[sklivvz1971]

All the schema changes are applied to all site databases at the same time. They need to be backwards compatible so, for example, if you need to rename a column - a worst case scenario - it's a multiple steps process: add a new column, add code which works with both columns, back fill the new column, change code so it works with the new column only, remove the old column.

[avemg]

Thanks for the reply. We have a similar architecture where I work so this is interesting to me. A couple more questions if you don't mind:

- Do you use any tools for orchestrating the rollout of those schema changes or do you just have some homegrown scripts?

- Do you separate your schema versioning and deployment process from your application versioning and deployment process?

- How do you handle cases where backwards-compatibility is not possible? For example, a new application feature that depends on a brand new table.