Replace mod_logs columns with a table - for real! #2615
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https://eaflood.atlassian.net/browse/WATER-4563 https://eaflood.atlassian.net/browse/WATER-4564 https://eaflood.atlassian.net/browse/WATER-4565 > We foolishly merged [Replace mod_logs columns with a table](#2613) as an empty commit hence doing it for real this time! > Part of the work to display a licence's history to users (mod log) **It's a trap!** We have made the same mistake as the previous team. When we believed that a version (charge, licence, or return) had a one-to-one relationship with NALD mod log records, a JSONB field in each was a suitable solution to capturing just the information we needed. After all, it's only the historical records we have to worry about. But when we learned that a version record could be linked to multiple mod logs, we should have taken a different approach. Instead, we ploughed on with our JSON column [altering its name and default](#2612) to match. 🤦😬 Once you've started down the JSONB road, it is easy to get trapped! Thankfully, we've come to our senses before this saw the light of day in production. The mod log data we are importing needs to go into its own table, and we will link our version records accordingly. A 'standard' relationship database solution. We could just add a migration that drops the columns and adds the new table. But because of the interaction between the views [water-abstraction-system](https://github.com/DEFRA/water-abstraction-system) creates, it's no longer possible. Because the mod log column migrations have not been run in production yet, we're just going to delete them. This might be a bit messy for our local environments, but it avoids leaving a 'dead' field in the database. So, in this change, we delete the old migrations and then add our new table migration.
Works locally built not in CI without these fixes.
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https://eaflood.atlassian.net/browse/WATER-4563
https://eaflood.atlassian.net/browse/WATER-4564
https://eaflood.atlassian.net/browse/WATER-4565
It's a trap!
We have made the same mistake as the previous team. When we believed that a version (charge, licence, or return) had a one-to-one relationship with NALD mod log records, a JSONB field in each was a suitable solution to capturing just the information we needed. After all, it's only the historical records we have to worry about.
But when we learned that a version record could be linked to multiple mod logs, we should have taken a different approach. Instead, we ploughed on with our JSON column altering its name and default to match. 🤦😬
Once you've started down the JSONB road, it is easy to get trapped!
Thankfully, we've come to our senses before this saw the light of day in production. The mod log data we are importing needs to go into its own table, and we will link our version records accordingly. A 'standard' relationship database solution.
We could just add a migration that drops the columns and adds the new table. But because of the interaction between the views water-abstraction-system creates, it's no longer possible.
Because the mod log column migrations have not been run in production yet, we're just going to delete them. This might be a bit messy for our local environments, but it avoids leaving a 'dead' field in the database.
So, in this change, we delete the old migrations and then add our new table migration.