NSImage to blob and blob to NSImage (SQLite, NSData) - objective-c

Question

First of all, I know that I should not use an SQLite database to store image, but I only store favicon of website which are really small.
My problem is that I try to insert those favicon into the database (seems to work), I convert the favicon to NSData with the -tiffrepresentation method of NSimage and then insert it to my database into a blob column:
NSImage *favico = [webview mainFrameIcon];
[appDelegate insertBookmark:[titleField stringValue] url:[urlfield stringValue] data:[favico TIFFRepresentation]]
The SQLite method look like this:
-(void)insertBookmark:(NSString *)title url:(NSString *)url data:(NSData *)data
{
NSData *imagedata = [[NSData alloc]initWithData:data];
sqlite3 *database;
if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) {
NSString *query = [NSString stringWithFormat:#"INSERT INTO Bookmarks (title, url, image) VALUES ('%#', '%#', '%#')",title, url, data];
const char *querychar = [query UTF8String];
sqlite3_stmt *statement;
if (sqlite3_prepare_v2(database, querychar, -1, &statement, NULL) == SQLITE_OK)
{
int row = 3;
sqlite3_bind_blob(statement, row, [imagedata bytes], [imagedata length], NULL);
sqlite3_step(statement);
sqlite3_finalize(statement);
}
else
{
NSLog(#"Error");
}
[databasePath retain];
[databaseName retain];
}
sqlite3_close(database);
[imagedata release];
}
When I look into the database I have value in the image column between <data> (normal ? )
Now when I extract the blob from the database and try to put it in my object I got null in the NSimage:
-(void) readDatabase {
// Setup the database object
sqlite3 *database;
bookmarks = [[NSMutableArray alloc] init];
// Open the database from the users filessytem
if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) {
// Setup the SQL Statement and compile it for faster access
const char *sqlStatement = "SELECT * FROM Bookmarks ORDER BY title ASC";
sqlite3_stmt *compiledStatement;
if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) {
// Loop through the results and add them to the feeds array
while(sqlite3_step(compiledStatement) == SQLITE_ROW) {
// Read the data from the result row
NSString *aTitle = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)];
NSString *aUrl = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 2)];
NSData *data = [[NSData alloc] initWithBytes:sqlite3_column_blob(compiledStatement, 3) length:sqlite3_column_bytes(compiledStatement, 3)];
NSImage *image = [[NSImage alloc]initWithData:data];
bookmarkObject *bookmark = [[bookmarkObject alloc] initWithName:aTitle url:aUrl favico:image];
[bookmarks addObject:bookmark];
[bookmark release];
[data release];
[image release];
}
}
// Release the compiled statement from memory
sqlite3_finalize(compiledStatement);
sqlite3_close(database);
[databasePath retain];
[databaseName retain];
}
}
Thanks in advance

Answer 1

The < and > around your actual data come from NSData. By using %# in your format string and providing data, NSString sends description to data. [NSData description] wraps the content between < and >.
Another issue with your code is, that you seem to mix parameter-less & parameter prepared statements:
Either use stringWithFormat: to create a complete query statement
or use a query like INSERT INTO Bookmarks (title ...) VALUES (? ...) combined with sqlite3_bind_blob
The parameter syntax SQLite supports can be found here:
http://www.sqlite.org/c3ref/bind_blob.html