The ADO.NET Specifications utilizes three different Type Declarations:

1. .NET Type, for example Type object for System.Int32, System.Decimal and Teradata.Client.Provider.TdDecimal. The TdDataReader.GetFieldType and TdDataReader.GetProviderSpecificFieldType methods return a System.Type object.

2. ADO.NET DB Type (System.Data.DbType), for example DbType.Int32, DbType.Decimal and DbType.DateTime. DbType is used to declare the type of Parameters (TdParameter.DbType ).

3. Provider Type (TdType), for example TdType.Integer, TdType.Decimal and TdType.Timestamp. Provider Type is used to declare the type of Parameters (TdParameter.TdType) or identify the data type returned by TdDataReader (TdDataReader.GetSchemaTable) class.

The ADO.NET Specification supports two groups of Data Types:

1. Base Class Library (BCL) Types that comply to the Common Language Specification (CLS). These types include System.Byte, System.Int16, System.Int32, System.Int64, System.Char, System.Single, System.Double, System.Boolean, System.Decimal, Sysetm.String and System.Object. BCL types are accessible from TdDataReader.GetValue, TdDataReader.GetValues, TdParameter.Value and Typed Accessor methods.

2. Provider Specific Types that comply to the Common Language Specification, for example TdDecimal value type. Refer to the .NET Data Provider for Teradata Provider Specific Types for additional information. Provider Specific types are accessible from TdDataReader.GetProviderSpecificValue, TdDataReader.GetProviderSpecificValues, TdParametere.ProviderSpecificValue and Typed Accessor methods.

Some Provider Specific types do not have a corresponding DbType type declaration or BCL type. For example the Teradata Database 13.0 and higher supports PERIOD data types and the .NET Data Provider for Teradata version 13.0 and higher has PERIOD Provider Specific Types (e.g. TdPeriodDate). The Data Provider supports conversion from Provider Specific type to System.String whenever possible.

The following tables shows the mapping of the SQL types to BCL types, DbType and TdType type declarations.

	SQL Type	TdType Enumeration	BCL Type	DbType Enumeration
Character and CLOB Data Types	Char	Char	String Char[]	StringFixedLength
	Clob	Clob	String Char[]	String
	Graphic	Graphic	String Char[]	StringFixedLength
	Json	Json	String Char[]	Json
	VarChar	VarChar	String Char[]	String
	VarGraphic	VarChar	String Char[]	String
Byte and BLOB Data Types	Blob	Blob	Byte[]	Binary
	Byte	Byte	Byte[]	Binary
	VarByte	VarByte	Byte[]	Binary
Numeric Data Types	BigInt	BigInt	Int64	Int64
	ByteInt	ByteInt	Int16	SByte
	Decimal	Decimal	Decimal	Decimal
	Double	Double	Double	Double
	Integer	Integer	Int32	Int32
	Number	Number	Double	Double
	SmallInt	SmallInt	Int16	Int16
Date and Time Data Types	Date	Date	DateTime	Date
	Time	Time	TimeSpan	Time
	Time With Time Zone	TimeWithZone	String	String
	Timestamp	Timestamp	DateTime	DateTime
	Timestamp With Time Zone	TimestampWithZone	DateTimeOffset	DateTimeOffset
Interval Data Types	Interval Day	IntervalDay	TimeSpan	Object
	Interval Day To Hour	IntervalDayToHour	TimeSpan	Object
	Interval Day To Minute	IntervalDayToMinute	TimeSpan	Object
	Interval Day To Second	IntervalDayToSecond	TimeSpan	Object
	Interval Hour	IntervalHour	TimeSpan	Object
	Interval Hour To Minute	IntervalHourToMinute	TimeSpan	Object
	Interval Hour To Second	IntervalHourToSecond	TimeSpan	Object
	Interval Minute	IntervalMinute	TimeSpan	Object
	Interval Minute To Second	IntervalMinuteToSecond	TimeSpan	Object
	Interval Second	IntervalSecond	TimeSpan	Object
	Interval Year	IntervalYear	String	StringFixedLength
	Interval Year To Month	IntervalYearToMonth	String	StringFixedLength
	Interval Month	IntervalMonth	String	StringFixedLength
Period Data Types	Period(Date)	PeriodDate	String	String
	Period(Time)	PeriodTime	String	String
	Period(Time With Time Zone)	PeriodTimeWithZone	String	String
	Period(Timestamp)	PeriodTimestamp	String	String
	Period(Timestamp With Time Zone)	PeriodTimestampWithTimeZone	String	String
TD_ANYTYPE Data Types	TD_ANYTYPE	TdAnyType	See note below	object
Xml	Xml	Xml	String Char[]	Xml

Note
BOLD DbType Enumeration values in the table above show the primary mapping for DbType value to the SQL data type. The Data Provider will use the primary DbType mapping when TdParameter.DbType property is used to specify the Parameter Data Type.

Note
TdType Enumeration does not have a member corresponding to User Defined Types (UDT), User Defined Array Types, Geospatial Types or Dataset Avro. The SQL Engine transforms the aforementioned types to and from predefined SQL types.

Note
TD_ANYTYPE supports character and CLOB, byte and BLOB, numeric, date and time, and interval data types. See the BCL types for these supported data types.