Supported Conversions

Before the consumer creates an accessor, it can call IConvertType::CanConvert to determine if the provider supports a particular conversion.

Default Data Type Mapping

The OpenLink Provider binds to the ODBC/UDBC data source using the types in the table below. The SQL type is queried using SQLDescribeCol. The sign of the data type (signed/unsigned) is determined using SQLColAttributes. It is used in deciding which C type to use in internal buffers and which type indicator to return through IColumnsInfo::GetColumnInfo.

Table: 5.7.9.1.1. OLE-DB Data Type Mappings

SQL Type Indicator	Indicator of C Type Used For Internal Buffers	OLE DB Type Indicator
SQL_TINYINT, SQL_SMALLINT	SQL_C_USHORT, SQL_C_SSHORTS	DBTYPE_I2
SQL_INTEGER	SQL_C_ULONG, SQL_C_SLONG	DBTYPE_I4
SQL_TIMESTAMP	SQL_C_TIMESTAMP	DBTYPE_DATE
SQL_TIME	SQL_C_TIME	DBTYPE_DATE
SQL_BIGINT	SQL_C_STR	DBTYPE_STR
SQL_REAL	SQL_C_FLOAT	DBTYPE_R4
SQL_FLOAT, SQL_DOUBLE	SQL_C_DOUBLE	DBTYPE_R8
SQL_DATE	SQL_C_DATE	DBTYPE_DATE
SQL_BIT	SQL_C_BIT	DBTYPE_BOOL
SQL_BINARY, SQL_VARBINARY, SQL_LONGVARBINARY	SQL_C_BINARY	DBTYPE_BYTES
SQL_CHAR, SQL_VARCHAR, SQL_LONGVARCHAR, SQL_DECIMAL, SQL_NUMERIC	SQL_C_CHAR	DBTYPE_STR

Length Binding

For types DBTYPE_UI1, DBTYPE_I2, DBTYPE_I4, DBTYPE_I8, DBTYPE_R4, DBTYPE_R8, DBTYPE_CY, DBTYPE_NUMERIC, the length binding is always set to the fixed size of the destination binding type, rather than the internal source type.

Supported Data Conversions

The follwoing table outlines the supported type conversion implemented in the OpenLink provider. An 'X' means supported, and '-' means not supported.

Table: 5.7.9.3.1. OLE-DB Data Type Conversions

I1

I2

I4

I8

UI1

UI2

UI4

UI8

R4

R8

CY

DEC

NUM

BOOL

DATE

DBDATE

DBTIMESTAMP

DBTIME

BYTES

BSTR

STR

WSTR

DISP

UNK

GUID

I1

X

X

X

X

X

X

X

X

X

X

X

X

X

-

-

-

-

-

X

X

X

X

-

-

-

I2

X

X

X

X

X

X

X

X

X

X

X

X

X

-

-

-

-

-

X

X

X

X

-

-

-

I4

X

X

X

X

X

X

X

X

X

X

X

X

X

-

-

-

-

-

X

X

X

X

-

-

-

I8

X

X

X

X

X

X

X

X

X

X

X

X

X

-

-

-

-

-

X

X

X

X

-

-

-

UI1

X

X

X

X

X

X

X

X

X

X

X

X

X

-

-

-

-

-

X

X

X

X

-

-

-

UI2

X

X

X

X

X

X

X

X

X

X

X

X

X

-

-

-

-

-

X

X

X

X

-

-

-

UI4

X

X

X

X

X

X

X

X

X

X

X

X

X

-

-

-

-

-

X

X

X

X

-

-

-

UI8

X

X

X

X

X

X

X

X

X

X

X

X

X

-

-

-

-

-

X

X

X

X

-

-

-

R4

X

X

X

X

X

X

X

X

X

X

X

X

X

-

-

-

-

-

X

X

X

X

-

-

-

R8

X

X

X

X

X

X

X

X

X

X

X

X

X

-

-

-

-

-

X

X

X

X

-

-

-

CY

X

X

X

X

X

X

X

X

X

X

X

X

X

-

-

-

-

-

X

X

X

X

-

-

-

DEC

X

X

X

X

X

X

X

X

X

X

X

X

X

-

-

-

-

-

X

X

X

X

-

-

-

NUM

X

X

X

X

X

X

X

X

X

X

X

X

X

-

-

-

-

-

X

X

X

X

-

-

-

BOOL

-

-

-

-

-

-

-

-

-

-

-

-

-

X

-

-

-

-

X

X

X

X

-

-

-

DATE

-

-

-

-

-

-

-

-

-

-

-

-

-

-

X

X

X

X

X

X

X

X

-

-

-

DBDATE

-

-

-

-

-

-

-

-

-

-

-

-

-

-

X

X

-

X

X

X

X

X

-

-

-

DBTIME

-

-

-

-

-

-

-

-

-

-

-

-

-

-

X

-

X

X

X

X

X

X

-

-

-

DBTIMESTAMP

-

-

-

-

-

-

-

-

-

-

-

-

-

-

X

X

X

X

X

X

X

X

-

-

-

BYTES

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

-

X

X

X

X

X

X

X

X

BSTR

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

-

-

X

STR

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

-

X

X

WSTR

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

-

X

X

DISP

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

X

-

-

-

X

X

-

UNK

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

X

-

-

-

-

X

-

GUID

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

X

X

X

X

-

-

X