How to manage database version in REST API

Question

Suppose I have an mobile app named APPO v1 which take resources from a REST API v1. There are about thousands of user at APPO v1 Now I am developing APPO v2 with API v2. Both api and app have new functionality and new fields in database. Some fields are modified too.

API v1 DATABASE SCHEMA:

{
  "user_id": NumberLong(616),
  "name": "XYZ",
  "city":"Dhaka"
  "password": "raw password: 12345678",
  "gender": ""
}

API v2 DATABASE SCHEMA:

{
  "user_id": "STRING HASH",
  "name": "XYZ",
  "address":"98/3 Circle road, Dhaka 1209"
  "password": "MD5 HASH",
  "NEW_FIELD": NumberLong(5)
  "ANOTHER_FIELD": ""
}

Changes:

1. data type of user id is changed
2. Short city name replaced with address string
3. password format is changed
4. gender field is removed
5. some new field is added

How to handle the database ?

My solution 1: Separate DB by v1 & v2. Re-format the v1 and paste into v2

Problem with solution 1: All user will not update the app in a day. If a v1 user update their app to v2 they may loose the recent data. I have to make a synchronizer between two DB

My Solution 2: Since my app v1 takes raw password I have to keep this right away. I should marge the both SCHEMA

{
  "user_id": NumberLong(616),
  "user_id_hash": "STRING HASH",
  "name": "XYZ",
  "city":"Dhaka"
  "address":"98/3 Circle road, Dhaka 1209"
  "password": "raw password: 12345678"
  "password_md5": "MD5 FORMAT",
  "gender": ""
  "NEW_FIELD": NumberLong(5)
  "ANOTHER_FIELD": ""
}

Problem with solution 2: It will create huge garbage when the version will greater than 10 or more. At v10 i dont need v6,v5.......v1 Data

NOTE: Fields have nothing to do with REST model. All are example fields for such kind of situation

I am totally confused how to deal with that. I really appreciate your patient and your suggestion! Thanks in advance !

Answer 1

i have a solution, if you don't want to denormalize the database. You can use bridge pattern for this problem. When you have same type of multiple problems/implementations(API v1 & API v2...etc), but client will be connected with only one implementation (ex. API v1 ), you need to implement a bridge object, which will understand, where to place the client, i mean required implementation. in technically, you have to write the business logic for each problem separately but only one REST Api is enough to redirect the client to that implementation. Thanks