Develop Reference

android auto sync mysql to sqlite [duplicate]

I am developing an android application. I want to update the local SQLite database with MySQL database on server. I am not able to figure out that what is the most appropriate and standardized way to do so?

Create a webservice (REST is probably best) and serialize your SQLite/MySQL data and PUT/POST/GET it to/from your web service. This will give you a nice layer of abstraction in case you decide to switch from MySQL to something else server side.

You may want to take a look at fyrecloud.com/amsler This is source code for a demonstration Android application that implements MySQL replication between a MySQL server and the SQLite db on an Android device.
Amsler rests on two pillars:
It communicates with the MySQL server using the MySQL Client/Server protocol in order to connect to the server for authentication and for receiving replication events as they occur.
It uses the Antlr lex and parse software in order to lex and parse incoming replication events and then to translate the MySQL commands into equivalent SQLite commands.
This is great for one-way replication. You can simulate two-way replication by modifying the MySQL server indirectly via RESTful type methods and then watching while MySQL sends a new replication event back.
Accessing a server via REST is easy enough. However, modifying an existing MySQL installation in order to support serialization presents too many headaches to enumerate here. Amsler takes advantage of pre-existing replication services. REST also depends upon some polling strategy in order to keep the local device reasonably up-to-date. Again, many problems with this approach. Amsler maintains a TCP/IP connection to the server which enables server-push notification of updates.
The most difficult part of Amsler is in figuring out the lexing/parsing. The Syntax between MySQL, SQLite, and the various versions of the same have many subtle differences. So many differences that it's impractical to provide a shrink-wrap translator and instead you must resort to modifying the grammar yourself.
Nevertheless, good, bad, or ugly, here it is. Take a look and maybe the glove fits.

This is probably going to be helpful: sync databases Mysql SQLite
The real answer is that there is no standard or built in magic way to just copy a MySQL database that lives on a server somewhere to a device. You will have to implement either a webservice or somehow convert the MySQL db on the server to the android sqlite implementation and download that file into your app's data directory (not a route I'd recommend taking).

Late to the party, but http://www.symmetricds.org/ is a good solution.
Java, runs on Android too.
LGPL.
Can handle 10,000's of clients.

There is no standard way. Depending on your needs you can e.g. use webservices in REST or SOAP protocols or more binary data exchange.

Sync data between client and server

I have mobile app. Something like to do list or calendar. Teoretically user can have a few devices with that application on a defferent platforms and so on. I would like to create a automatic synchronization between them through a own server. What is the best practice: update all the information or only the changes? On the one hand usually there is no a lot of data when it's about a to do list but who knows?

The correct approach is not date/time as others suggest, as time can go out of sync. The right algorithm is to keep the checksum of the data entries during last synchronization. On next synchronization you compare current checksums with stored ones, then you know whether the entry has been changed on the server, on the client or both.
Our open-source Rethync SDK lets you implement the above approach quite easily and is available for Android (not for iOS at the moment).

I am doing something similar in my application. I have a last modified date field with each entity that I need to sync. Then periodically, I post this data to the server (actual data + date and time). Now the server can do one of two things. It will check the corresponding data on server side and compare the last modified date. If what the server is latest, it will return the latest data in response. If not, it will update its data and send a response indicating what client has is latest.
Of course you can do several optimization. That is, mark the data as "dirty" so you know whether to even send your data to server. If the phone does not have modified data, your sync is basically getting the latest data from server.
Basically server does the heavy lifting and does all the logic necessary to maintain the latest data on its end and send responses to client appropriately.
Good Luck

Best approach is use a time stamp to handle this.
Initial request to server with time stamp value 0.
Server will give the all the data first time with Time-stamp.
Store the Time stamp to sharedpreferences.
In All next request pass the time stamp back to the server
Server will send only those data which are add/update/ after that
given time stamp
That is it.

