[fpc-pascal] How to clear the value of a field in a table using parameters?
Michael Van Canneyt
michael at freepascal.org
Fri Aug 30 08:42:25 CEST 2013
On Fri, 30 Aug 2013, Sven Barth wrote:
> Am 29.08.2013 23:04 schrieb "Michael Van Canneyt" <michael at freepascal.org>:
> > On Thu, 29 Aug 2013, silvioprog wrote:
> >> Other interesting feature is the property EmptyAsNull:
> >> http://docwiki.embarcadero.com/VCL/XE/en/IBCustomDataSet.TIBStringField.EmptyAsNull
> >> It tests if field (ftString) is empty (f = ''), if yes, it set the field value to null (f.Clear).
> > Apparently a IBX specific extension.
> > I don't see the value of this. empty and null are different things.
> Not everywhere. In Oracle empty strings are Null (which is why we have special code for this situation in our business
That's a deviation from the standard. NULL means "we don't know", empty means "we know it is empty"
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