How to use sqlite3_column_blob with NSData - iphone

Question

How to use sqlite3_column_blob with NSData what parameter I need to pass
In my iPhone App I want to retrive image stored in NSData format in sqlite database in BLOB datatype
for retriving it
//select query
NSString *selectQuery = [NSString stringWithFormat:#"select image_column from tbl_image where id=1"];
NSArray *arraySelect = [database executeQuery:selectQuery];
//displaying image
NSData *imageData = [[arraySelect objectAtIndex:0] valueForKey:#"image_column"];
self.img3=[UIImage imageWithData:imageData];
imageView.image=img3;
from above code I am not able to display image
so please help and suggest
thanks

Answer 1

sqlite *database;
sqlite3_stmt *Stmt;
sqlite3_open([[self getDBPath] UTF8String],&database)
- (NSString *) getDBPath
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask, YES);
NSString *documentsDir = [paths objectAtIndex:0];
return [documentsDir stringByAppendingPathComponent:#"XXX.sqlite"];
}
NSData*thumbnailData;
//Inserting Thumbnail Data
NSString *lSQL = [NSString stringWithFormat:#"insert into Table(Thumbnail1) values(?)"];
if(sqlite3_prepare_v2(database, [lSQL UTF8String], -1, &Stmt, NULL) == SQLITE_OK)
{
sqlite3_bind_blob(Stmt, 1,[thumbnailData bytes], [thumbnailData length], NULL);
sqlite3_step(Stmt);
sqlite3_reset(Stmt);
if(Stmt)
sqlite3_finalize(Stmt);
}
//Fetching Thumbnail Data
NSString *lSQL = [NSString stringWithFormat:#"select Thumbnail1 from table"];
if(sqlite3_prepare_v2(database, [lSQL UTF8String], -1, &Stmt, NULL) == SQLITE_OK)
{
while(sqlite3_step(Stmt) == SQLITE_ROW)
{
NSString *myColNameNSString = [NSString stringWithFormat:#"%s", sqlite3_column_name(Stmt)];
if ([myColNameNSString isEqualToString:#"Thumbnail1"])
{
thumbnailData = [[NSData alloc] initWithBytes:sqlite3_column_blob(Stmt) length:sqlite3_column_bytes(Stmt)];
}
}
}

Answer 2

Hey, I don't what are your project requirements. I would not use BLOB unless it's required to.
reason is you are storing image file into sqlite, everytime you have to use the file you have access the database, process the file and use. which will be fairly easy and simple in terms of number of threads you are running if you use images directly form the disk. give a thought about it. Good Luck