Android - What is the difference between getReadableDatabase() and getWritableDatabase()?

Question

I was able to enter information in the database using the method getReadableDatabase(). In that case shouldn’t it be wrong? Shouldn’t it be the method getWritableDatabase()?

private void savePet() {

        petDbHelper = new PetDbHelper(this);
        db = petDbHelper.getReadableDatabase();

        ContentValues values = new ContentValues();
        values.put(PetEntry.COLUMN_PET_NAME, mNameEditText.getText().toString());
        values.put(PetEntry.COLUMN_PET_BREED, mBreedEditText.getText().toString());
        values.put(PetEntry.COLUMN_PET_WEIGHT, mWeightEditText.getText().toString());
        values.put(PetEntry.COLUMN_PET_GENDER, mGender);

        long newRowID =
                db.insert(PetEntry.TABLE_NAME, null, values);

        /** Display rowID after finish */
        Toast.makeText(this, "New row added: " + newRowID, Toast.LENGTH_SHORT).show();

        /** Close Activity */
        finish();
    }

Answer 1

According to the documentation, the getReadableDatabase():

Create and/or open a database. This will be the same Object returned by getWritableDatabase() unless some problem, such as a full disk, requires the database to be opened read-only

Translating:

Creates or opens a database. This will be the same object returned for getWritableDatabase(), unless a problem occurs, such as for example: if the disk is full the database is opened in the read-only mode.

But looking at the documentation of getWritableDatabase(), it says that if the disk is full, this method will return an error.

In short: Both return the same object, so there is no error. But you should use the getWritableDatabase() to save data to better handle errors that may arise.