDbType.Money:
         return typeof(Decimal);
       case SqlDbType.NChar:
         return typeof(String);
       case SqlDbType.NText:
         return typeof(String);
       case SqlDbType.NVarChar:
         return typeof(String);
       case SqlDbType.Real:
         return typeof(Single);
       case SqlDbType.SmallDateTime:
         return typeof(DateTime);
       case SqlDbType.SmallInt:
         return typeof(Int16);
       case SqlDbType.SmallMoney:
         return typeof(Decimal);
       case SqlDbType.Text:
         return typeof(String);
       case SqlDbType.Timestamp:
         return typeof(Object);
       case SqlDbType.TinyInt:
         return typeof(Byte);
       case SqlDbType.Udt://自定義的數據類型
         return typeof(Object);
       case SqlDbType.UniqueIdentifier:
         return typeof(Object);
       case SqlDbType.VarBinary:
         return typeof(Object);
       case SqlDbType.VarChar:
         return typeof(String);
       case SqlDbType.Variant:
         return typeof(Object);
       case SqlDbType.Xml:
         return typeof(Object);
       default:
         return null;
}
}

// sql server數據類型（如：varchar）
// 轉換為SqlDbType類型
public static SqlDbType SqlTypeString2SqlType(string sqlTypeString)
{
SqlDbType dbType = SqlDbType.Variant;//默認為Object

switch (sqlTypeString)
{
       case "int":
         dbType = SqlDbType.Int;
         break;
       case "varchar":
         dbType = SqlDbType.VarChar;
         break;
       case "bit":
         dbType = SqlDbType.Bit;
         break;
       case "datetime":
         dbType = SqlDbType.DateTime;
         break;
       case "decimal":
         dbType = SqlDbType.Decimal;
         break;
       case "float":
         dbType = SqlDbType.Float;
         break;
       case "image":
         dbType = SqlDbType.Image;
         break;
       case "money":
         dbType = SqlDbType.Money;
         break;
       case "ntext":
         dbType = SqlDbType.NText;
         break;
       case "nvarchar":
         dbType = SqlDbType.NVarChar;
         break;
       case "smalldatetime":
         dbType = SqlDbType.SmallDateTime;
         break;
       case "smallint":
         dbType = SqlDbType.SmallInt;
         break;
       case "text":
         dbType = SqlDbType.Text;
         break;
       case "bigint":
         dbType = SqlDbType.BigInt;
         break;
       case "binary":
         dbType = SqlDbType.Binary;
         break;
       case "char":
         dbType = SqlDbType.Char;
         break;
       case "nchar":
         dbType = SqlDbType.NChar;
         break;
       case "numeric":
         dbType = SqlDbType.Decimal;
         break;
       case "real":
         dbType = SqlDbType.Real;
         break;
       case "smallmoney":
         dbType = SqlDbType.SmallMoney;
         break;
       case "sql_variant":
         dbType = SqlDbType.Variant;
         break;
       case "timestamp":
         dbType = SqlDbType.Timestamp;
         break;
       case "tinyint":
         dbType = SqlDbType.TinyInt;
         break;
       case "uniqueidentifier":
         dbType = SqlDbType.UniqueIdentifier;
         break;
       case "varbinary":
         dbType = SqlDbType.VarBinary;
         break;
       case "xml":
         dbType = SqlDbType.Xml;
         break;
}
return dbType;
}

// sql server中的數據類型，轉換為C#中的類型類型
public static Type SqlTypeString2CsharpType(string sqlTypeString)
{
SqlDbType dbTpe = SqlTypeString2SqlType(sqlTypeString);

return SqlType2CsharpType(dbTpe);
}

// 將sql server中的數據類型，轉化為C#中的類型的字符串
public static string SqlTypeString2CsharpTypeString(string sqlTypeString)
{
Type type = SqlTypeString2CsharpType(sqlTypeString);

return type.Name;
}

?

