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Base de données, Tables, Vues, Index et syntaxe SQL
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>>hi,
>>
>>I always find Xbase commands faster than Sql(statement) commands.
>>
>>
>>Any case where Sql statments are faster ?
>>Also i would like to know best prsctices where to use what ??
>>
>>
>>TIA
>>suhashegde
>
>Post a example where XBASE is faster.
Hi,
I have this problem.
the table is
create table bhav_data.dbf free ;
(symbol c(20),series c(20),open f(20,2),high f(20,2),low f(20,2),close f(20,2),;
last f(20,2),prevclose f(20,2),tottrdqty f(20,2),tottrdval f(20,2),timestamp c(20),date d,delqty i,delpercent f(20,2))
contains 266928 records
size 65,951 kb
test machine AMD k6 500mhz , 256 mb ram , 40Gb hd 5600rpm
It is index like
Index on timestamp tag t1
index on timestamp tag tq unique additive
cdx file size is 1,237 kb
when i use this sql
tt = seconds()
select dist timestamp from bhav_data into cursor test nofilter
?tt-seconds()
it runs at 0.819 sec returning 341 recs
and when i do
m.t1 = seconds()
use bhav_data in 0 order tq
create cursor test(timestamp c(20))
index on t1 tag t1
select bhav_data
scan for !seek(timestamp,'test','t1')
insert into test(timestamp) values(bhav_data.timestamp)
endscan
select test
locate && to set the record pointer to 1 as to compare case of sql
delete tag t1
?seconds() - m.t1
it runs in 0.288 sec returning 341 rec
Kindly tell me how can i still optmise the sql please ???
suhashegde
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