SQL Server BLOBs vs file links - sql

Im planning to organise picture's storage in SQL Server from public folder. I want to do it as BLOBs.
I read in the internet that if any file from source folder is accidentally removed, it can lead to database failure. Is it correct? Did someone face this problem? Should a source folder be kept with no changes at all?
Thanks very much.

If you are going to store the images as BLOBs, than there is no need for a source file. If you are going to store the actual images in your file system, then yes, you will want some folder to store the actual images and then link to them in your db.
EDIT:
Whether it's images or files. Usually BLOBs are used for images.

Related

How to upload and download media files using GUNDB?

I'm trying to use GUN to create a File sharing platform. I read the tutorial and API but I couldn't find a general way to upload/download a file.
I hear that there is a limitation of 5Mb of localStorage in GUN, if I want to upload a large file, I have to slice it then storage it into GUN. But right now I can't find a way to storage file into GUN.
I read the question from Retric and I know how to store the image into GUN, but can I store the other type of Files such as .zip or .doc File? Is there a general API for file storage?
I wrote a quick little app in 35 lines of HTML to demonstrates file sharing for images, videos, sound, etc.
https://github.com/amark/gun/blob/master/examples/basic/upload.html
I've sent 20MB files thru it, tho yeah, I'm sure there is a better way of splitting it up into 2MB chunks - that is currently not automatic, you'd have to code it.
We'll have a feature in the future that will automatically split up video files. Do you want to help with this?
I think on the download side, all you have to do is make sure you have the whole file (stitch it back together if you do write a splitter upper), and add it to some <a href=" target. Actually, I'm not sure exactly how, but I know browsers support download file attributes for a few years now, where you can create a download link even of a in-memory file... but you'll have to search online for how. Then please write a tutorial and share it with the community!!
I would recommend using IPFS for file storage and GUN to store the links to those files. GUN isn't meant for file storage I believe, primarily user/graph data. Thus the 5 MB limitation.

SQL Database in GitHub

I am building a Java app that uses an SQLite database to hold most of its data. For the end-user, the database would be almost entirely read-only, with very occasional edits. I'll (theoretically) be displaying/distributing it through my GitHub page, so my question is:
What's the best way to load the database into GitHub? (I'm using IntelliJ with DataGrip.)
I'd prefer to be able to update the database when I commit/push, instead of having to overwrite the whole file. The closest question I can find is How to include MySQL database schema on GitHub? but there could potentially be hundreds or thousands of entries, so I can't just rebuild the tables when the user installs the app.
I'm applying for entry-level developer jobs, and this project is going to be my main portfolio piece during job-hunting. I'm trying to make sure it is not only functional but also makes a good impression. Any help is (very) greatly appreciated.
EDIT:
After moving my .db file into the folder connected to GitHub (same level as my src folder) apparently I can now commit/push it with the rest of my files. How do I make sure that the connection from my Java code to the database stays valid once it is loaded onto another user's system? Can I just stick with
connection = DriverManager.getConnection("jdbc:sqlite:mydatabase.db");
or do I need to rework the path?
Upon starting, if your application can't find a corresponding sqlite database file, have it create one. Then do initial load of your tables from either CSV, JSON or XML files.
You can upload these files to Git, as they are text formats.

File permissions on a web server?

I'm new at writing code for websites. The website allows users to upload files, such as profile pictures or other pictures. The files are saved in the unix file system and the URLs to find those images are stored in a MySQL database.
It seems like the only way I can let the user upload files is to give write access to anybody using chmod. Otherwise it complains that it doesn't have write permissions. But they shouldn't be able to write whatever they want or overwrite other users stuff. Similarly, to allow users to see images that they have rightful access to, they need read permissions on the file system. But now that means that anybody with the url to that picture can see the image too, correct? That's not what I want.
Is there a solution to this contradiction? Or am I thinking about the problem incorrectly? Thanks for any help.
You need to manage the permissions in your application and not expose arbitrary parts of your local filesystem directly to the clients. Your application should decide what files someone can see or where to write data. You should not trust data (filenames, etc) from your clients...ideally, store files on disk using systematically generated names and store human-readable names in the database.
SunStar9,
Since you are already using a MySQL database to store the URL of the image on the file system, why not just store the image itself as a BLOB (binary large object)?
This is generally a well-accepted design practice for allowing users to upload binary data to a website.
Are you using PHP, Java, Ruby/Rails, or something other to develop your website? Depending on what you are using, there could be file upload/management plugins or modules that will help you develop what you are trying to do if you are certain you want to use the files ystem for storing the image data.

iPad - how should I distribute offline web content for use by a UIWebView in application?