有如下類型的映射對照：

System.Data.SqlClient.SqlDbType
System.Data.OleDb.OleDbType
System.Data.Odbc.OdbcType
System.Data.OracleClient.OracleType
Oracle.ManagedDataAccess.ClientOracleDbType
格式：

DbType.枚舉名（枚舉值） = DbType.枚舉名（枚舉值）

回到頂部
1、與 System.Data.SqlClient.SqlDbType轉換
System.Data.SqlClient.SqlDbType.BigInt(0)   =  System.Data.DbType.Int64(12)
System.Data.SqlClient.SqlDbType.Binary(1)   =  System.Data.DbType.Binary(1)
System.Data.SqlClient.SqlDbType.Bit(2)   =  System.Data.DbType.Boolean(3)
System.Data.SqlClient.SqlDbType.Char(3)   =  System.Data.DbType.AnsiStringFixedLength(22)
System.Data.SqlClient.SqlDbType.DateTime(4)   =  System.Data.DbType.DateTime(6)
System.Data.SqlClient.SqlDbType.Decimal(5)   =  System.Data.DbType.Decimal(7)
System.Data.SqlClient.SqlDbType.Float(6)   =  System.Data.DbType.Double(8)
System.Data.SqlClient.SqlDbType.Image(7)   =  System.Data.DbType.Binary(1)
System.Data.SqlClient.SqlDbType.Int(8)   =  System.Data.DbType.Int32(11)
System.Data.SqlClient.SqlDbType.Money(9)   =  System.Data.DbType.Currency(4)
System.Data.SqlClient.SqlDbType.NChar(10)   =  System.Data.DbType.StringFixedLength(23)
System.Data.SqlClient.SqlDbType.NText(11)   =  System.Data.DbType.String(16)
System.Data.SqlClient.SqlDbType.NVarChar(12)   =  System.Data.DbType.String(16)
System.Data.SqlClient.SqlDbType.Real(13)   =  System.Data.DbType.Single(15)
System.Data.SqlClient.SqlDbType.UniqueIdentifier(14)   =  System.Data.DbType.Guid(9)
System.Data.SqlClient.SqlDbType.SmallDateTime(15)   =  System.Data.DbType.DateTime(6)
System.Data.SqlClient.SqlDbType.SmallInt(16)   =  System.Data.DbType.Int16(10)
System.Data.SqlClient.SqlDbType.SmallMoney(17)   =  System.Data.DbType.Currency(4)
System.Data.SqlClient.SqlDbType.Text(18)   =  System.Data.DbType.AnsiString(0)
System.Data.SqlClient.SqlDbType.Timestamp(19)   =  System.Data.DbType.Binary(1)
System.Data.SqlClient.SqlDbType.TinyInt(20)   =  System.Data.DbType.Byte(2)
System.Data.SqlClient.SqlDbType.VarBinary(21)   =  System.Data.DbType.Binary(1)
System.Data.SqlClient.SqlDbType.VarChar(22)   =  System.Data.DbType.AnsiString(0)
System.Data.SqlClient.SqlDbType.Variant(23)   =  System.Data.DbType.Object(13)
System.Data.SqlClient.SqlDbType.Xml(25)   =  System.Data.DbType.Xml(25)
System.Data.SqlClient.SqlDbType.Udt(29)   =  System.Data.DbType.Object(13)
System.Data.SqlClient.SqlDbType.Structured(30)   =  System.Data.DbType.Object(13)
System.Data.SqlClient.SqlDbType.Date(31)   =  System.Data.DbType.Date(5)
System.Data.SqlClient.SqlDbType.Time(32)   =  System.Data.DbType.Time(17)
System.Data.SqlClient.SqlDbType.DateTime2(33)   =  System.Data.DbType.DateTime2(26)
System.Data.SqlClient.SqlDbType.DateTimeOffset(34)   =  System.Data.DbType.DateTimeOffset(27)

