iphone - 如何从 iPhone 数据库中仅检索 3imagepaths 或 id

Question

我是手机编程的新手。我将图像路径和音频路径存储在数据库中。现在我想从数据库中检索图像路径，我得到了所有图像路径，但我只想检索剩下的 3 个图像路径，我想在其他地方使用。任何人都可以告诉我如何仅检索 3 个图像路径表单数据库下面的代码用于从数据库检索图像路径

     NSString *docsDir;
                NSArray *dirPaths;

                // Get the documents directory
                dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

                docsDir = [dirPaths objectAtIndex:0];
                arrayy=[[NSMutableArray alloc]init];
                arrayy2=[[NSMutableArray alloc]init];
                arrayy1=[[NSMutableArray alloc]init];
                // array2=[[NSMutableArray alloc]init];


                // Build the path to the database file
                databasePath =  [docsDir stringByAppendingPathComponent: @"Taukydaataaa.db"];
                //  NSLog(@"%@",databasePath);
                NSFileManager *fn=[NSFileManager defaultManager];
                NSError *error;
                BOOL success=[fn fileExistsAtPath:databasePath];

                if(!success) {

                    NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"Taukydaataaa.db"];
                    success = [fn copyItemAtPath:defaultDBPath toPath:databasePath error:&error];
                }


                const char *dbpath = [databasePath UTF8String];

                sqlite3_stmt    *statement;

                if (sqlite3_open(dbpath, &contactDB) == SQLITE_OK)
                {

  NSString *querySQL = [NSString stringWithFormat: @" select t.imagepath,t.audiopath,t.id from blauky b,taukyblauky tb,tauky t where tb.blaukyid=b.id and tb.taukyid=t.id and tb.blaukyid=1"];

                    const char *query_stmt = [querySQL UTF8String];


                    if (sqlite3_prepare_v2(contactDB, query_stmt, -1, &statement, NULL) == SQLITE_OK)
                    {

                        while(sqlite3_step(statement) == SQLITE_ROW)
                        {

                             email_idField = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement,2)];

                          email_idField1 = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement,1)];
                            email_idField2 = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement,0)];


                            //       NSString *email_idField2 = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement,2)];
                            NSLog(@"ASlma");
                            NSLog(@"%@",email_idField);

                            NSLog(@"%@",email_idField1);
                            NSLog(@"%@",email_idField2);
                            [arrayy addObject:email_idField];
                            [arrayy1 addObject:email_idField1];
                            [arrayy2 addObject:email_idField2];
                            NSLog(@"%@",arrayy);
                            NSLog(@"%@",arrayy1);
                            NSLog(@"%@",arrayy2);
                            NSLog(@"Iam here");

                            }
                        }
                    }
                }

谢谢阿斯拉姆

Answer 1

您可以将 LIMIT 3 添加到您的查询中。