I am trying to reverse engineering to a database file that an android application generates. It gives me a SQLite file in .db extension. I tried pass it through SQLite Browser and it gets me the tables, but no relationships also every table givesme "id" for primary key. Any help or suggestions on how to approach this would be great, thanks!
After extensive search, I found that you can do it without running a server using DBVisualizer.
After you install DBVisualizer, import your database, then expand the database connection which is on the left under Connections, expand schema then double click Tables. Switch to References tab in the pane on the right and you'll have your diagram.
I have also found about SchemaCrawler which is free and open source unlike DBVisualizer and also doesn't require running a server, but have yet to get it to work. You can follow this guide if you wish to use this instead.
Example of ER diagram generated by DBVisualizer
The quickest way to do this is by using the SchemaCrawler web application. If you need to keep your database private, you can use the approach suggested by #freshpasta
In the MySQL workbench select Database option from the menus available on the top of the screen,there you will get reverse engineer option. Click on it then select your server and database on which you want to create ER diagram and click next.
A bit late but if you got IntelliJ IDE product you can connect to your "Database" and generate a diagram for it.
https://www.jetbrains.com/help/pycharm/creating-diagrams.html
Note: IntelliJ is paid tool,so you may need a paid version for this trick
Or just enable free trial till you do this task.
References
https://www.jetbrains.com/products/compare/?product=idea&product=idea-ce
https://www.jetbrains.com/datagrip/features/
Related
I'm really new to programming apps - so this question might sound a bit strange:
I'm trying to program an app in android studio, where people can upload different things (basically strings and links put together in some kind of "package") and other peoble can then decide what "packages" they want to add inside their app. However after downloading, this data should be stored on their device and not just in the memory of the phone so that they can use it after restarting the app (and also if theres no internet connection). Do you have any idea what would be the best way to store this data both on the phone and in a database and how to synchronize the data on the phone with the selected data from the database. I really dont want to know how to do this exactly but would rather like some basic ideas and maybe you could tell me what kinds of stuff i should learn in order to succeed and what kind of database would be best here (firebase, MYSQL,..)?
Thanks a lot,
Andi
First of all you should decide what DB you are going to use.
In my opinion all RDBMs are good, but using Sqlite in order to achieve best performance on android devices is a good idea.
In your case you need server-side DB and application too.
(Depend on the scenario and framework you use can be different (sql,mysql,PostgreSQL,oracle,...)).
About how to sync local database with server-side you can download new DB from server and replace it with previous one, if you need previous user data you can have 2 different table and update one by downloading it from server, and save id or any identical row from specific package that already saved by user.
These are some question has been already answered in Stackoverflow
java - How to update table in sqlite?
java - SQLite in Android How to update a specific row
Create SQLite database in android
If you are talking about local databases. Go for Realm or look up a good ORM on github (Object relational mapping, you dont have to write SQL queries explicitly) .
I would suggest Realm which is very fast and user friendly.
I see a sqllite database in another application, why can't I just just drag and drop from that application to mine in the eclipse environment? that way I can use data already in that database?
Android doesn't do too well with using an sqlite database file directly. Generally the way to go around it is to package an sqlite database as a resource and on first create of the app to load that resource and then connect to it and then copy all the data out of it. The downside of this is you are essentially doubling all your data.
If you are the publisher of the other app then you can list the database as a shared database to share between your apps.
Share SQLite database between 2 android apps?
Noone has written an Eclipse plugin that does that. You can write one if you feel it is both useful and worth your time.
I'm starting to build a new Android application which will help me to manage material movements in a warehouse. I would like to use use a database for the following applications:
A table that will be managed from a server (my PC probably) to add or delete new users.
Also, there must be another table that will be managed by users. This table will be used to add or delete materials from the warehouse.
I'm not sure what kind of database to use. I have some knowledge of using MySQL Workbench to create and manage databases. However, I've read the SQLite is better for Android applications. Can you please help me to choose which one will be the best for my application?
Thanks
If the databases run on the android device (which I guess they do not from the description) SQLite is probably the way to go. I like this tutorial but there are millions out there.
If they run somewhere ales (server) you can choose whatever system you are comfortable with since you will have to implement some protocol to communicate between mobile device and server anyway (most people would use HTTP/REST for that, but again, you can do that in a million ways)
SQLite is indeed better for Android applications.
In terms of preloading tables, schemas, and data into a Sqlite database, you can use the SQLiteManager firefox extension to do it.
Or, if you're too lazy to care about what types of database to use, might as well use ORMLite for Android to manage your tables and schemas within your Android application.
As for your server, you'll need to expose the API so that you can do HTTP/RESTful operations on it. You can choose whatever web applications that you prefer.
I'm trying to create some sort of backup & restore function in my app. Before that, I've been reading for a while to understand if it's possible to achieve, but I found out this question:
Sqlite DB Android Backup/Restore
The only other way I could see to do it, would be to read the actual contents of the DB and generate a file containing the SQL which which it can be restored from, this is obviously a more complex and doesn't offer any advantages to justify this complexity.