回到頂部
2、與 System.Data.OleDb.OleDbType轉換
System.Data.OleDb.OleDbType.Empty(0)   =  System.Data.DbType.Object(13)
System.Data.OleDb.OleDbType.SmallInt(2)   =  System.Data.DbType.Int16(10)
System.Data.OleDb.OleDbType.Integer(3)   =  System.Data.DbType.Int32(11)
System.Data.OleDb.OleDbType.Single(4)   =  System.Data.DbType.Single(15)
System.Data.OleDb.OleDbType.Double(5)   =  System.Data.DbType.Double(8)
System.Data.OleDb.OleDbType.Currency(6)   =  System.Data.DbType.Currency(4)
System.Data.OleDb.OleDbType.Date(7)   =  System.Data.DbType.DateTime(6)
System.Data.OleDb.OleDbType.BSTR(8)   =  System.Data.DbType.String(16)
System.Data.OleDb.OleDbType.IDispatch(9)   =  System.Data.DbType.Object(13)
System.Data.OleDb.OleDbType.Error(10)   =  System.Data.DbType.Int32(11)
System.Data.OleDb.OleDbType.Boolean(11)   =  System.Data.DbType.Boolean(3)
System.Data.OleDb.OleDbType.Variant(12)   =  System.Data.DbType.Object(13)
System.Data.OleDb.OleDbType.IUnknown(13)   =  System.Data.DbType.Object(13)
System.Data.OleDb.OleDbType.Decimal(14)   =  System.Data.DbType.Decimal(7)
System.Data.OleDb.OleDbType.TinyInt(16)   =  System.Data.DbType.SByte(14)
System.Data.OleDb.OleDbType.UnsignedTinyInt(17)   =  System.Data.DbType.Byte(2)
System.Data.OleDb.OleDbType.UnsignedSmallInt(18)   =  System.Data.DbType.UInt16(18)
System.Data.OleDb.OleDbType.UnsignedInt(19)   =  System.Data.DbType.UInt32(19)
System.Data.OleDb.OleDbType.BigInt(20)   =  System.Data.DbType.Int64(12)
System.Data.OleDb.OleDbType.UnsignedBigInt(21)   =  System.Data.DbType.UInt64(20)
System.Data.OleDb.OleDbType.Filetime(64)   =  System.Data.DbType.DateTime(6)
System.Data.OleDb.OleDbType.Guid(72)   =  System.Data.DbType.Guid(9)
System.Data.OleDb.OleDbType.Binary(128)   =  System.Data.DbType.Binary(1)
System.Data.OleDb.OleDbType.Char(129)   =  System.Data.DbType.AnsiStringFixedLength(22)
System.Data.OleDb.OleDbType.WChar(130)   =  System.Data.DbType.StringFixedLength(23)
System.Data.OleDb.OleDbType.Numeric(131)   =  System.Data.DbType.Decimal(7)
System.Data.OleDb.OleDbType.DBDate(133)   =  System.Data.DbType.Date(5)
System.Data.OleDb.OleDbType.DBTime(134)   =  System.Data.DbType.Time(17)
System.Data.OleDb.OleDbType.DBTimeStamp(135)   =  System.Data.DbType.DateTime(6)
System.Data.OleDb.OleDbType.PropVariant(138)   =  System.Data.DbType.Object(13)
System.Data.OleDb.OleDbType.VarNumeric(139)   =  System.Data.DbType.VarNumeric(21)
System.Data.OleDb.OleDbType.VarChar(200)   =  System.Data.DbType.AnsiString(0)
System.Data.OleDb.OleDbType.LongVarChar(201)   =  System.Data.DbType.AnsiString(0)
System.Data.OleDb.OleDbType.VarWChar(202)   =  System.Data.DbType.String(16)
System.Data.OleDb.OleDbType.LongVarWChar(203)   =  System.Data.DbType.String(16)
System.Data.OleDb.OleDbType.VarBinary(204)   =  System.Data.DbType.Binary(1)
System.Data.OleDb.OleDbType.LongVarBinary(205)   =  System.Data.DbType.Binary(1)

