Styjun

I'm missing the clarity of how to handle SQLite database migration when the user doesn't want to update the app which includes additional columns for the updated app. How to handle the crash and the issues which occur when the user doesn't want to update the app. Any suggestions will be appreciable.

I have tried the following code which includes the Upgrading the database version though when user doesn't want to update the app.

Like the below in on upgrade method

 @Override
 public void onUpgrade(SQLiteDatabase db, int oldVersion, int 
 newVersion) 
 switch (oldVersion)
 case 1:
 db.execSQL("ALTER TABLE " + TABLE_GITHUB + " ADD COLUMN " + 
 NODE_ID + " TEXT ");

 case 2:
 db.execSQL("ALTER TABLE " + TABLE_GITHUB + " ADD COLUMN " + 
 PRIVATE + " TEXT ");

 case 3:
 db.execSQL("ALTER TABLE GITHUB_DATA ADD COLUMN repos_url 
 text");
 

I was successful in upgrading the SQLite database when the user has SQLite version 2 and made it as 3 by using the above on the upgrade method. But I have failed of getting the data from which the column I added (of repos_url column). The column has been added to the SQLite but I was unable to get the data though I have data from the server. Any suggestion will be appreciable. Thank you.

Edit:
Considering this situation If I'm maintaining the versioning using the server.

I have repos_url which i need to include for the new version user.This is the adapter i need to show in recyclerview.

@Override
public void onBindViewHolder(@NonNull GithubViewHolder githubViewHolder, int i) 

 HashMap<String,String> hashMap = githubArryaList.get(i);

 githubViewHolder.name.setText(hashMap.get("name"));
 githubViewHolder.fullname.setText(hashMap.get("full_name"));
 githubViewHolder.id.setText(hashMap.get("id"));
 githubViewHolder.node_id.setText(hashMap.get("node_id"));
 githubViewHolder.priv.setText(hashMap.get("private"));

 //new column
 githubViewHolder.repos_url.setText(hashMap.get("repos_url"));

And this is the sqlite method for sending the data.

public ArrayList getFavouritesData()

 ArrayList arrayList = new ArrayList();
 SQLiteDatabase db = this.getReadableDatabase();
 Cursor cursor = db.rawQuery("SELECT * FROM " + TABLE_GITHUB,null);

 if (cursor.moveToFirst())

 do 

 HashMap<String,String> hashMap = new HashMap<>();
 hashMap.put(SqliteFavouriteDatabase.NAME,cursor.getString(cursor.getColumnIndex(SqliteFavouriteDatabase.NAME)));
 hashMap.put(SqliteFavouriteDatabase.FULL_NAME,cursor.getString(cursor.getColumnIndex(SqliteFavouriteDatabase.FULL_NAME)));
 hashMap.put(SqliteFavouriteDatabase.ID,cursor.getString(cursor.getColumnIndex(SqliteFavouriteDatabase.ID)));
 hashMap.put(SqliteFavouriteDatabase.NODE_ID,cursor.getString(cursor.getColumnIndex(SqliteFavouriteDatabase.NODE_ID)));
 hashMap.put(SqliteFavouriteDatabase.PRIVATE,cursor.getString(cursor.getColumnIndex(SqliteFavouriteDatabase.PRIVATE)));
 hashMap.put(SqliteFavouriteDatabase.REPOS_URL,cursor.getString(cursor.getColumnIndex(SqliteFavouriteDatabase.REPOS_URL)));


 arrayList.add(hashMap);

 while (cursor.moveToNext());
 
 cursor.close();
 db.close();
 return arrayList;

The question is for the oldd version how to handle the new column data.The issue arise when there is no column called repos_url for the old version but I have to use the repos_url for the new user and i have to use the same method and adapter for both versions (new and old).How to handle this for both versions. Thank you

That is backward compatibility -- your new server is not compatible with old version of app.

While it is impossible (or difficult) to modify old version of app, you can make change in both new version of app and new version of server to handle this:

1. in new version of app, when request raised to server, add extra information to indicate this is from new version of app


2. in new version of server, when receive request from app, check if extra information is available


3. if extra information is available, it is from new version of app, you can add new columns in the response


4. if extra information is not available, it is from old version of app, you should remove new column in the response


5. new version of app will receive new columns and handle


6. old version of app will receive response without new column, and is able to handle.