106798 workspaceitem table migration: delete duplicate rows before in…

…troducing uniqueness constraint

dspace-api/src/main/resources/org/dspace/storage/rdbms/sqlmigration/h2/V7.6_2024.12.17__workspaceitem_add_item_id_unique_constraint.sql

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+--
+-- The contents of this file are subject to the license and copyright
+-- detailed in the LICENSE and NOTICE files at the root of the source
+-- tree and available online at
+--
+-- http://www.dspace.org/license/
+--
+
+-- In the workspaceitem table, if there are multiple rows referring to the same item ID, keep only the first of them.
+WITH dedup AS (
+    SELECT item_id, MIN(workspace_item_id) AS workspace_item_id
+    FROM workspaceitem
+    GROUP BY item_id
+    HAVING COUNT(workspace_item_id) > 1
+)
+DELETE FROM workspaceitem
+    USING dedup
+WHERE workspaceitem.item_id = dedup.item_id AND workspaceitem.workspace_item_id <> dedup.workspace_item_id;
+
+-- Identify which rows have duplicates, and compute their replacements.
+ALTER TABLE workspaceitem ADD CONSTRAINT unique_item_id UNIQUE(item_id);

dspace-api/src/main/resources/org/dspace/storage/rdbms/sqlmigration/postgres/V7.6_2024.12.17__workspaceitem_add_item_id_unique_constraint.sql

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+--
+-- The contents of this file are subject to the license and copyright
+-- detailed in the LICENSE and NOTICE files at the root of the source
+-- tree and available online at
+--
+-- http://www.dspace.org/license/
+--
+
+-- In the workspaceitem table, if there are multiple rows referring to the same item ID, keep only the first of them.
+WITH dedup AS (
+    SELECT item_id, MIN(workspace_item_id) AS workspace_item_id
+    FROM workspaceitem
+    GROUP BY item_id
+    HAVING COUNT(workspace_item_id) > 1
+)
+DELETE FROM workspaceitem
+USING dedup
+WHERE workspaceitem.item_id = dedup.item_id AND workspaceitem.workspace_item_id <> dedup.workspace_item_id;
+
+-- Enforce uniqueness of item_id in workspaceitem table.
+ALTER TABLE workspaceitem ADD CONSTRAINT unique_item_id UNIQUE(item_id);