BI-2779 - Observation levels data migration

src/main/resources/db/migration/V005.002__migrate_observation_levels.sql

@@ -0,0 +1,116 @@
+-- Create new observation level names for each unique observationLevel in
+-- the additional_info column of the observation_unit table
+--
+-- Assumption: all observation_unit.program_id have ids which is true for our
+-- usage. Database allows NULLs but we don't have to handle that
+--
+-- * The level order will be 0 for all of these indicating Exp Unit
+-- * All level names should be converted to lower case and combined
+--   in the case of different cases to reference the same level
+-- * Level names should be created for the program the observation unit is in, not globally
+INSERT INTO observation_unit_level_name (level_name, level_order, program_id)
+SELECT DISTINCT
+    lower(btrim(ou.additional_info ->> 'observationLevel')) AS level_name,
+    0 AS level_order,
+    ou.program_id
+FROM observation_unit ou
+WHERE NULLIF(btrim(ou.additional_info ->> 'observationLevel'), '') IS NOT NULL
+  AND ou.program_id IS NOT NULL
+    ON CONFLICT (level_name, program_id) DO NOTHING;
+-- on conflict only relevant for test servers, won't have conflicts on prod because
+-- no additional observationlevelnames have been created other than global defaults from migration
+
+-- Update global level references to newly created program scoped levels
+-- For prod, these will be:
+-- * plot
+-- * plant
+-- * fish
+-- * bine
+-- * tree
+-- There will be multiple instances as some levels are reused in different programs
+--
+-- Need to handle observation_unit_position, but can skip & observation_unit_level and
+-- study_observation_level. bi-api has never written study_observation_level and no records exist
+-- in prod. observation_unit_level only has rep and block global references and those were already
+-- updated in a previous migration.
+
+-- Updates observation_unit_position.level_name to point to the program-scoped
+-- observation_unit_level_name record that matches the observation unit's
+-- additional_info.observationLevel value.
+--
+-- Only updates rows where:
+-- * additional_info.observationLevel is present and not blank
+-- * observation_unit.program_id is present
+-- * the current linked level is null or does not already match the target
+--   * some data like tree will point to plot due to how old data was written and will be fixed by this
+--   * some data has null levels due to how it was written and will be fixed by this
+WITH rows_to_update AS (
+    SELECT
+        oup.id AS observation_unit_position_id,
+        target.id AS target_level_id
+    FROM observation_unit_position oup
+             JOIN observation_unit ou
+                  ON ou.id = oup.observation_unit_id
+             JOIN observation_unit_level_name target
+                  ON target.program_id = ou.program_id
+                      AND target.level_name = lower(btrim(ou.additional_info ->> 'observationLevel'))
+    WHERE NULLIF(btrim(ou.additional_info ->> 'observationLevel'), '') IS NOT NULL
+      AND ou.program_id IS NOT NULL
+      AND oup.level_name IS DISTINCT FROM target.id
+    )
+UPDATE observation_unit_position oup
+SET level_name = rows_to_update.target_level_id
+    FROM rows_to_update
+WHERE oup.id = rows_to_update.observation_unit_position_id;
+
+-- Assertion to assure we don't remove additional_info.observationLevel where
+-- references can't be updated. For our prod data, shouldn't be any.
+DO $$
+BEGIN
+    IF EXISTS (
+        SELECT 1
+        FROM observation_unit ou
+        WHERE NULLIF(btrim(ou.additional_info ->> 'observationLevel'), '') IS NOT NULL
+            AND (
+                ou.program_id IS NULL
+                OR NOT EXISTS (
+                    SELECT 1
+                    FROM observation_unit_level_name ouln
+                    WHERE ouln.program_id = ou.program_id
+                        AND ouln.level_name = lower(btrim(ou.additional_info ->> 'observationLevel'))
+                )
+            )
+    ) THEN
+    RAISE EXCEPTION
+          'V005.002 cannot remove observationLevel from observation_unit.additional_info because some rows could not be
+    mapped';
+END IF;
+END $$;
+
+-- Remove observationLevel from additional_info in observation_unit table as it is no longer needed
+UPDATE observation_unit
+SET additional_info = additional_info - 'observationLevel';
+
+-- Remove unused global level names (will exclude rep & block). On prod, these will be removed:
+-- * entry
+-- * field
+-- * pot
+-- * sample
+-- * study
+-- * sub-block
+-- * sub-plot
+-- Level is unused if not referenced in tables:
+-- * observation_unit_position
+-- * observation_unit_level
+-- * study_observation_level has no existing data in prod but included
+DELETE FROM observation_unit_level_name ouln
+WHERE ouln.program_id IS NULL
+    AND NOT EXISTS (
+        SELECT 1 FROM observation_unit_position oup WHERE oup.level_name = ouln.id
+    )
+    AND NOT EXISTS (
+        SELECT 1 FROM observation_unit_level oul WHERE oul.level_name = ouln.id
+    )
+    AND NOT EXISTS (
+        SELECT 1 FROM study_observation_level sol WHERE sol.level_name = ouln.id
+    );