將UIImage保存爲Blob SQLite

我有以下代碼將信息推送到數據庫。它提供了一個成功的插入，但「畫布」列（包含圖像斑點的列）爲NULL。在我已經在StackOverflow上看過其他答案之後，我已經使用了sqlite3_prepare_v2和sqlite3_bind_blob。將UIImage保存爲Blob SQLite

-(void) sendMoment: (Album *) alb moment:(Moment *) m 
{ 
    @try { 
     NSFileManager *fileMgr = [NSFileManager defaultManager]; 

     // First, test for existence of writable file: 
     NSError *error; 
     NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
     NSString *documentsDirectory = [paths objectAtIndex:0]; 
     NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:@"pictures.sqlite"]; 

     BOOL success = [fileMgr fileExistsAtPath:writableDBPath]; 
     if (!success){ 
      // The writable database does not exist, so copy the default to the appropriate location. 
      NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"pictures.sqlite"]; 
      success = [fileMgr copyItemAtPath:defaultDBPath toPath:writableDBPath error:&error]; 
      if (!success) { 
       NSAssert1(0, @"Failed to create writable database file with message '%@'.", [error localizedDescription]); 
      } 
     } 

     NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init]; 
     [dateFormat setDateFormat:@"yyy-MM-dd HH:mm:ss"]; 
     NSString *dateString = [dateFormat stringFromDate: m.timestamp]; 

     //add passed-in moment to the given album 
     sqlite3_stmt *sqlStatement; 
     NSData *imageData = UIImageJPEGRepresentation([m.moment firstObject], 1.0); 


     NSString *deleteSQL = [NSString stringWithFormat:@"DELETE FROM MomentTbl WHERE user = \"t-amkruz\""]; 

     NSString *momentInsertSQL = [NSString stringWithFormat:@"INSERT INTO MomentTbl (momentID, albumID, title, timestamp, author, latitude, longitude, canvas) VALUES (NULL, %d, '%@', '%@', '%@', '%@', '%@', ?)", alb.ID, alb.title, dateString, @"user", m.latitude, m.longitude]; 
     const char *query_stmt = [momentInsertSQL UTF8String]; 
     const char *dbPath = [writableDBPath UTF8String]; 

     int result = sqlite3_open(dbPath, &db); 

     if (SQLITE_OK == result) { 
      char *errInfo = nil; 

      sqlite3_prepare_v2(db, query_stmt, -1, &sqlStatement, NULL); 

      sqlite3_bind_blob(sqlStatement, 1, [imageData bytes], [imageData length], SQLITE_TRANSIENT); 

      result = sqlite3_exec(db, query_stmt, nil, nil, &errInfo); 
      if (SQLITE_OK == result) { 
       NSLog(@"Sucessful insert"); 
      } else { 
       NSLog(@"Insert failed"); 
      } 
      sqlite3_close(db); 
     } 

     else { 
      NSLog(@"Could not open database"); 
     } 

    } 
    @catch (NSException *exception) { 
     NSLog(@"An exception occured: %@", [exception reason]); 
    } 
}

同樣，我唯一有問題的部分是最後一列;正確插入每個其他列的值。我已驗證imageData不是nil。當我使用NSLog檢查它們時，prepare_v2語句和bind_blob語句都返回0。我真的很感激幫助！

來源

2014-07-15 Amyga17

原來，我需要更換exec語句（以及隨後的if語句）以下各項：

if(sqlite3_step(sqlStatement) == SQLITE_OK){ 
    NSLog(@"Sucessful insert"); 
} 
else { 
    NSLog(@"Insert failed"); 
}

希望這可以幫助其他人。

來源

2014-07-15 21:11:18 Amyga17

將UIImage保存爲Blob SQLite

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