android.database.sqlite.SQLiteException: no such column: user_id (code 1 SQLITE_ERROR): - database

Question

being an Android Studio beginner i tend to get lots and lots of tiny errors i cannot find out, please let me know what I am doing wrong because I've tried all the other answers somehow and it doesn't get better :)
public class DatabaseHelper extends SQLiteOpenHelper{
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "UserManager.db";
private static final String TABLE_USER = "user";
private static final String COLUMN_USER_ID= "user_id";
private static final String COLUMN_USER_NAME= "user_name";
private static final String COLUMN_USER_EMAIL= "user_email";
private static final String COLUMN_USER_PASSWORD= "user_password";
private String CREATE_USER_TABLE = "CREATE TABLE " + TABLE_USER + "(" +
COLUMN_USER_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ COLUMN_USER_NAME + " TEXT," + COLUMN_USER_EMAIL + " TEXT," +
COLUMN_USER_PASSWORD + " TEXT" + ")";
private String DROP_USER_TABLE = " DROP TABLE IF EXISTS " + TABLE_USER;
public DatabaseHelper(Context context){
super(context, DATABASE_NAME,null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db){
db.execSQL(CREATE_USER_TABLE);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion){
db.execSQL(DROP_USER_TABLE);
onCreate(db);
}
public void addUser(User user){
SQLiteDatabase db= this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(COLUMN_USER_NAME, user.getName());
values.put(COLUMN_USER_EMAIL, user.getEmail());
values.put(COLUMN_USER_PASSWORD, user.getPassword());
db.insert(TABLE_USER,null, values);
db.close();
}
public boolean checkUser(String password, String email){
String[] columns = {
COLUMN_USER_ID
};
SQLiteDatabase db= this.getWritableDatabase();
String selection = COLUMN_USER_EMAIL + " = ? " + "AND "+ COLUMN_USER_PASSWORD+" =? ";
String[] selectionArgs = { email,password };
Cursor cursor = db.query(TABLE_USER,
columns,
selection,
selectionArgs,
null,
null,
null);
int cursorCount = cursor.getCount();
cursor.close();
db.close();
if(cursorCount > 0){
return true;
}
return false;
}
}
I know the logcat let me know this:
07-11 22:08:29.072 9071-9071/com.example.lavinia.sqllogin E/AndroidRuntime:
FATAL EXCEPTION: main
Process: com.example.lavinia.sqllogin, PID: 9071
android.database.sqlite.SQLiteException: no such column: user_id (code 1
SQLITE_ERROR): , while compiling: SELECT user_id FROM user WHERE user_email =
?AND user_password =?
And I can't find the wrong usage of user_id, I think I used it fine and the app will stop working after I Login myself. (the app has login and registration activities- and the registration works ok, but pressing the Login button in the Login.activity will make the app crash)
Thank you very much for you support :) If needed, I will provide with further code.

Answer 1

This issue is probably due to i tend to get lots and lots of tiny errors in conjunction with a common misconception regarding the onCreate method.
The onCreate method automatically runs only once when the database is and has actually been created. It does not run every time the App is run.
As such any changes (corrections included) to the structure (tables and columns) will not be applied if they are coded/actioned within the onCreate method.
When developing the easiest fix is to do one of the following 3:-
delete the App's data (deletes the database so onCreate will be called).
uninstall the App (deletes the database so onCreate will be called).
if the onUpgrade method will drop the table(s) and then call onCreate , to increase the database version number as passed as the 4th parameter to the SQLIteOpenHelper sub-class (aka the DatabaseHelper class).
After doing one of the above, rerun the App.
NOTE any existing data will be lost.
If data has to be retained then a fix is more complicated but would be based upon using ALTER TABLE statements.