use transactions, speeds up a lot Op maandag 20 juni 2005 11:35, schreef Yuriy: > Hello sqlite-users, > > Sqlite low level and Speed. > > Sorry for my bad English. > > I try use Sqlite for Operation FAST grouping strings (delete > duplicates) > > I have input array of strings > > String1 > String2 > String3 > String1 > String2 > ……… > StringN > > > Need delete dublicates. > > Output database > String1 > String2 > String3 > …….. > StringN > > 1. Example of the decision > > CREATE TABLE testtable (val text) > CREATE INDEX index_val ON [testtable]([val]); > PRAGMA synchronous = OFF; > > for i:=1 to 10000000 do > begin > select * from testable where val=StringN > if val NOT Exist insert into testtable > end > > Very Slow. > > 2. Example of the decision > > > CREATE TABLE testtable (val text,hashval integer) > CREATE INDEX index_hashval ON [testtable]([ hashval]); > PRAGMA synchronous = OFF; > > for i:=1 to 10000000 do > begin > select * from testable where hashval=hash(StringN)and(val= StringN) > if val NOT Exist insert into testtable > end > > Very Slow. > > > 3. Example of the decision > > I find good example for SQLite Low level functions SQlite VS BDB. > > http://rganesan.blogspot.com/ > > But this example use such functions as > > sqlite3BtreeOpen > sqlite3BtreeInsert > sqlite3BtreeCursor > > I Use Windows and Delphi. In the SQlite3.dll no import this functions. > > Please Help me. May be need recompile sql I Have Visual C++ and C++Builder > If need recompile as make it is on Windows Platform? > > May be present other decision this problem? Need more speed for grouping > big arrays of strings > > Thanks you.
-- Met vriendelijke groet Bert Verhees ROSA Software
