db: split schema into separate files

src/lib/db/schema/tables/artist-alt-names.ts

@@ -0,0 +1,55 @@
+import {
+	index,
+	integer,
+	sqliteTable,
+	text,
+	uniqueIndex,
+} from "drizzle-orm/sqlite-core";
+import { artistsTable } from "./artists";
+
+/**
+ * Alternative names for artists.
+ *
+ * Source: AmqArtistSchema.altNames
+ *
+ * Interpreted as: artist `songArtistId` is also known as `name` (optionally via altSongArtistId link).
+ */
+export const artistAltNamesTable = sqliteTable(
+	"artist_alt_names",
+	{
+		id: integer("id").notNull().primaryKey({ autoIncrement: true }),
+
+		/**
+		 * The "owning" artist.
+		 */
+		songArtistId: integer("song_artist_id")
+			.notNull()
+			.references(() => artistsTable.songArtistId, {
+				onDelete: "cascade",
+			}),
+
+		/**
+		 * The alternate-name entry is keyed by an artist id in the source:
+		 * { songArtistId, name }
+		 *
+		 * Store as a linked artist row for referential integrity.
+		 */
+		altSongArtistId: integer("alt_song_artist_id")
+			.notNull()
+			.references(() => artistsTable.songArtistId, {
+				onDelete: "cascade",
+			}),
+
+		name: text("name").notNull(),
+	},
+	(t) => ({
+		artistIndex: index("artist_alt_names_artist_id_idx").on(t.songArtistId),
+		altArtistIndex: index("artist_alt_names_alt_artist_id_idx").on(
+			t.altSongArtistId,
+		),
+		nameIndex: index("artist_alt_names_name_idx").on(t.name),
+		uniquePerArtistAltArtistName: uniqueIndex(
+			"artist_alt_names_artist_alt_artist_name_uq",
+		).on(t.songArtistId, t.altSongArtistId, t.name),
+	}),
+);