Ich habe diese vorbereiteten Aussagen mit gehörtSQLite sollte die Leistung verbessern. Ich habe einen Code geschrieben, um dies zu testen, und dabei keinen Unterschied in der Leistung festgestellt. Also dachte ich, mein Code sei vielleicht falsch. Bitte lassen Sie mich wissen, wenn Sie Fehler in der Vorgehensweise sehen ...

[self testPrep:NO dbConn:dbConn];
[self testPrep:YES dbConn:dbConn];

reuse=0
recs=2000
2009-11-09 10:39:18 -0800
processing...
2009-11-09 10:39:32 -0800

reuse=1
recs=2000
2009-11-09 10:39:32 -0800
processing...
2009-11-09 10:39:46 -0800

-(void)testPrep:(BOOL)reuse dbConn:(sqlite3*)dbConn{
    int recs = 2000;
    NSString *sql;
    sqlite3_stmt *stmt;

    sql = @"DROP TABLE test";
    sqlite3_exec(dbConn, [sql UTF8String],NULL,NULL,NULL);

    sql = @"CREATE TABLE test (id INT,field1 INT, field2 INT,field3 INT,field4 INT,field5 INT,field6 INT,field7 INT,field8 INT,field9 INT,field10 INT)";
    sqlite3_exec(dbConn, [sql UTF8String],NULL,NULL,NULL);

    for(int i=0;i<recs;i++){
        sql = @"INSERT INTO test (id,field1,field2,field3,field4,field5,field6,field7,field8,field9,field10) VALUES (%d,1,2,3,4,5,6,7,8,9,10)";
        sqlite3_exec(dbConn, [sql UTF8String],NULL,NULL,NULL);
    }

    sql = @"BEGIN";
    sqlite3_exec(dbConn, [sql UTF8String],NULL,NULL,NULL);

    if (reuse){
        sql = @"select * from test where field1=?1 and field2=?2 and field3=?3 and field4=?4 and field5=?5 and field6=?6 and field6=?6 and field8=?8 and field9=?9 and field10=?10 and id=?11";
        sqlite3_prepare_v2(dbConn, [sql UTF8String], -1, &stmt, NULL);
    }

    NSLog(@"reuse=%d",reuse);
    NSLog(@"recs=%d",recs);
    NSDate *before = [NSDate date];
    NSLog([before description]);
    NSLog(@"processing...");
    for(int i=0;i<recs;i++){
        if (!reuse){
            sql = @"select * from test where field1=?1 and field2=?2 and field3=?3 and field4=?4 and field5=?5 and field6=?6 and field6=?6 and field8=?8 and field9=?9 and field10=?10 and id=?11";
            sqlite3_prepare_v2(dbConn, [sql UTF8String], -1, &stmt, NULL);
        }
        sqlite3_bind_int(stmt, 1, 1);
        sqlite3_bind_int(stmt, 2, 2);
        sqlite3_bind_int(stmt, 3, 3);
        sqlite3_bind_int(stmt, 4, 4);
        sqlite3_bind_int(stmt, 5, 5);
        sqlite3_bind_int(stmt, 6, 6);
        sqlite3_bind_int(stmt, 7, 7);
        sqlite3_bind_int(stmt, 8, 8);
        sqlite3_bind_int(stmt, 9, 9);
        sqlite3_bind_int(stmt, 10, 10);
        sqlite3_bind_int(stmt, 11, i);

        while(sqlite3_step(stmt) == SQLITE_ROW) {
        }
        sqlite3_reset(stmt);
    }

    sql = @"BEGIN";
    sqlite3_exec(dbConn, [sql UTF8String],NULL,NULL,NULL);

    NSDate *after = [NSDate date];
    NSLog([after description]);
}