I need to sync my MySQL database to android phone. I am new to this. So I am referring this tutorial from Programmer Guru.
The Problem is in this tutorial they have used 3 classes, DBController, SampleBC.java, MyService.java. I have almost 10 tables to sync. So how can I change this to a better one?
Is there a way to sync the whole database?
I couldn't see correct tutorial for this.
This really depends on what your app does, and how it uses the remote data.
I have written apps which have an 'update' feature - which basically serialises the whole mysql database as json, and then decodes it in to the sqlite database on the device.
Other apps will just fetch a smaller amount of data as and when they need it.
There is no better way per se. Just different options for different situations. You need to look at how frequently your mysql data will change, and what will the experience be for your app users. Nobody likes slow apps which spend 50% of their time displaying a progress dialog while they download data.
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 am new to Android Application Development and a new member at stackoverflow. I am currently trying to design a recipe application. I have decided upon the features of the app and the scope it will cover. The scope is very vast for me in terms of covering all the recipes from all over the world. I am to deal with a lot of data in this process.
I am currently trying to figure a good and efficient way of handling the data in my app. So far, as per what I have read in different forums, I believe that I have two options in terms of a database choice : 1) SQLite 2) Database on remote server (MySql/Postgre)
Following are some of the thoughts that have been going on in my mind when it comes to taking a decision between the two :
1) SQLite : This could be a good option but would be slow as it would need to access the file system. I could eliminate the slowness by performing DB data fetch tasks in the AsyncTask. But then there could be a limitation of the storage on different phones. Also I believe using SQLite would be easier as compared to using a remote DB.
2) Remote Database : The issue that I can see here is the slowness with multiple DB requests coming at the same time. Can I use threads here in some way to queue multiple requests and handle them one by one ? Is there an efficient way to do this.
Also I have one more question in terms of the formatting of my data once I pull it out from the above DB's. Is there a way I could preserve the formatting of my data ?
I would be more than thankful if someone could share their knowledgeable and expert comments on the above scenario. Also this is not a homework for me and I am not looking for any ready made code solutions. I am just looking for hints/suggestions that would help me clear my thoughts and help me take a decision. I have been looking for this for sometime now but was not able to find concrete information. I hope I will get some good advice here from the experienced people who might have encountered similar situation.
Thanks for reading this long post.
What about combining both approaches?
A local SQLite database that has the least recently used receipes so you don't need network all the time. Network is way slower than accessing the filesystem.
Some remote database accessed via some HTTP interface where you can read / write the whole database. And if you want users to be able to add receipes for other users to see you'll need an external database anyways.
SQLite : This could be a good option but would be slow as it would need to access the file system.
Accessing a local database is pretty fast, 5ms or so if it's just a simple read only query on a small database.
But then there could be a limitation of the storage on different phones
Depends on your definition of huge database. It is okay if it is only 2MB which would be enough to store lots of text-only receipes.
Also I believe using SQLite would be easier as compared to using a remote DB.
Yes, Android has a nice built-in SQLite API but no remote database API. And you don't need to setup a database server & interface.
The issue that I can see here is the slowness with multiple DB requests coming at the same time.
A decent database server can handle thousands of requests. Depends on your server hardware & software. https://dba.stackexchange.com/ should have more info on that. Required performance depends on how much users you have / expect.
I'd suggest a simple REST interface to your database since it's pretty lightweight but does not expose your database directly to the web. There are tons of tutorials and books about creating such interfaces to databases. There are even hosted database services like nextDb that do most of the work for you.
Is there a way I could preserve the formatting of my data ?
You could store HTML formatted data in your database and display it in a WebView or a TextView (via Html#fromHtml()) - both can display formatted text.
Databases don't care what type of text you store, for transfer over the internets you may need to encode the text so it does not interfere with the transport formatting (XML, JSON, ...).
A simple way is to integrate Parse into your app. They have a nice framework that easily integrates into iOS and Android. Their plan is freemium, so you'll be able to use up to 1 million API request for no charge, and then its 7 cents for every request after that.
You'll have 1gb to store all your data sets / images, etc.