This answer, I think, is the best way to accomplish that; not explorting the .db file, but exporting queries.
You know; when you export a SQL data from mysql, you get a file which contains all the queries that creates the structure and queries that fill the structure with data.
That's what I'm trying to mimic; generate a file which contains sql queries from a .db file.
Do you guys think it's possible, I mean, is there any builtin method to achieve that?
Otherwise, if its too hard to handle, how do you manage to avoid what this user (https://stackoverflow.com/a/10842043/1943607) is talking about?
So, I disabled WAL with "PRAGMA journal_mode = DELETE" and then I was able to view the database in the browser and able to restore it on my test device fine.
That previous part, I can't understand it. Is this a configuration you set to sqlite?
Thanks
I haven't actually tried this with sqlite, but with mysql you could do things like create "dumps" of your database. Those dumps contained exactly what you describe: a set of queries that, when executed together, recreate the database, including the contents.
Judging from the "sqlite3" documentation found at http://www.sqlite.org/sqlite.html (especially the "Converting An Entire Database To An ASCII Text File" section), you can do the same for sqlite. Since you can execute shell commands from a java application (using Runtime.getRuntime().exec() methods), and you are the "owner" (Linux user id) of the database, you should be able to run this "sqlite3 .dump" command even on a non-rooted device. I have never seen an Android device without the sqlite3 tool installed, so the command should always be available.
Moreover, since dump file is just a text file, you should be able to prepend any PRAGMA's to it that are required for compatibility (like the one you quoted).
I haven't tested any of this, but just wanted to think with you on this interesting topic.
An sqlite database is just a file so you could copy the file but I think you may have problems with permissions in android preventing you from accessing the database.
A better solution IMO would be to sync your data to an external website.
Using a combination of a custom sync adapter and the account manager with a website or web service that has a RESTfull api to receive and send the synced data would be the most reliable approach.
http://developer.android.com/training/id-auth/identify.html is a great introduction to setting up the account manager.
And for a custom sync adapter this is a great starting point.
http://www.c99.org/2010/01/23/writing-an-android-sync-provider-part-1/
and http://www.c99.org/2010/01/23/writing-an-android-sync-provider-part-2/
And finally an explanation of how it all fits together
https://sites.google.com/site/andsamples/concept-of-syncadapter-androidcontentabstractthreadedsyncadapter
The above approach would enable a user to switch phones and retain data at the same time and the data would always be up to date (providing you sync at the appropriate times.
It seems like a lot of work as you will need to set up a web service but it is the BEST way to make sure data is kept safe and secure and can be restored and backed up at any point.
For a web service there are lots of options available to you including cloud services such as Google docs or writing your own website. Ruby on Rails is a great solution for developing your own site as you get a full RESTfull api out of the box and it;'s dead easy to secure/lock down a rails site to authorised users only with a couple of lines of code and with Heroku you can get free hosting.
As usual with Android development the simplest of requirements actually ends up being the most difficult to implement but where data safety is paramount then it's worth the effort to do it properly.
The question is too open to answer simply because the changes that may apply to the db file content are open and one can't guarantee a specific behavior .
On the positive side sqlite project is an open source and the format of the DB file is specified Here
After taking a look there, it seems very possible/not too complicated to parse any DB file looking for Data Only and write it/dump it to another functional db file.
I believe this is the fastest and cleanest solution to the issue in hand.
so to wrap up:
Copy DB file everytime you want to back it up.
When you want to restore create a new DB using Android APIs.
Parse the data from the backed up file and write them to the newly created DB.
P.S:
regarding how to use
PRAGMA journal_mode = DELETE
Simply use db.exec("PRAGMA journal_mode = DELETE"); when creating the DB
I have a huge set of data that I want to insert into the sqlite database before the user is able to do anything inside my application. Right now I have all my data stored in CSV files, then I parse those files and use DatabaseUtils.InsertHelper to do a bulk insertion, but this is taking to long to complete.
I stumbled on this tutorial some time ago and I'm wondering: is it safe to distribute a pre-generated sqlite file? Can I run into problems due to different versions of SQLite on different devices?
I'm planning to support Android 2.1 and higher.
I suppose it depends on your definition of safe. It is certainly possible as long as the database conforms to the metadata table spec Android expects, which is what that tutorial you stumbled upon is showing you. You won't have to worry about version conflicts with SQLite as that is a package built into the core platform and isn't something OEMs add to or implement anything on top of.
However, if by safe you mean "protected" you would need to take special steps to ensure that your database is not externally readable if that is a concern. If you simply place the preconstructed DB into assets/ and copy it over, anyone who can properly deconstruct an APK file can view your database data. This may or may not be an issue for you.
The best approach is to populate this data in the database, keep the database in assets & then copy it to the device ... You can follow this complete sample code here.