I create Database in DB Browser For SQlite.
simple database - with one table called Students with two row:
1.id - integer
2.name -text
I want to use this database in android studio app.For example I need an app,which will print the names of students from database Students;
I've two questions:
Where Should I put the Students.db file?
How to use/read the database in my app.
I'm searching for it for a while but cant find solution.
Can you give me a good tutorial or just answer the question.
Thanks
There is a well defined pattern of making a "DataBaseAdapter" class in Android.
http://android-er.blogspot.com/2011/06/simple-example-using-androids-sqlite.html
Has an example.
you create a class SQLiteHelper that extends SQLiteOpenHelper. Then you follow the general pattern that the SQLiteAdapter class follows. This approach handles creating the sqlite db for you within your app-private internal storage.
To read from the DB, you make an instance of your SQLiteAdapter class, and then call insert(...), delete(...), query(...), etc. to actually manipulate your db.
Basically you would like to use an existing sqlite database, I think this question rely on a same idea, that answer could help you too.
Or if you don't have to use an exiting database file, your starting point can be this tutorial.
Related
Am a newbie to android development. I would like to have suggestions for setting up database during installation and populate the data in the tables.
As tables creation, data population in tables is a one time process which will be done during App installation, how can we write a program which will meet this requirement.
Thanks in advance!
You cannot setup database during installation. You can however do one of two things:
Ship your application with a ready made database.
Have your database created for you the first time it is needed.
If you prefer to go with option 1, you should extend an application class and have your databases created for you on the onCreate() call there. Refer to this for help. If you want to use option 2, you should understand the database lifecycle, most important thing being, when you are trying to access your database but it is not there, the system calls the onCreate() method of the class that extends SQLiteOpenHelper class. Refer to this url.
I'm creating an Android app that will download XML data from my website, parsed xml data will be inserted into 5 separate SQL Lite tables. I have successfully logged into my website, got the XML data & parsed. I not sure how to layout the database code for multiple tables(opening, closing, inserting, selecting).
Also I would like (is this possible) these tables to stay on the device if the user needs to logout and come back to the app at a later time.
Any help or direction would be appreciated.
Thanks
Question title says "multiple databases", body says "multiple tables". I take it to mean "multiple tables".
Just use SQLiteOpenHelper. Create all the tables in onCreate(). Do the opening/closing and CRUD operations the same way you would do on a SQLiteOpenHelper hosting a single table.
Use a search engine to find tutorials about SQLiteOpenHelper in case you need them.
I have an app which requied more than one table.
The DB is mosly for read purposes and i want to know what is the best way to manage my tables.
I tought about 2 options.
Create new DB class with new DB for each table.
Create new table in the exits DB.
What is the best for better performance in reading?
hat is the best for better performance in reading?
For sure don't create new database but put all tables you need in one database. Reasons are more there, for instance now you don't know whether you will need sometime in a future to create some relations between these tables.
I's not "good" to have more db files which will represent one table, it's not comfortable and efficient as well. So my suggestion to you is to keep only one db file and put all tables in this one.
The best approach to manage SQLite database is to use SQLiteOpenHelper class that wraps all required logic for reading and writing from/to database. Then, SQLiteDatabase itself provides some API methods for inserting, updating and deleting from db.
At the end as my personal recommendation. If you'll have more than one table just how i mentioned create one SQLiteOpenHelper subclass for creating database and then for each table create object that will represent table "in objects" e.q. columns in table will become properties of object.
Finally for each table create DAO classes that will wrap CRUD operations and some specific methods for each table.
If you don't know how to start check these tutorials:
Android SQLite Database and ContentProvider - Tutorial
Android SQLite Database Tutorial
You can use SQLiteDatabase.
SQLiteDatabase has methods to create, delete, execute SQL commands, and perform other common database management tasks.
Database names must be unique within an application, not across all applications.
Read: Documentation
I am developing an App in which now i have to create database for more better user experience. Then i came to know about DB4o which is many times faster tool for creating database than other like SQLite, MySql etc, but the problem is i am not able to find any single example that explains about DB4o and how to create database using Db4o. If anybody has used it, please post an example or send me link.
To store the object in database use
db().store(exercise);
To retrieve All records from database, use
db().query(Object);
To retrieve particular record from database, use
db().queryByExample(Object);
If you need example, Try My blog example using db4o.
In this example, simple student object will be stored in database using db4o. Student object will contain student name, register number, and his age.
Thank you.
I'm developing an Android application that access many tables from a SQLite database.
I need an example to see how implement a database framework to access multiples tables. I've been looking for and I only find examples with one table.
UPDATE:
With one table I found only one class DBAdpater with object SQLiteDatabase and a class myDbHelper extends SQLiteOpenHelper.
With many tables I think I need one DBAdapter for each table. So, I think I need to share SQLiteDatabase object between each DBAdapter, isn't it? To open database, close, execute SQL stament...
I think I need one DBAdapter because I don't want a enormous DBAdapter class.
Any suggestions?
Thanks.