There is a new alternative to the syncing problem. It's called EnduroSync from Orando Labs. You can sync object data stores between devices on Android and iOS now, with others coming soon.
Full Disclosure: I work for Orando Labs.
The EnduroSync clients allow you to create object data stores on the local devices. The clients are fairly sophisticated - data is modeled as native objects for each client we support (iOS and Android now, more coming). The clients work offline and online. The data is saved to an sqlite database locally.
As you change objects in your model, the deltas are recorded on the device. At some point, you can 'sync' the object data store. Syncing uses a commit/push/pull process (like git), but this is invisible to you. The sync brings your local copy up to date with whatever is on the server, and sends up any changes you have made. Conflicts are resolved using a timestamp based merge, so newer data is not overwritten by older data.
EnduroSync is an online service, so there is no server setup on your end.
There is also a flexible permission system which lets you share the object data stores in a variety of ways. For instance, most applications will have one or more object data stores for each user, for preferences, notes, tags, etc. You can also share object data stores per app, per user type, and with wild cards, many other ways.
So basically you use our client SDK's to model your data on the device. Modeling is with simple objects in the native programming language of the device. If you sign up for the syncing service, you get the syncing also.

Here is another approach.
Issue :I need to have the appointments of doctors syned to client (mobile device) from the server. Now the appointments can drop off or the data could possibly change on the server. Having the client to know what change and sending a request back to server could be an expensive service.
Possible approach : Have the server do the heavy lifting. Keep a table which stores values of time stamp and if a change happened with regard to an appointment - cancellation / reschedule etc. The client would then look at this table to see if anything changed. In reality we don't need to sync anything but only the delta which server can provide to the client based on what it has and what is at Client. There is one aspect which needs to be taken care of is updation of info from client to server and traditional conflict management can be done where client can update the server when a data connectivity between client and server exists.
Essentially the approach is to have only the deltas synced by maintaining a checksum or data change log to PUSH changes to the client.

Android apps connect with database server

I am trying to learn to implement android apps to get news, promotion message, and calendar from server. What is the best and easy way to communicate with database server? using JDBC or other methods?
Thanks

Using JDBC?:
In the words of Commonsware:
Never never never use a database driver across an Internet connection,
for any database, for any platform, for any client, anywhere. That
goes double for mobile. Database drivers are designed for LAN
operations and are not designed for flaky/intermittent connections or
high latency.
On the client side (Android app), you can use SQLite to store data locally. It might not be necessary at all actually. For instance, it can be used for offline features, search, etc. For client-side, read up on this simple post
On the server side (whatever server side technology you know or want to learn), you can use whatever language, whatever database on whatever server OS you want. This part is commonly called the back-end, which will store your data while your app communicate with it through HTTP.

You can use json to parse data between server and the android device. In the server you can use jdbc with json if you are using servlets in the server.

To communicate between a server and an android device you can use JASON. See following links for some help.
http://www.androidhive.info/2012/01/android-json-parsing-tutorial/
https://www.learn2crack.com/2013/10/android-asynctask-json-parsing-example.html
https://www.learn2crack.com/2013/10/android-json-parsing-url-example.html
Also in the device to deal with data within the device you can use SQLite. And in the server you can use jdbc if you are using servelets.

To communicate with Database server You should use web service API such REST , soap

Up-Sync and Down-Sync in Android?

I am working on a Point of Sale application that needs to be very good syncing mechanism. We have Magento Database.The android device have SQLite local Db. Now we need to sync in the following way:
Local ------Sync To---------------> Server (Up Sync)
Server------Sync To---------------> Locals (Down Sync)
There are 2 things:
1) write-to (How to take care??)
For every change that i do on local ,it will directly sync my local to server
2) write-back (How to take care???)
Whenever there is a change in server, we need to sync all our locals with server.
So, the task is: to identify a server update
And sync our locals.
Like there are 4 devices are running in a store and we have added one new customer through one device. Now i want that the three other devices local db also updated with the information about that customer and server also updated.
I heard about the background threads and run threads after a time interval. But what is the best way to do that which don't affect the application. Also the all Big Retail stores uses the syncing process. what they used for that ?
Any help is appreciated.

