feat: add topic hierarchy APIs

src/core/migrations.ts

@@ -3,6 +3,7 @@ import type { Kysely } from 'kysely';
 import {
   FACTS_TABLE,
   FACT_TOPICS_TABLE,
+  TOPIC_RELATIONS_TABLE,
   TOPICS_TABLE,
 } from './schema';
 import type { IdentityDatabaseSchema } from '../types/database';
@@ -52,6 +53,20 @@ export async function initializeSchema(
     .addPrimaryKeyConstraint('fact_topics_pk', ['fact_id', 'topic_id', 'position'])
     .execute();
 
+  await db.schema
+    .createTable(TOPIC_RELATIONS_TABLE)
+    .ifNotExists()
+    .addColumn('parent_topic_id', 'text', (column) =>
+      column.notNull().references(`${TOPICS_TABLE}.id`).onDelete('cascade'),
+    )
+    .addColumn('child_topic_id', 'text', (column) =>
+      column.notNull().references(`${TOPICS_TABLE}.id`).onDelete('cascade'),
+    )
+    .addColumn('relation', 'text', (column) => column.notNull())
+    .addColumn('created_at', 'text', (column) => column.notNull())
+    .addPrimaryKeyConstraint('topic_relations_pk', ['parent_topic_id', 'child_topic_id', 'relation'])
+    .execute();
+
   await db.schema
     .createIndex('fact_topics_topic_id_idx')
     .ifNotExists()
@@ -65,4 +80,18 @@ export async function initializeSchema(
     .on(FACT_TOPICS_TABLE)
     .column('fact_id')
     .execute();
+
+  await db.schema
+    .createIndex('topic_relations_parent_topic_id_idx')
+    .ifNotExists()
+    .on(TOPIC_RELATIONS_TABLE)
+    .column('parent_topic_id')
+    .execute();
+
+  await db.schema
+    .createIndex('topic_relations_child_topic_id_idx')
+    .ifNotExists()
+    .on(TOPIC_RELATIONS_TABLE)
+    .column('child_topic_id')
+    .execute();
 }