I don't fully understand sqlite3_finalize

Question

I don't fully understand sqlite3_finalize. My initialy code.

while (j < Autors.count)
{
 if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) 
 {
    sqlite3_bind_int(compiledStatement,  1, ((AuthorSettings *)[Autors objectAtIndex:j]).authorId);
    if(sqlite3_step(compiledStatement) != SQLITE_DONE) 
    {    
        NSLog(@"sqlite3_step error %s", sqlite3_errmsg(database));
        sqlite3_busy_timeout(database, 5);
    } 
    else
    {    
        if(sqlite3_prepare_v2(database, sqlStatement_1, -1, &compiledStatement, NULL) == SQLITE_OK) 
        {
            sqlite3_bind_int(compiledStatement,  1, bookId);
            if(sqlite3_step(compiledStatement) != SQLITE_DONE) 
            {    
                NSLog(@"sqlite3_step error %s", sqlite3_errmsg(database));
                sqlite3_busy_timeout(database, 5);
            }    
            else  j++;    
        } 
        else NSLog(@"sqlite3_prepare_v2 error %s", sqlite3_errmsg(database));
    }    
 }
}
sqlite3_finalize(compiledStatement);

I added sqlite3_finalize functions. Please check me.

while (j < Autors.count)
 {
 sqlite3_finalize(compiledStatement); //**added
 if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) 
 {
    sqlite3_bind_int(compiledStatement,  1, ((AuthorSettings *)[Autors objectAtIndex:j]).authorId);
    if(sqlite3_step(compiledStatement) != SQLITE_DONE) 
    {    
        NSLog(@"sqlite3_step error %s", sqlite3_errmsg(database));
        sqlite3_busy_timeout(database, 5);
    } 
    else
    {   
        sqlite3_finalize(compiledStatement); //**added
        if(sqlite3_prepare_v2(database, sqlStatement_1, -1, &compiledStatement, NULL) == SQLITE_OK) 
        {
            sqlite3_bind_int(compiledStatement,  1, bookId);
            if(sqlite3_step(compiledStatement) != SQLITE_DONE) 
            {    
                NSLog(@"sqlite3_step error %s", sqlite3_errmsg(database));
                sqlite3_busy_timeout(database, 5);
            }    
            else  j++;    
        } 
        else NSLog(@"sqlite3_prepare_v2 error %s", sqlite3_errmsg(database));
    }    
 }
}
sqlite3_finalize(compiledStatement);

Answer 1

sqlite3_finalize is the opposite of sqlite3_prepare_v2. So your code should look something like this:

sqlite3_prepare_v2(...);
while () {
  sqlite3_reset(...);
  sqlite3_bind_int(...);
  sqlite3_step(...);
}
sqlite3_finalize(...);

You don't want to prepare you statements more than necessary.