sqlite数据库插入和读取图片数据 (for ios)

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：

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:

// 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:

// 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;

}