The database - adding persistence to our data

Everything we have discussed until this point has been stateless. If we want to make use of data from another point in time or from other systems in a centralized way, we need to add a database.

By adding persistence, we add a lot of value to our application:

• We can now view values from the past
• We can now show changes in values rather than just the values themselves
• We can now store data from multiple sensors and view them together