C# 与Oracle Data Type Mappings

The following table lists Oracle data types and their mappings to the OracleDataReader.

Oracle data type	.NET Framework data type returned by OracleDataReader.GetValue	OracleClient data type returned by OracleDataReader.GetOracleValue	Remarks
BFILE	Byte[]	OracleBFile
BLOB	Byte[]	OracleLob
CHAR	String	OracleString
CLOB	String	OracleLob
DATE	DateTime	OracleDateTime
FLOAT	Decimal	OracleNumber	This data type is an alias for the NUMBER data type, and is designed so that the OracleDataReaderreturns a System.Decimal or OracleNumber instead of a floating-point value. Using the .NET Framework data type can cause an overflow.
INTEGER	Decimal	OracleNumber	This data type is an alias for the NUMBER(38) data type, and is designed so that theOracleDataReader returns a System.Decimal or OracleNumber instead of an integer value. Using the .NET Framework data type can cause an overflow.
INTERVAL YEAR TO MONTH	Int32	OracleMonthSpan
INTERVAL DAY TO SECOND	TimeSpan	OracleTimeSpan
LONG	String	OracleString
LONG RAW	Byte[]	OracleBinary
NCHAR	String	OracleString
NCLOB	String	OracleLob
NUMBER	Decimal	OracleNumber	Using the .NET Framework data type can cause an overflow.
NVARCHAR2	String	OracleString
RAW	Byte[]	OracleBinary
REF CURSOR			The Oracle REF CURSOR data type is not supported by the OracleDataReader object.
ROWID	String	OracleString
TIMESTAMP	DateTime	OracleDateTime
TIMESTAMP WITH LOCAL TIME ZONE	DateTime	OracleDateTime
TIMESTAMP WITH TIME ZONE	DateTime	OracleDateTime
UNSIGNED INTEGER	Number	OracleNumber	This data type is an alias for the NUMBER(38) data type, and is designed so that theOracleDataReader returns a System.Decimal or OracleNumber instead of an unsigned integer value. Using the .NET Framework data type can cause an overflow.
VARCHAR2	String	OracleString

The following table lists Oracle data types and the .NET Framework data types (System.Data.DbType and OracleType) to use when binding them as parameters.

Oracle data type	DbType enumeration to bind as a parameter	OracleType enumeration to bind as a parameter	Remarks
BFILE		BFile	Oracle only allows binding a BFILE as a BFILE parameter. The .NET Data Provider for Oracle does not automatically construct one for you if you attempt to bind a non-BFILE value, such as byte[] or OracleBinary.
BLOB		Blob	Oracle only allows binding a BLOB as a BLOB parameter. The .NET Data Provider for Oracle does not automatically construct one for you if you attempt to bind a non-BLOB value, such as byte[] or OracleBinary.
CHAR	AnsiStringFixedLength	Char
CLOB		Clob	Oracle only allows binding a CLOB as a CLOB parameter. The .NET Data Provider for Oracle does not automatically construct one for you if you attempt to bind a non-CLOB value, such as System.String or OracleString.
DATE	DateTime	DateTime
FLOAT	Single, Double, Decimal	Float, Double, Number	Size determines the System.Data.DBType and OracleType.
INTEGER	SByte, Int16, Int32, Int64, Decimal	SByte, Int16, Int32, Number	Size determines the System.Data.DBType and OracleType.
INTERVAL YEAR TO MONTH	Int32	IntervalYearToMonth	OracleType is only available when using both Oracle 9i client and server software.
INTERVAL DAY TO SECOND	Object	IntervalDayToSecond	OracleType is only available when using both Oracle 9i client and server software.
LONG	AnsiString	LongVarChar
LONG RAW	Binary	LongRaw
NCHAR	StringFixedLength	NChar
NCLOB		NClob	Oracle only allows binding a NCLOB as a NCLOB parameter. The .NET Data Provider for Oracle does not automatically construct one for you if you attempt to bind a non-NCLOB value, such as System.String orOracleString.
NUMBER	VarNumeric	Number
NVARCHAR2	String	NVarChar
RAW	Binary	Raw
REF CURSOR		Cursor	For more information, see Oracle REF CURSORs.
ROWID	AnsiString	Rowid
TIMESTAMP	DateTime	Timestamp	OracleType is only available when using both Oracle 9i client and server software.
TIMESTAMP WITH LOCAL TIME ZONE	DateTime	TimestampLocal	OracleType is only available when using both Oracle 9i client and server software.
TIMESTAMP WITH TIME ZONE	DateTime	TimestampWithTz	OracleType is only available when using both Oracle 9i client and server software.
UNSIGNED INTEGER	Byte, UInt16, UInt32, UInt64, Decimal	Byte, UInt16, Uint32, Number	Size determines the System.Data.DBType and OracleType.
VARCHAR2	AnsiString	VarChar

The InputOutput, Output, and ReturnValue ParameterDirection values used by the Value property of the OracleParameter object are .NET Framework data types, unless the input value is an Oracle data type (for example, OracleNumber or OracleString). This does not apply to REF CURSOR, BFILE, or LOB data types.