I'm building an application that needs to download web content for offline viewing on an iPad. At present I'm loading some web content from the web for test purposes and displaying this with a UIWebView. Implementing that was simple enough. Now I need to make some modifications to support offline content. Eventually that offline content would be downloaded in user selectable bundles.
As I see it I have a number of options but I may have missed some:
Pack content in a ZIP (or other archive) file and unpack the content when it is downloaded to the iPad.
Put the content in a SQLite database. This seems to require some 3rd party libs like FMDB.
Use Core Data. From what I understand this supports a number of storage formats including SQLite.
Use the filesystem and download each required file individually. OK, not really a bundle but maybe this is the best option?
Considerations/Questions:
What are the storage limitations and performance limitations for each of these methods? And is there an overall storage limit per iPad app?
If I'm going to have the user navigate through the downloaded content, what option is easier to code up?
It would seem like spinning up a local web server would be one of the most efficient ways to handle the runtime aspects of displaying the content. Are there any open source examples of this which load from a bundle like options 1-3?
The other side of this is the content creation and it seems like zipping up the content (option 1) is the simplest from this angle. The other options would appear to require creation of tools to support the content creator.
If you have the control over the content, I'd recommend a mix of both the first and the third option. If the content is created by you (like levels, etc) then simply store it on the server, download a zip and store it locally. Use CoreData to store an Index about the things you've downloaded, like the path of the folder it's stored in and it's name/origin/etc, but not the raw data. Databases are not thought to hold massive amounts of raw content, rather to hold structured data. And even if they can -- I'd not do so.
For your considerations:
Disk space is the only limit I know on the iPad. However, databases tend to get slower if they grow too large. If you barely scan though the data, use the file system directly -- may prove faster and cheaper.
The index in CoreData could store all relevant data. You will have very easy and very quick access. Opening a content will load it from the file system, which is quick, cheap and doesn't strain the index.
Why would you do so? Redirect your WebView to a file:// URL will have the same effect, won't it?
Should be answered by now.
If you don't have control then use the same as above but download each file separately, as suggested in option four. after unzipping both cases are basically the same.
Please get back if you have questions.
You could create a xml file for each bundle, containing the path to each file in the bundle, place it in a folder common to each bundle. When downloading, download and parse the xml first and download each ressource one by one. This will spare you the overhead of zipping and unzipping the content. Create a folder for each bundle locally and recreate the folder structure of the bundle there. This way the content will work online and offline without changes.
With a little effort, you could even keep track of file versions by including version numbers in the xml file for each ressource, so if your content has been partially updated only the files with changed version numbers have to be downloaded again.

Is storing Image File in database good in desktop application running in network?

I recently came across a problem for image file storage in network.
I have developed a desktop application. It runs in network. It has central database system. Users log in from their own computer in the network and do their job.
Till now the database actions are going fine no problem. Users shares data from same database server.
Now i am being asked to save the user[operator]'s photo too. I am getting confused whether to save it in database as other data or to store in separate file server.
I would like to know which one is better storing images in database or in file server?
EDIT:
The main purpose is to store the account holder's photo and signature and later show it during transaction so that teller can verify the person and signature is correct or not?
See these:
Storing images in database: Yea or nay?
Should I store my images in the database or folders?
Would you store binary data in database or folders?
Store pictures as files or or the database for a web app?
Storing a small number of images: blob or fs?
User Images: Database or filesystem storage?
Since this is a desktop application it's a bit different.
It's really how much data are we talking about here. If you've only got 100 or so users, and it's only profile pictures, I would store it in the DB for a few practical reasons:
No need to manage or worry about a separate file store
You don't need to give shared folder access to each user
No permissions issues
No chance of people messing up your image store
It will be included in your standard DB backup
It will be nicely linked to your data (no absolute vs. relative path issues)
Of course, if you're going to be storing tons of images for thousands of users, I would go with the file system storage.
I think you have to define what you mean with better.
If it is faster my guess you don't want to use a database. You probably just want it plain on a file server.
If you want something like a mini-facebook, where you need a much more dynamic environment, perhaps you are better of storing it a database.
This is more a question than an answer, what do you want to do with the pictures?