Database changes

How does Echo handle changes to the database structure?

For example, I have an application that has not been synchronized in a long time.

Columns were excluded, others were added and in others the data type was modified.

What will happen in the synchronization?

Internal data in echo is JSON, and it holds information about data it needs. For example, if you update a record, it holds, in JSON, the list of modified columns and their values.

When replicated, it will simply try to apply those changes to the target database. If some of those columns were removed or renamed, you will get an error. 

A small correction: the JSON holds the names of "mapped class members", not "columns". In other words, it deserialize that JSON in an Aurelius object, then it will persist that Aurelius object.

That means the columns and tables it will apply the modifications to depends on the mapping on the Aurelius entity. You can modify the mapping to target the changes to a different column/table than the original one. But then it's up to you to track those modifications.