OLE DB Programmer's Reference |
OLE DB defines a standard set of data type indicators for the most commonly used data types. Providers use these data type indicators to tell consumers what data types they support. Each provider maps its own underlying data types to these data type indicators and advertises its support for them through the PROVIDER_TYPES schema rowset. The underlying data types used by the provider are unimportant to the consumer. What is important is that the provider guarantees that it can always safely transfer data in the type represented by the indicator it advertises for a column or parameter. For examples of how various providers might map underlying data types to OLE DB data types, see the following sections.
Providers are not required to support all of the OLE DB data types listed in "Type Indicators" in Appendix A: Data Types, nor are they required to support all possible conversions among them. For information about what conversions all providers are required to support, see "Data Type Conversion," later in this chapter.
Although OLE DB attempts to provide a unified type system, it is subject to the following limitations:
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