Question

I’m developing a simple Android application with SQL. I followed the following guides – Using your own SQLite database in Android applications

I get an error when trying to do a query the database.

Here is my DataBaseHelp.Java Class :

package namae.nombebe;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;

public class DataBaseHelper extends SQLiteOpenHelper{

    //The Android's default system path of your application database.
    private static String DB_PATH = "/data/data/namae.nombebe/databases/";

    private static String DB_NAME = "myDBName";

    private SQLiteDatabase myDataBase; 

    private final Context myContext;

    /**
     * Constructor
     * Takes and keeps a reference of the passed context in order to access to the application assets and resources.
     * @param context
     */
    public DataBaseHelper(Context context) {

        super(context, DB_NAME, null, 1);
        this.myContext = context;
    }   

  /**
     * Creates a empty database on the system and rewrites it with your own database.
     * */
    public void createDataBase() throws IOException{

        boolean dbExist = checkDataBase();

        if(dbExist){
            //do nothing - database already exist
        }else{

            //By calling this method and empty database will be created into the default system path
               //of your application so we are gonna be able to overwrite that database with our database.
            this.getReadableDatabase();

            try {

                copyDataBase();

            } catch (IOException e) {

                throw new Error("Error copying database");

            }
        }

    }

    /**
     * Check if the database already exist to avoid re-copying the file each time you open the application.
     * @return true if it exists, false if it doesn't
     */
    private boolean checkDataBase(){

        SQLiteDatabase checkDB = null;

        try{
            String myPath = DB_PATH + DB_NAME;
            checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

        }catch(SQLiteException e){

            //database does't exist yet.

        }

        if(checkDB != null){

            checkDB.close();

        }

        return checkDB != null ? true : false;
    }

    /**
     * Copies your database from your local assets-folder to the just created empty database in the
     * system folder, from where it can be accessed and handled.
     * This is done by transfering bytestream.
     * */
    private void copyDataBase() throws IOException{

        //Open your local db as the input stream
        InputStream myInput = myContext.getAssets().open(DB_NAME);

        // Path to the just created empty db
        String outFileName = DB_PATH + DB_NAME;

        //Open the empty db as the output stream
        OutputStream myOutput = new FileOutputStream(outFileName);

        //transfer bytes from the inputfile to the outputfile
        byte[] buffer = new byte[1024];
        int length;
        while ((length = myInput.read(buffer))>0){
            myOutput.write(buffer, 0, length);
        }

        //Close the streams
        myOutput.flush();
        myOutput.close();
        myInput.close();

    }

    public void openDataBase() throws SQLException{

        //Open the database
        String myPath = DB_PATH + DB_NAME;
        myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

    }

    @Override
    public synchronized void close() {

            if(myDataBase != null)
                myDataBase.close();

            super.close();

    }

    @Override
    public void onCreate(SQLiteDatabase db) {

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }

        // Add your public helper methods to access and get content from the database.
       // You could return cursors by doing "return myDataBase.query(....)" so it'd be easy
       // to you to create adapters for your views.

}

And this is the way i open my database :

    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        DataBaseHelper myDbHelper = new DataBaseHelper(this);

        try 
        {
                myDbHelper.createDataBase();
        } 
        catch (IOException ioe) 
        {
            throw new Error("Unable to create database");
        }

        try 
        {
            myDbHelper.openDataBase();
        }
        catch(SQLException sqle)
        {
            throw sqle;
        }

        myDataBase = myDbHelper.getWritableDatabase();

        Cursor c = myDataBase.rawQuery("SELECT * FROM Astuces", null);
// problem on this query
    }

So the query doesn’t work. (if i don’t put it application work)

I have a Table Astuces.

Errors :

07-30 10:56:53.869: E/AndroidRuntime(503): java.lang.RuntimeException: Unable to start activity ComponentInfo{namae.nombebe/namae.nombebe.NomBebeActivity}: android.database.sqlite.SQLiteException: no such table: Astuces: , while compiling: SELECT * FROM Astuces

We can see I say there are no table Astuces I really have it so I didn’t understand why i can find it.

Answer 1

I followed the same link, couple of weeks ago. There are some important things that you must consider before you start to use the codes:

1 – you need to add a table to your SQLite file calls android_metadata and then insert en_US to it.

2 – you must rename the id to _id.

3 – you should copy your SQLite file to the assets folder of your project.

Then you can use the codes. How you done these 3 steps?

Where is myDataBase class? Where did you implement these methods in your code?

myDataBase = myDbHelper.getWritableDatabase();
Cursor c = myDataBase.rawQuery("SELECT * FROM Astuces", null);

You may need to have something like this in your DataBaseHelper class

public Cursor fetchAllEntries() {
            //includes all column names
        String[] projection = new String[] { KEY_ROWID, USER_ID, START, END };
        String restrict = null; // Get all entries
            String orderby = null;
        return myDataBase.query(TABLE_NAME, projection, restrict, null, null, null, orderby);
    }

and call it like this in the main activity:

Cursor entryCursor = db.fetchAllEntries();