回到頂部
3、與System.Data.Odbc.OdbcType轉換
System.Data.Odbc.OdbcType.BigInt(1)   =  System.Data.DbType.Int64(12)
System.Data.Odbc.OdbcType.Binary(2)   =  System.Data.DbType.Binary(1)
System.Data.Odbc.OdbcType.Bit(3)   =  System.Data.DbType.Boolean(3)
System.Data.Odbc.OdbcType.Char(4)   =  System.Data.DbType.AnsiStringFixedLength(22)
System.Data.Odbc.OdbcType.DateTime(5)   =  System.Data.DbType.DateTime(6)
System.Data.Odbc.OdbcType.Decimal(6)   =  System.Data.DbType.Decimal(7)
System.Data.Odbc.OdbcType.Numeric(7)   =  System.Data.DbType.Decimal(7)
System.Data.Odbc.OdbcType.Double(8)   =  System.Data.DbType.Double(8)
System.Data.Odbc.OdbcType.Image(9)   =  System.Data.DbType.Binary(1)
System.Data.Odbc.OdbcType.Int(10)   =  System.Data.DbType.Int32(11)
System.Data.Odbc.OdbcType.NChar(11)   =  System.Data.DbType.StringFixedLength(23)
System.Data.Odbc.OdbcType.NText(12)   =  System.Data.DbType.String(16)
System.Data.Odbc.OdbcType.NVarChar(13)   =  System.Data.DbType.String(16)
System.Data.Odbc.OdbcType.Real(14)   =  System.Data.DbType.Single(15)
System.Data.Odbc.OdbcType.UniqueIdentifier(15)   =  System.Data.DbType.Guid(9)
System.Data.Odbc.OdbcType.SmallDateTime(16)   =  System.Data.DbType.DateTime(6)
System.Data.Odbc.OdbcType.SmallInt(17)   =  System.Data.DbType.Int16(10)
System.Data.Odbc.OdbcType.Text(18)   =  System.Data.DbType.AnsiString(0)
System.Data.Odbc.OdbcType.Timestamp(19)   =  System.Data.DbType.Binary(1)
System.Data.Odbc.OdbcType.TinyInt(20)   =  System.Data.DbType.Byte(2)
System.Data.Odbc.OdbcType.VarBinary(21)   =  System.Data.DbType.Binary(1)
System.Data.Odbc.OdbcType.VarChar(22)   =  System.Data.DbType.AnsiString(0)
System.Data.Odbc.OdbcType.Date(23)   =  System.Data.DbType.Date(5)
System.Data.Odbc.OdbcType.Time(24)   =  System.Data.DbType.Time(17)

回到頂部
4、與System.Data.OracleClient.OracleType轉換
System.Data.OracleClient.OracleType.BFile(1)   =  System.Data.DbType.Binary(1)
System.Data.OracleClient.OracleType.Blob(2)   =  System.Data.DbType.Binary(1)
System.Data.OracleClient.OracleType.Char(3)   =  System.Data.DbType.AnsiStringFixedLength(22)
System.Data.OracleClient.OracleType.Clob(4)   =  System.Data.DbType.AnsiString(0)
System.Data.OracleClient.OracleType.Cursor(5)   =  System.Data.DbType.Object(13)
System.Data.OracleClient.OracleType.DateTime(6)   =  System.Data.DbType.DateTime(6)
System.Data.OracleClient.OracleType.IntervalDayToSecond(7)   =  System.Data.DbType.Object(13)
System.Data.OracleClient.OracleType.IntervalYearToMonth(8)   =  System.Data.DbType.Int32(11)
System.Data.OracleClient.OracleType.LongRaw(9)   =  System.Data.DbType.Binary(1)
System.Data.OracleClient.OracleType.LongVarChar(10)   =  System.Data.DbType.AnsiString(0)
System.Data.OracleClient.OracleType.NChar(11)   =  System.Data.DbType.StringFixedLength(23)
System.Data.OracleClient.OracleType.NClob(12)   =  System.Data.DbType.String(16)
System.Data.OracleClient.OracleType.Number(13)   =  System.Data.DbType.VarNumeric(21)
System.Data.OracleClient.OracleType.NVarChar(14)   =  System.Data.DbType.String(16)
System.Data.OracleClient.OracleType.Raw(15)   =  System.Data.DbType.Binary(1)
System.Data.OracleClient.OracleType.RowId(16)   =  System.Data.DbType.AnsiString(0)
System.Data.OracleClient.OracleType.Timestamp(18)   =  System.Data.DbType.DateTime(6)
System.Data.OracleClient.OracleType.TimestampLocal(19)   =  System.Data.DbType.DateTime(6)
System.Data.OracleClient.OracleType.TimestampWithTZ(20)   =  System.Data.DbType.DateTime(6)
System.Data.OracleClient.OracleType.VarChar(22)   =  System.Data.DbType.AnsiString(0)
System.Data.OracleClient.OracleType.Byte(23)   =  System.Data.DbType.Byte(2)
System.Data.OracleClient.OracleType.UInt16(24)   =  System.Data.DbType.UInt16(18)
System.Data.OracleClient.OracleType.UInt32(25)   =  System.Data.DbType.UInt32(19)
System.Data.OracleClient.OracleType.SByte(26)   =  System.Data.DbType.SByte(14)
System.Data.OracleClient.OracleType.Int16(27)   =  System.Data.DbType.Int16(10)
System.Data.OracleClient.OracleType.Int32(28)   =  System.Data.DbType.Int32(11)
System.Data.OracleClient.OracleType.Float(29)   =  System.Data.DbType.Single(15)
System.Data.OracleClient.OracleType.Double(30)   =  System.Data.DbType.Double(8)

