How to create a metadata that can store the difference between two versions of a JPA entity?

I am trying to create a metadata which can hold all differences between two versions of the same JPA entity.

This metadata is needed to create a migration DDL script for my store. What would be my metadata that could hold data for all migration scenario ?

for example

[
 {
"date": "9 may 2018, 6:06 pm",
"user": "user.name (FName LName)",
"JPAEntity":"Troll",
"actions": [
    "newColums":{
                 "name":"amount",
                 "type":"number"
                 }
]

This metadata says that for my JPA entity Troll, I have new column amount. Is there any Industry standard structure that is used for this purpose? I am looking for a metadata that could accommodate all conventional scenario of migration.

I tried with liquibase, but I can't go with it as I cannot provide my data store to it.