| Subject | Re: [firebird-support] what is better : null or empty string in index ? |
|---|---|
| Author | Ann W. Harrison |
| Post date | 2009-12-08T19:08:45Z |
svanderclock wrote:
rid of duplicates - null, empty, or full. NULL has some advantages
in terms of index ordering - they can be first, last, high, or low.
But I would use NULL only when the value is not known, and empty
strings when the value is known not to exist.
Good luck,
Ann
>In terms of storage, it doesn't matter. Prefix compression gets
> in an index (where around 20% of values are null), what is better, to put null or an empty string ? or doeasn't matter?
>
rid of duplicates - null, empty, or full. NULL has some advantages
in terms of index ordering - they can be first, last, high, or low.
But I would use NULL only when the value is not known, and empty
strings when the value is known not to exist.
Good luck,
Ann