回到頂部
5、與Oracle.ManagedDataAccess.ClientOracleDbType轉換

Oracle.ManagedDataAccess.ClientOracleDbType.BFile =  System.Data.DbType.Binary(1)
Oracle.ManagedDataAccess.ClientOracleDbType.Blob = 102,
Oracle.ManagedDataAccess.ClientOracleDbType.Byte = 103,
Oracle.ManagedDataAccess.ClientOracleDbType.Char = 104,
Oracle.ManagedDataAccess.ClientOracleDbType.Clob = 105,
Oracle.ManagedDataAccess.ClientOracleDbType.Date = 106,
Oracle.ManagedDataAccess.ClientOracleDbType.Decimal = 107,
Oracle.ManagedDataAccess.ClientOracleDbType.Double = 108,
Oracle.ManagedDataAccess.ClientOracleDbType.Long = 109,
Oracle.ManagedDataAccess.ClientOracleDbType.LongRaw = 110,
Oracle.ManagedDataAccess.ClientOracleDbType.Int16 = 111,
Oracle.ManagedDataAccess.ClientOracleDbType.Int32 = 112,
Oracle.ManagedDataAccess.ClientOracleDbType.Int64 = 113,
Oracle.ManagedDataAccess.ClientOracleDbType.IntervalDS = 114,
Oracle.ManagedDataAccess.ClientOracleDbType.IntervalYM = 115,
Oracle.ManagedDataAccess.ClientOracleDbType.NClob = 116,
Oracle.ManagedDataAccess.ClientOracleDbType.NChar = 117,
Oracle.ManagedDataAccess.ClientOracleDbType.NVarchar2 = 119,
Oracle.ManagedDataAccess.ClientOracleDbType.Raw = 120,
Oracle.ManagedDataAccess.ClientOracleDbType.RefCursor = 121,
Oracle.ManagedDataAccess.ClientOracleDbType.Single = 122,
Oracle.ManagedDataAccess.ClientOracleDbType.TimeStamp = 123,
Oracle.ManagedDataAccess.ClientOracleDbType.TimeStampLTZ = 124,
Oracle.ManagedDataAccess.ClientOracleDbType.TimeStampTZ = 125,
Oracle.ManagedDataAccess.ClientOracleDbType.Varchar2 = 126,
Oracle.ManagedDataAccess.ClientOracleDbType.XmlType = 127,
Oracle.ManagedDataAccess.ClientOracleDbType.BinaryDouble = 132,     
Oracle.ManagedDataAccess.ClientOracleDbType.BinaryFloat = 133,
Oracle.ManagedDataAccess.ClientOracleDbType.Boolean = 134,