It fully depends on you database structure...
you have DATABASE in LOCAL (device) and on SERVER
NOW
You need to have TIMESTAMP fieLd added to the TABLES which actually you want to keep in SYNC.
When ever you will make any changes on server the TIMESTAMP will be updated there and same will be the case for the local database also what you have to do is now.
Run a service in the background which will keep on comparing the TIMESTAMPS of LOCAL with that of SERVER.
Now you have to put condition that if TIMESTAMP of SERVER is newer to that of LOCAL then bring changes from SERVER to LOCAL,
and vice versa will be the condition to take changes from LOCAL to SERVER.
Further you have to decide how frequently you want to run this SERVICE.
ALTERNATIVELY:
You can make the table there on SERVER which will store LAST_SYNCHED date for particular device
Whenever you will login in you device (or any other particular event on which you want it to perform this) the server will check-
when this device was LAST_SYNCHED
then it will compare it to TODAYS DATE
and will check what upadets actualy happened between these dates and
will send the changes to the LOCAL (device)
and vice versa for LOCAL (device) to SERVER
you have to play with TIMESTAMPS rest you can have your own logic how to structure the database.
I told you what I have have observed, when I have been a part of such similar project
EDIT
The above Process defines how to sync the devices with server I mean the strategy..
If you want your devices to get notified from server when to sync instead of hitting the WEB-SERVICE recurrently ..
You can make use of PUSH NOtification, GCM is one of them that send push notification to devices, you can integrate it to your project

For syncing you need to handle following two situations.
How and when to receive server updates
How to identify local non-synced data
How and when to receive server updates:
For receiving updates, we can use GCM (Google Cloud Messaging). If any updates made in server, server sends a push message to all devices. Devices will receive that push and based on the message, devices will download the data from server. (I think this is better approach than continuous hitting service for some particular intervals like polling)
For receiving only updated data from server, server maintains modified_timestamp column for all tables. First time devices will send empty timestamp, so that server sends all data to the device with server timestamp. Device receives the new data and updates local db and saves the latest server timestamp. For next time to get server updates, device will send stored server timestamp then server will send only modified data after that timestamp only. For each response server sends server timestamp, devices needs to store that timestamp and needs to use while calling service.
How to identify local non-synced data:
For sending local updates, local db needs to maintain one 'isSynced' column in tables. If any row modified in local isSynced will be false, after successful syncing local data to server isSynced will be true. so that we can handle local data up to date with server.
Updated:
You can find more information on this developer link

Have you considered using commercial solution?
http://www.mobeelizer.com/ seems like what you want to achieve. There are probably many other.
Note: no affiliation with that company.

I would say that the problem statement is incomplete. In above described setup what is missing is what actually you are going to synchronise.
Usual case in POS is that there exist few indices (id,value,...) tables that shall be distributed from central server to the client devices. In most cases it is price list, stock list, etc. Those tables should rarely be modified on client devices (actually could but then has to be redistributed from central server and acknowledged by client devices).
The other direction tend to be also pretty straightforward on client device you generate bills or invoices. These are again local stuff that shall be propagated towards server. Thus you actually store them locally and at sync point dispatch them to the server. Later on you might receive your own items back from server as an acknowledge.
EDIT: to detect changes, on-write timestamps as mentioned above is a must.
So far above described is the data flow.
Next you have to move into solution domain and implement these rules. There is couple of sync approaches (i.e.SyncML). On the other hand keeping it simple rulez. Thus the main concern should be some kind of locking and queueing that makes the thing robust.
It could also use the agent based client, in such case each device has it own agent (could be replica of last known state of the device db) but I would consider this as an advanced feature that might come in future release:-)

I am also working on the sales app in which i have to my local goals to server and server goals to my local goals
My proceder is that when ever my app is started i get the latest data from my server of my all my member and update my local data base with this data and when ever i change data in my local data base also update on sever side
also i used a sync button which will fetch latest data from the server if my team member changes its goal or profile

IF you want updated data on all the devices, why don't you use remote database only, why are you introducing local database for this.
For your case i will suggest you to work with only remote database directly so the things can be done real time.

Sync SQLite Database to App Engine Datastore?

The android app stores the data in SQLite database during the offline mode. When online I want the app to sync (in both direction) with the datastore(database) in cloud server (App Engine). How do I implement this functionality, so that I can show the data captured on phone on a web application. Also please suggest any simple alternative way if any..

I just write out my data as a String (using a format I can reconstruct my data with), pass that to AE, parse it and store/display it.
You could use json too.
or try http://mylifewithandroid.blogspot.jp/2010/10/client-server-communication-with-json.html
for the sync part I use a timestamp. If the timestamped result isn't recorded on the server, I record it. I send back the recorded stamps to the client and delete them from the store. Of course the server can also send back new results if a user's records were updated from a different client.

In general, you should implement some complex algorithm, that will be doing synchronization depending on your needs, and then make it in code on both side (server and client). This not quite a simple task, in general. Useful keywords for googling: SOAP, REST, JSON, ...