Performance reading field().value

[Ruslan Zasukhin]

On 4/11/09 7:24 PM, "Thomas Flemming" <tf at ttqv.com> wrote:

Hi Thomas,
 
> I'm new to Valentina and currently busy to find out, if I can use it for a
> geographical project which contains some mio objects.
> 
> I set up my first database with 500.000 records.
> Then I like to query some records (I'm using VB.NET):
> 
> Dim mCursor As IVCursor
> mCursor = mDB.SqlSelect("select * from myobjects where a>8 and b>3 and c>6")
> 
> this gives me for example hundred records in 0.05sec, very fast :-)
> 
> Then I like to get the records.
> So I loop through the cursor:
> 
> Dim mTbl As IVTable = mDB.Table("myobjects ")
> 
> For i = 1 to mCursor.count
>     a = mTbl.Field(1).value
>     b = mTbl.Field(2).value
>     c = mTbl.Field(3).value
>     mCursor.NextRecord() 
> Next
> 
> And here is the problem, because this takes some seconds for only 100 records
> in the cursor.
> It seems to be the access to a specific Field, which is so slow. Just looping
> through the cursor:
> 
> For i = 1 to mCursor.count
>     mCursor.NextRecord() 
> Next
> 
> is still very fast.
> 
> Where am I wrong? How can I access the values of a record fast?

I have not checked sources
Just ideas from head.

    Field.Value     -- this is work with VARIANT.

Try to use type-specific way.
You know types of fields, let it be Ulong.

So 

 For i = 1 to mCursor.count
     a = mTbl.ULongField(1).value
     b = mTbl.ULongField(2).value
     c = mTbl.ULongField(3).value
     mCursor.NextRecord()
 Next





-- 
Best regards,

Ruslan Zasukhin
VP Engineering and New Technology
Paradigma Software, Inc

Valentina - Joining Worlds of Information
http://www.paradigmasoft.com

[I feel the need: the need for speed]