What is the best way for applications to work with shared data in a database?

Question

Database

Greetings!

I am developing 3 applications which are part of the same project.
What is the best way to organize data storage, provided that each application must have access to data that other applications store?
The amount of data is small.
- Each application should have its own database that other applications can access?
- Or is it better to make 1 database server where applications will go?
- Or is it better to set up copying the necessary data from one database to another?

Answer 1

When multiple applications access the same DBMS, it becomes more difficult to support these applications:

• you have to change the code in all applications for any changes in the DBMS schema
  
• you need to track how changes affect other applications due to possible regression.
  
• monitor connections and how requests from one application affect others (timeout, deadlock).
  

If all applications must write to the same database, then it is better to add a layer to access it.
DB <= service A
service A <= service B
service A <= service C
In addition, it will be easier to manage, debug and scale if needed. The area of ​​responsibility will be at one service.