Question

I want to execute a SQL query in a method which permit to erase all data in my table. My solution work but I don’t believe that very clean and the jury will appreciate.

Right now, I call a method with date in parameter but I don’t need to use it. It’s the only solution that I have found. When I try to put a void, logically I can’t use this method which uses return.

public long Effacer(String date) {
    return ourDatabase.delete(DATABASE_TABLE, null, null);
}

Well for you what the way is the more clean for drop my table and recreate it. I had create a method une DbHelper but i don’t know after how i can call her. I believe that’s the way the more clean but i’m just a beginner so i’m not sure. What are you thinking ?

(i have let any of my tests in the code)
Here is my code :

HotOrNot.java

public class HotOrNot
{
    public static final String  KEY_ID              = "id_operation";
    public static final String  KEY_MONTANT         = "montant";
    public static final String  KEY_DESCRIPTION     = "description";
    public static final String  KEY_DATE            = "date";

    private static final String DATABASE_NAME       = "MyBudget";
    private static final String DATABASE_TABLE      = "Operations";
    private static final int    DATABASE_VERSION    = 1;

    private DbHelper            ourHelper;
    private final Context       ourContext;
    private static SQLiteDatabase       ourDatabase;

    public static class DbHelper extends SQLiteOpenHelper
    {
        // Constructeur
        public DbHelper(Context context)
        {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        @Override
        public void onCreate(SQLiteDatabase db)
        {
            db.execSQL("CREATE TABLE " + DATABASE_TABLE + " (" + KEY_ID
                    + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_DATE
                    + " TEXT NOT NULL, " + KEY_MONTANT + " TEXT NOT NULL, "
                    + KEY_DESCRIPTION + " TEXT NOT NULL);");
        }

        /* @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) */
        public void onUpgrade(SQLiteDatabase ourDatabase)
        {
            ourDatabase.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
            onCreate(ourDatabase);
        }

        public void onDelete()
        {
            ourDatabase.execSQL("DROP TABLE " + DATABASE_TABLE);
            ourDatabase.execSQL("CREATE TABLE " + DATABASE_TABLE + " (" + KEY_ID
                    + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_DATE
                    + " TEXT NOT NULL, " + KEY_MONTANT + " TEXT NOT NULL, "
                    + KEY_DESCRIPTION + " TEXT NOT NULL);");
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
        {
            // TODO Auto-generated method stub

        }

    }
    // constructeur
    public HotOrNot(Context c)
    {
        ourContext = c;
    }

    public HotOrNot open() throws SQLException
    {
        ourHelper = new DbHelper(ourContext);
        ourDatabase = ourHelper.getWritableDatabase();
        /*ourDatabase.execSQL("DROP TABLE " + DATABASE_TABLE);
        ourDatabase.execSQL("CREATE TABLE " + DATABASE_TABLE + " (" + KEY_ID
                + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_DATE
                + " TEXT NOT NULL, " + KEY_MONTANT + " TEXT NOT NULL, "
                + KEY_DESCRIPTION + " TEXT NOT NULL);");
                */
        //ourDatabase = ourHelper.

        //ourDatabase = ourHelper.onUpgrade(ourDatabase);*/
        return this;
    }

    public void close()
    {
        ourHelper.close();
    }

    public long createEntry(String date, String montant, String description)
    {
        ContentValues cv = new ContentValues();
        cv.put(KEY_DATE, date);
        cv.put(KEY_MONTANT, montant);
        cv.put(KEY_DESCRIPTION, description);
        return ourDatabase.insert(DATABASE_TABLE, null, cv);
    }

    public String getData()
    {
        String[] columns = new String[]
        { KEY_DATE, KEY_MONTANT, KEY_DESCRIPTION };
        Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null,
                null, null);
        String result = "";

        int iDate = c.getColumnIndex(KEY_DATE);
        int iMontant = c.getColumnIndex(KEY_MONTANT);
        int iDescription = c.getColumnIndex(KEY_DESCRIPTION);

        for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext())
        {
            result = result + c.getString(iDate) + " " + c.getString(iMontant)
                    + " " + c.getString(iDescription) + "\n";
        }

        return result;
    }

    public String getSolde()
    {
        // Création de notre requete et alias
        String query = "SUM(id_operation) AS " + KEY_ID;
        String[] otherColumns = new String[]{ query };
        Cursor cursorBidon = ourDatabase.query(DATABASE_TABLE, otherColumns, null, null, null, null, null);
        cursorBidon.moveToFirst();
        int iOperation = cursorBidon.getColumnIndex(KEY_ID);
        String monSolde = "";
        monSolde = monSolde + cursorBidon.getString(iOperation);
        return monSolde;
    }

    /*
    public void Erase(SQLiteDatabase db)
    {
        db.execSQL("DROP TABLE " + DATABASE_TABLE);
        db.execSQL("CREATE TABLE " + DATABASE_TABLE + " (" + KEY_ID
                + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_DATE
                + " TEXT NOT NULL, " + KEY_MONTANT + " TEXT NOT NULL, "
                + KEY_DESCRIPTION + " TEXT NOT NULL);");
    }*/

    public long Erase(String date)
    {
        return ourDatabase.delete(DATABASE_TABLE, null, null);
    }

}

SQLiteExample.java (only part when we click on delete button)

        case R.id.bSQLDelete:
            boolean samarche = true;
            try
            {
                String date = sqlDate.getText().toString();
                HotOrNot entryyy = new HotOrNot(SQLiteExample.this);
                entryyy.open();
                //entryyy.Effacer(date);
                entryyy.close();
            }

Answer 1

I don’t know why some people have judged me negatively, we cannot say i have do nothing efforts, we can see any of my test in comment. Moreover i’ve a solution which works for my problem, if i had not searched i would never found this way. The problem was just the way to do it and the fact i would like anything of clean, so we can say my post was only created by interest in computing.

Well, because i’m not like people which critize without help i give you the solution because personally i think to the other.
This is solution has been found by one people in my company. The solution for call the method onDelete in the class DbHelper is :

DbHelper dbHelper = new DbHelper(arg0.getContext());
dbHelper.onDelete();

With Regards,