I was speaking from a pure theory perspective, not from an Access-specific one.

OLE objects aren't "data" per se; they're, well, OBJECTS. And memo fields
cannot be used as indexes or searched on, so as a key they'd be impossible to
use. In the "old-timey world" one needed to keep one's keys as short as
possible while being meaningful. A key-length over about 15 characters almost
guaranteed terrible application performance. But that was then....

"Jamie Collins" wrote:

On Dec 4, 10:53 pm, Dennis wrote:
ANY data can be used as a Primary Key AS LONG AS you are 100% sure of no
duplication and/or have code in place to prevent such an occurrance.

IIRC a column of type OLEOBJECT cannot be PRIMARY KEY.

Perhaps you meant to say "as long as the engine can be 100% sure of no
duplication"? While I can be sure that I am putting unique values into
a MEMO column, the engine only considers the first 255 characters when
checking a PRIMARY KEY constraint. Also I'd be vary wary of
approximate numeric types (e.g. REAL and FLOAT).

Jamie.

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