Signature matching

migration/ids_signature.7.cr

@@ -0,0 +1,50 @@
+class IDSignature < MG::Base
+  def up : String
+    <<-SQL
+    ALTER TABLE ids ADD COLUMN signature TEXT;
+    SQL
+  end
+
+  def down : String
+    <<-SQL
+    -- remove signature column from ids
+    ALTER TABLE ids RENAME TO tmp;
+
+    CREATE TABLE ids (
+      path TEXT NOT NULL,
+      id TEXT NOT NULL
+    );
+
+    INSERT INTO ids
+    SELECT path, id
+    FROM tmp;
+
+    DROP TABLE tmp;
+
+    -- recreate the indices
+    CREATE UNIQUE INDEX path_idx ON ids (path);
+    CREATE UNIQUE INDEX id_idx ON ids (id);
+
+    -- recreate the foreign key constraint on thumbnails
+    ALTER TABLE thumbnails RENAME TO tmp;
+
+    CREATE TABLE thumbnails (
+      id TEXT NOT NULL,
+      data BLOB NOT NULL,
+      filename TEXT NOT NULL,
+      mime TEXT NOT NULL,
+      size INTEGER NOT NULL,
+      FOREIGN KEY (id) REFERENCES ids (id)
+        ON UPDATE CASCADE
+        ON DELETE CASCADE
+    );
+
+    INSERT INTO thumbnails
+    SELECT * FROM tmp;
+
+    DROP TABLE tmp;
+
+    CREATE UNIQUE INDEX tn_index ON thumbnails (id);
+    SQL
+  end
+end