When creating tables by using ITableDefinition::CreateTable, the SQLOLEDB consumer can specify SQL Server data types in the pwszTypeName member of the DBCOLUMNDESC array passed. If the consumer specifies a column’s data type by name, then OLE DB type mapping, represented by the wType member of the DBCOLUMNDESC structure, is ignored.
When specifying new column data types with OLE DB types, that is, when using the DBCOLUMNDESC structure wType member, SQLOLEDB maps OLE DB types as follows.
OLE DB data type |
SQL Server data type | Additional information |
| DBTYPE_BOOL | bit | |
| DBTYPE_BYTES | binary, varbinary or image | SQLOLEDB inspects the ulColumnSize member of the DBCOLUMNDESC structure. Based on the value, and the version of the SQL Server, SQLOLEDB maps the type to image.
If the value of ulColumnSize is smaller than the maximum length of a binary data type column, then SQLOLEDB inspects the DBCOLUMNDESC rgPropertySets member. If the DBPROP_COL_ |
| DBTYPE_CY | money | |
| DBTYPE_ DBTIMESTAMP |
datetime | |
| DBTYPE_GUID | uniqueidentifier | |
| DBTYPE_I2 | smallint | |
| DBTYPE_I4 | int | |
| DBTYPE_NUMERIC | numeric | SQLOLEDB inspects the DBCOLUMDESC bPrecision and bScale members to determine precision and scale for the numeric column. |
| DBTYPE_R4 | real | |
| DBTYPE_R8 | float | |
| DBTYPE_STR | char, varchar or text | SQLOLEDB inspects the ulColumnSize member of the DBCOLUMNDESC structure. Based on the value and the version of the SQL Server, SQLOLEDB maps the type to text.
If the value of ulColumnSize is smaller than the maximum length of a multibyte character data type column, then SQLOLEDB inspects the DBCOLUMNDESC rgPropertySets member. If the DBPROP_COL_FIXEDLENGTH is VARIANT_TRUE, SQLOLEDB maps the type to char. If the value of the property is VARIANT_ |
| DBTYPE_UI1 | TINYINT |
Note When creating a new table, SQLOLEDB maps only the OLE DB data type enumeration values specified in the table above. Attempting to create a table with a column of any other OLE DB type generates an error.