I'm new to programing for android and i'm still learning. So I have a question about the location of the SQLite database. Is it stored in the same file system as the application ?
And also i'm not sure can the database be created before the app is installed(can it come with the app) or can the database only be created from inside the app ?
And what if i wanted my app to come with a database that already has tables and records which is local and not on a server. Would that be possible ?
SQLite is available on every Android device. Using an SQLite database in Android does not require any database setup or administration.
You only have to define the SQL statements for creating and updating the database. Afterwards the database is automatically managed for you by the Android platform.
Access to an SQLite database involves accessing the filesystem. This can be slow. Therefore it is recommended to perform database operations asynchronously, for example inside the AsyncTask class.
If your application creates a database, this database is by default saved in the directory DATA/data/APP_NAME/databases/FILENAME.
The parts of the above directory are constructed based on the following rules. DATA is the path which the Environment.getDataDirectory() method returns. APP_NAME is your application name. FILENAME is the name you specify in your application code for the database.
You can also follow this tutorial for further understanding.
http://www.androidhive.info/2011/11/android-sqlite-database-tutorial/
Database is created after the app installation or after the db changes. The db is stored in /data/data/your_package/databases/
Related
Perhaps I am missing something because I couldn't find anything about this. I want to use Android Room to store my data locally on the device. How do I ensure that it is a single data base, not a new instance each time? Is it by class name?
When you build the Room Database and then access the built database it opens the database (or creates it if it doesn't exist (once unless the App is uninstalled)).
The database itself is a file and is typically stored in the App's data (data/data/the_package/databases), thus the data belongs to the App. The file persists (is effectively permenant).
If your concern is regarding a pre-packaged database (i.e. a database created and typically populated elsewhere (e.g. an SQLite management tool) and is supplied as part of the APK), then the App would copy the database from the APK prior to building/opening it.
As such creating the instance (build followed by access) is in effect opening the file rather than creating a new database everytime.
Where does Room store the database and how can I force a rebuild of the DB? I've tried looking for the DB under:
data/data/com.me.myapp/No database directory here
data/user/0/com.me.myapp/No database directory here
I want to see exactly what data is in the database using SQLLite so I followed these directions "Access database in Android Studio" but I only see a cache and codecache directory stored there. No database directory.
The reason for wanting to see the DB is that I changed the model to add a few fields, but I can't figure out how to force Room to recreate and repopulate the DB with data. I added breakpoints inside my data generator class; however they don't seem to ever get hit.
if you change your entities structure (aka add fields) then in order not to loose data and get the fields added when user updates the current version of the app you need to implement migration . See the docs how to do it. So updating the app version will make your db "rebuild" and not lose data. When I just work with test version I delete app and build it on device again it'll implement the changes in db structure but you'll lose the data.
You should definitively see db files in the directories you named.
If you want some other method to debug a database you could use this library git link
I am not quite getting the idea of sqlite database. I am developing a hybrid mobile app using Ionic Framework and backend with PHP.
I referrred to this article for using the sqlite https://blog.nraboy.com/2014/11/use-sqlite-instead-local-storage-ionic-framework/
I have a few questions now,
1) So, anybody can create a table,insert and do any kind of operations? Is'nt there any need of a security method to access the DB like mysql?
2) Is a separate instance of Sqlite created for each application? Coz if not,I can make a guess for a tablename created by any other application and delete it all together,isn't it? I just dont get it?
1) SQLite is a file database so if you have access to file you have access to database and can do anything with it. What is the purpose of restricting access to db when you can just delete whole file? SQLite db file should be created in app private storage so no one have access to it only your app.
2) the answear is above. just create file in right place and everything will be fine :)
1) So, anybody can create a table,insert and do any kind of operations? Is'nt there any need of a security method to access the DB like mysql?
By default, each app db will store in their private folder(data/data/your_package_name/database and only that app or system app can access to it.
But if you choose to store your db in sdcard, anybody can mess up your db if they know the path to db file and have right to access it.
Other case is if your device is root, other apps can access your db too.
2) Is a separate instance of Sqlite created for each application? Coz if not,I can make a guess for a tablename created by any other application and delete it all together,isn't it? I just dont get it?
Like above, each app can choose where to store their db file, so basically, they a separate instance.
You can also create multi db file for one app if you like.
I have an app that creates a database and do some stuff. I am wondering if i upload a new db to a server and download it to the exact folder where the older one exists it will be overwritten and i am good to go? Or there will be a problem. Assuming it has the same name, same column names, etc. Of course i am reffering to sqlite.
In Android, when performing a database update you should be using onUpgrade inside of the SQLiteOpenHelper. One way of doing this is to download text files that include the sql instructions needed to modify the current database or update rows with new data. The reason you have to do this is because Android will only create the database once. After the initial creation the call to onCreate for the database will not occur.
I want to only read data from the SQLite database. When I am creating database and reading it it is working but I have already a database created and I want to read data from this database.
I am pushing the database to the sdcard and trying to run the application but it is not reading form the database. I want to know that if install this .apk file in device then my database will also shift to the device or not.
Common practice is to store initial data on assets/raw folders of application resources. Then during 1st run just create DB using SQL scripts like:
create table if not exist
Fill DB with initial data - and here you're.