在Sqlite数据库插入和读取图片数据-mysql教程-PHP中文网

在Sqlite数据库插入和读取图片数据

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发布： 2016-06-07 15:42:01

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在iOS下用sqlite数据库存储图片，先把你的图片转换成 NSData 形式，然后在数据库添加一行 blob 数据假定数据库中存在表 test_table(name,image), 下面代码将图片文件test.png的二进制数据写到sqlite数据库：例1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

在iOS下用sqlite数据库存储图片，先把你的图片转换成 NSData 形式，然后在数据库添加一行 blob 数据

假定数据库中存在表 test_table(name,image), 下面代码将图片文件test.png的二进制数据写到sqlite数据库：

例1

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CHAR *name = "test";
NSString * nameString = [NSString stringWithCString:name encoding:NSUTF8StringEncoding];
NSString * filePath = [[NSBundle mainBundle] pathForResource:nameString ofType:@"png"];
IF ([[NSFileManager defaultManager] fileExistsAtPath:filePath])
{
NSData * imgData = UIImagePNGRepresentation([UIImage imageWithContentsOfFile:filePath]);
const CHAR * sequel = "insert into test_table(name,image) values(?,?)";

sqlite3_stmt * UPDATE;
  IF (sqlite3_prepare_v2(DATABASE, sequel, -1, &UPDATE, NULL) == SQLITE_OK)
  {
sqlite3_bind_text(UPDATE, 1, name, -1, NULL);
sqlite3_bind_blob(UPDATE, 2, [imgData bytes], [imgData LENGTH], NULL);
  IF( sqlite3_step(UPDATE) == SQLITE_DONE)
  {
NSLog(@"已经写入数据");
  }
sqlite3_finalize(UPDATE);
  }
}
ELSE
{
NSLog(@"文件不存在");
}

下面代码从数据库中读取图片二进制数据，然后显示图片：
const CHAR * sequel = "select image from test_table where name=?";
sqlite3_stmt * getimg;
IF (sqlite3_prepare_v2(DATABASE, sequel, -1, &getimg, NULL) == SQLITE_OK)
{
  CHAR *name = "test";
sqlite3_bind_text(UPDATE, 1, name, -1, NULL);
  IF(sqlite3_step(getimg)  == SQLITE_ROW)
  {
  INT bytes = sqlite3_column_bytes(getimg, 0);
Byte * VALUE = (Byte*)sqlite3_column_blob(getimg, 1);
  IF (bytes !=0 && VALUE != NULL)
  {
NSData * DATA = [NSData dataWithBytes:VALUE LENGTH:bytes];
UIImage * img = [UIImage imageWithData:DATA];
UIImageView * aview =[[UIImageView alloc] initWithFrame:
                                    CGRectMake(0.0, 0.0, IMAGE_WIDTH, IMAGE_HEIGHT)];
aview.image = img;
  [SELF.VIEW addSubview:aview];
  [aview release];
}
}
sqlite3_finalize(getimg);
}

例2:存储图片

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// Save Small Image Data by given main url
- (void) SaveImagesToSql: (NSData*) imgData :(NSString*) mainUrl
{
NSLog( @"\n*****Save image to SQLite*****\n" );

  const char* sqliteQuery = "INSERT INTO IMAGES (URL, IMAGE) VALUES (?, ?)";
sqlite3_stmt* statement;

  if( sqlite3_prepare_v2(articlesDB, sqliteQuery, -1, &statement, NULL) == SQLITE_OK )
  {
sqlite3_bind_text(statement, 1, [mainUrl UTF8String], -1, SQLITE_TRANSIENT);
sqlite3_bind_blob(statement, 2, [imgData bytes], [imgData length], SQLITE_TRANSIENT);
sqlite3_step(statement);
  }
  else NSLog( @"SaveBody: Failed from sqlite3_prepare_v2. Error is: %s", sqlite3_errmsg(articlesDB) );

  // Finalize and close database.
sqlite3_finalize(statement);
}

读取图片:

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// Load images from data base with given image url
- (NSData*) LoadImagesFromSql: (NSString*) imageLink
{
  NSData* data = nil;
  NSString* sqliteQuery = [NSString stringWithFormat:@"SELECT IMAGE FROM IMAGES WHERE URL = '%@'", imageLink];
sqlite3_stmt* statement;

  if( sqlite3_prepare_v2(articlesDB, [sqliteQuery UTF8String], -1, &statement, NULL) == SQLITE_OK )
  {
  if( sqlite3_step(statement) == SQLITE_ROW )
  {
  int length = sqlite3_column_bytes(statement, 0);
data   = [NSData dataWithBytes:sqlite3_column_blob(statement, 0) length:length];
  }
  }

  // Finalize and close database.
sqlite3_finalize(statement);

  return data;

}