Data Type Mapping
OLE DB uses standard OLE and Windows data types. To describe a data type, an OLE DB type indicator is used, which is a variable of the enumerated type DBTYPE. The Teradata OLE DB Access Module retrieves the C/C++ data type indicated by the OLE DB type indicator and converts the data type to a Teradata Database data type. The Teradata Database data type is based on the DBTYPE and the DBCOLUMNFLAGS values.
Data type mapping is required for transferring data from the Teradata OLE DB providers to the Teradata Database. Table 3 lists the mapping of OLE DB type indicators to Teradata Database data types.
|
DBTYPE |
DBCOLUMNFLAG |
Teradata Type |
|
DBTYPE_11 |
|
BYTE(n)* |
|
DBTYPE_I2 |
|
SMALLINT |
|
DBTYPE_I4 |
|
INTEGER |
|
DBTYPE_I8 |
|
BIGINT |
|
DBTYPE_UI1 |
|
SMALLINT |
|
DBTYPE_UI2 |
|
INTEGER |
|
DBTYPE_UI4 |
|
DECIMAL(10,0) |
|
DBTYPE_UI8 |
|
BIGINT |
|
DBTPYE_R4 |
|
FLOAT |
|
DBTYPE_R8 |
|
FLOAT |
|
DBTYPE_NUMERIC |
|
DECIMAL(p,s)* NUMBER(p,s)* |
|
DBTYPE_DECIMAL |
|
DECIMAL(p,s)* |
|
DBTYPE_CY |
|
DECIMAL(19,4) for Precision > 18 DECIMAL(18,4) for Precision <= 18 |
|
DBTYPE_BSTR |
|
VARCHAR(64000) |
|
DBTYPE_IDISPATCH |
|
BYTE(n) |
|
DBTYPE_ERROR |
|
DECIMAL(10,0) |
|
DBTYPE_BOOL |
|
BYTEINT |
|
DBTYPE_VARIANT |
|
VARCHAR (8000), SMALLINT **** |
|
DBTYPE_IUKNOWN |
|
BYTE(n)** |
|
DBTYPE_GUID |
|
BYTE(n)** |
|
DBTYPE_BYTES |
DBCOLUMNFLAGS_ISFIXEDLENGTH |
BYTE(n)** |
|
DBTYPE_BYTES |
|
VARBYTE(n)** |
|
DBTYPE_STR |
DBCOLUMNFLAGS_ISFIXEDLENGTH |
PERIOD(DATE) |
|
DBTYPE_STR |
DBCOLUMNFLAGS_ISFIXEDLENGTH |
PERIOD[TIME(p)] |
|
DBTYPE_STR |
DBCOLUMNFLAGS_ISFIXEDLENGTH |
PERIOD[TIMESTAMP(p)] |
|
DBTYPE_STR |
DBCOLUMNFLAGS_ISFIXEDLENGTH |
CHAR(n)** |
|
DBTYPE_STR |
|
VARCHAR(n)** |
|
DBTYPE_WSTR |
DBCOLUMNFLAGS_ISFIXEDLENGTH |
CHAR(n)** |
|
DBTYPE_WSTR |
|
VARCHAR(n)** |
|
DBTYPE_UDT |
|
Unsupported |
|
DBTYPE_DATE |
|
TIMESTAMP(p), DATE, & TIME*** |
|
DBTYPE_DBDATE |
|
DATE |
|
DBTYPE_DBTIMESTAMP |
|
TIMESTAMP(p), DATE, & TIME*** |
|
DBTYPE_ARRAY |
|
Unsupported |
|
DBTYPE_BYREF |
|
Indicates the data points to the real data value. For example, DBTYPE_I2 | DBTYPE_BYREF means that the data contains the address of a two‑byte integer. All supported types can be referenced by DBTYPE_BYREF. |
|
DBTYPE_VECTOR |
|
Unsupported |
|
DBTYPE_RESERVED |
|
Unsupported |
|
DBTYPE_NULL |
|
Unsupported |
|
DBTYPE_EMPTY |
|
Unsupported |
|
DBTYPE_DBTIME |
|
TIME |
|
DBTYPE_FILETIME |
|
TIMESTAMP(p), DATE, & FLOAT*** |
|
DBTYPE_PROPVARIANT |
|
Unsupported |
|
DBTYPE_HCHAPTER |
|
DECIMAL(10,0) |
|
DBTYPE_VARNUMERIC |
|
VARCHAR(n)** |
|
*precision (p) and scale (s). **n represents the number of bytes for BYTE(n) and VARBYTE(n), and the number of characters for CHAR(n) and VARCHAR(n). ***All date and time data types are split into a Teradata DATE type for the date portion of the data type, and a Teradata TIME for the time portion [in addition to being available as a Teradata TIMESTAMP(p)]. ****All DBTYPE_VARIANT types are split into a Teradata VARCHAR(8000) type for the Value portion of the VARIANT structure, and a Teradata SMALLINT for the VT portion. |
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