I don't use parse for everything, but I HIGHLY recommended it for large data schemes because they do all the scaling for you. Check out the API, I think it would be worth your time.
I just started to work on a few of my own projects, and I'm using Parse again. I have to say it's improved a lot over the last 6-8 months. Especially with the Twitter and Facebook integration.
The key issue here is the size of the data - any significant database of recipes would be too large to store on the phone imho,thus you seem stuck with the remote database solution.
As opposed to trying access the remote database from android I suggest you use a a go between web application that will process requests from the application and return JSON objects that you need.
It totally depends on your software requirements. If you need to deal with a small amount of data then you may choose SQLite, but for a huge amount to data better use a remote DB.
SQLite: It works fine with little amount of data & I experienced it response time is good.
Remote DB: I think you may use small server side app to submit the data to your client app. It will solve/reduce your thread related issues/complexities.
I have an Android app that needs to work offline and requires a lot of static data.
Currently I'm using a JSON file in the /res/raw and loading it with the Jackson parser into my POJO scheme. It works really well since I have an external program that will be generating this data and once in a while when there is a change I'll just publish new version to the Market so I don't have to deal with running an update server and so on.
However, right now my JSON file is about 2.5MB with limited dataset for testing, in the end it'll be about 5-10MB.
The issue is that it already takes about 3-5 seconds to parse the file and this needs to be done every time the application is restarted.
So, what are my options here? I could put the data to a sqlite database, but that would require rewriting the external application and changing the data structure quite a bit. But then I could only query the things I need at the moment and not loading the entire thing at once.
Is there some easier/better way? Also, is there a good way to publish the app with the sqlite database? All the articles I've found talk about creating the database for user data at first startup, but this is not user data and I need it to be deployed from the Market.
JSON feels like the wrong approach for this - it's a good way to encode data to transfer, but that's pretty much it.
It'd be nice to have a bit more info on what exactly your app does, but I'm struggling to imagine a use-case where having several MB of POJOs in memory is an efficient solution. I think it'd be much better to use SQLite, and this is why:
I could put the data to a sqlite database, but that would require rewriting the external application and changing the data structure quite a bit.
You can still use your other program's JSON output, but instead of loading everything into POJOs with Jackson, you could populate the database on first app launch. This way, the app boot time is negligible if the dataset is unchanged.
If you still want to work with POJOs in the rest of your app, it'd be trivial to write a query that retrieved data from the database, and created objects in the same manner as Jackson.
But then I could only query the things I need at the moment and not loading the entire thing at once.
What're you doing that requires access to all the data at once? Searching or ordering a set of objects is always going to be slower than a SQL query to achieve the same thing.
Also, is there a good way to publish the app with the sqlite database?
You can definitely ship your app with a database, though I've not done so personally. This is a relevant question:
By Default load some data into our database sqlite
Hope that's of some help.
There's an excellent API called JExcel (just google it) that works with .xls spreadsheets. If you're not going to be doing any selecting and just loading data from a source, I like to use JExcel because it's more manageable from a desktop and produces easier-to-read code.
Not sure of any performance differences, however. Just throwing in my 2 cents :p
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'm in the process of developing an Android application that will need to connect to a central database. Users should be able to access records and add records to the database through the application. The data itself will be fairly simple with each record being made up of a number of text fields.
The database will be developed specifically for the application and only needs to be accessed through the application. Initial reading seems to indicate that a web service should be written to parse data into xml format, for use by the app.
Seen as the database is being developed from scratch, specifically for this purpose, I would like to make sure I am heading in the right direction. I have very little experience with databases and would really just like a pointer on where to start reading. Any suggestions on the format the database should take would be greatly recieved too.
Thank you
You seem to have the idea down, if it were me, I would recomend using JSON instead of XML for the Webservice, they work in very similar ways, but JSON is a lot smaller and will make the application noticeably (as in it will make a diference for the user) faster. This is specially true if you are sending large amounts of data.
Take a look at this:
GSon
If your familiar with other aspects of Java, you could make the implementation entirely server side by means of JSPs. You could access the database via the phone's browser or any other browser. If you implemented a DAO factory on the server, this would enable you to switch databases from say Oracle, to MySQL etc by means of a properties file.