Question

The code below partially works. Its supposed to return all the tables in the sqlite_master table and then delete them.

 NSString *sql = [NSString stringWithFormat:@"SELECT name FROM sqlite_master WHERE type='table';"];

        sqlite3_stmt *statement = [database prepare:sql];
        if(statement != nil)
        {
            while(sqlite3_step(statement) == SQLITE_ROW)
            {
                NSString* currentTable = [NSString stringWithUTF8String:(char *)sqlite3_column_text(statement, 0)];
                if ([currentTable rangeOfString:@"sqlite"].location == NSNotFound && 
                    [currentTable rangeOfString:@"Setting"].location == NSNotFound)
                {
                    NSLog(@"current table: %@", currentTable);
                    [database deleteTable: currentTable];
                }
            }
            sqlite3_finalize(statement);
        }

However, after calling [database deleteTable: currentTable]; the tables are not being deleted.

delete table is just an sqlite3_exec which accepts the sql: [NSString stringWithFormat:@"DROP TABLE IF EXISTS '%@'", tableName]

Why is this? Is it because whilst i’m in the loop the database is in use? Would I be better putting the results in an array and than looping through and deleting tables that way? No exceptions are thrown/crashes etc and the exec is being executed.

Answer 1

Try finalizing using sqlite3_finalize after every delete.

Hope this helps you.