Hi

EDB 2.02

Can i have a list of UNIQUE value of field ,using the index ?

like this :

Select distinct MYFIELD1 from MyTable

this is a HUGE file. i have a index for MYFIELD1



DbIsam4 do query but don't work with index ( very slow )

Mauro,

<< Can i have a list of UNIQUE value of field ,using the index ?

like this :

Select distinct MYFIELD1 from MyTable

this is a HUGE file. i have a index for MYFIELD1 >>

With EDB you need to have a PRIMARY constraint on the column in question in
order to EDB to be able to optimize such a query and use the constraint's
internal index.   A UNIQUE constraint is not enough, because it allows for
multiple NULL values in the constraint's internal index.

--
Tim Young
Elevate Software
www.elevatesoft.com

> With EDB you need to have a PRIMARY constraint on the column in question
> in
> order to EDB to be able to optimize such a query and use the constraint's
> internal index.   A UNIQUE constraint is not enough, because it allows for
> multiple NULL values in the constraint's internal index.

then.. don't support it

in PRIMARY constraint ,  of course.... but is useless here. ( is 1:1
already )

Mauro,

<< then.. don't support it >>

Don't support *what* ?

--
Tim Young
Elevate Software
www.elevatesoft.com

> Don't support *what* ?

i have this table

FIELD1
1
1
2
2
3
4
4
4
5
10
10

i need extract : 1-2-3-4-5-10 in fast mode , having a index for FIELD1

With EDB 2 , i can do it ?

Mauro,

<< i have this table >>

I already answered your question regarding this.  EDB can only use a PRIMARY
constraint's internal index in order to optimize a single-column DISTINCT.

--
Tim Young
Elevate Software
www.elevatesoft.com