I would like to synchronize the database of an Android app with the new Dropbox SyncAPI.
I don't understand very well the tutorial on https://www.dropbox.com/developers/sync/tutorial/android,
and the example of the "Notes" is a little confusing for me. I can still log in to the platform with the API, and I know that I should use the database as a single file to be treated, obtaining its path.
My questions are: what are the main key points to do this (handler? listener to file?)?
Where can I find other examples to study for my case?
Thanks.
Related
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 would like to maintain single sqlite DB for two applications. I have seen other links and this was helpful Share SQLite database between 2 android apps?
But still when I declare the shared user ID and shared context, I could not achieve it.
In my first app- SQLite is created with few tables.
In my second app=- I would to create tables in the same DB which I created in first app
And also in few posts, I read that this can be achieved through remote Database.
Please can some one suggest me good tutorial where I can have some idea on how to proceed?
I would recommend what you've asked about - which is using a remote database.
Check out this: how to use free cloud database with android app?
Look into a hosted database in the cloud. Quite a few of them will let you get started for free. I know IrisCouch lets you get going for free and it's very easy. http://www.iriscouch.com/ The nice thing about CouchDB is you can do all your work via HTTP - which isn't too hard from an Android device.
Hello everyone first of all.
I am making an application for android, which I need to have a database for information.
The database management computer mailbox.
What I need is to take that database and included in the application for android'S SELECT generally.
I've been testing it on this website, but I can not get it to work. I do not think either the DB copy to memory, and then to perform the query, she says she can not find the table.
I have been debugged and saw that even the open works, but something strange happens ...
If you have some method or way of doing this, I would really appreciate it.
Thanks for everything.
Check out these resources
This tutorial by Lars Vogel
This reference article from Android website
Puit it in your assets directory in your apk, and on first use copy to "/data/data/YOUR_PACKAGE/databases/" directory. Here is SO discussion on this topic. database in assets folder
I have zero experience with databases, and am looking for some direction in getting started. I am making an Android app that needs to read in a large amount of data quickly... Eventually this will be a stock market app that accesses real-time stock information. But before I spend money trying to get access to such real-time data, I'm working with a Microsoft excel file that has times and information on stocks from the past.
I've read up on databases and apparently Androids come with SQLite but I can't figure out how to start using it, or how to import my excel file.
Please help get me started or point me in the right direction. I've found some tutorials but they were difficult for me to follow with my complete lack of experience, and not necessarily related to my project; I'd need really basic step-by-step instructions...
Here is one way of doing this, think only in terms of data you need, rather than trying to get all spreadsheet data into your SQLite DB.
So, think in terms of learning basic SQL and SQL queries and create the tables (on a piece of paper) you need, how you will manipulate the data in these tables (updates, inserts, deletes etc).
Now that you have the table schema and your queries, the task remains of importing this data into the tables. For this I haven't done this but I am sure you will find a lot of resources on the Internet.
Now, as you can see, the seemingly complicated problem is broken into tangible actionable steps.
Here is a reasonable tutorial on SQLite. Here is another for SQLite and Android. You can google for more help.
Also take a look here. The blog talks about importing from excel into SQLite DB.
I am new to android.
I have an application where i am calculating the loan amount based on salary. For that I have a database of salary,Tax and medicare column. The tax and medicare depends upon the salary bracket. I want to know how to create the database and access it through the coding.
If any good sample code example is there please give the link.
Thanks in advance.
Here you can find a simple and straight forward tutorial from anddev.
Summarize from the tutorial:
Description: We'll need to to the
following things:
Create a DataBase (generally this is done just once)
Open the DataBase
Create a Table (generally this is done just once)
Insert some Datasets
Query for some Datasets
Close the Database
Android uses the SQLITE database Read up on it here: http://www.screaming-penguin.com/node/7742
I assume you have read the official Android developer guide. If not, there is a wealth of information about doing anything and everything you'd want on an Android device.
Since Android uses SQLite as it's internal database, I'd suggest reading documentation about it + the data storage part of Android guide.
These would be good starting points.
You may try this simple tutorial with nice graphics illustration.