Use trigger instead of fk to avoid redundant deletion

mobile/lib/db/local/db.dart

@@ -12,7 +12,7 @@ import "package:photos/log/devlog.dart";
 import "package:sqlite_async/sqlite_async.dart";
 
 class LocalDB with SqlDbBase {
-  static const _databaseName = "local_2.db";
+  static const _databaseName = "local_3.db";
   static const _batchInsertMaxCount = 1000;
   static const _smallTableBatchInsertMaxCount = 5000;
   late final SqliteDatabase _sqliteDB;
@@ -101,7 +101,7 @@ class LocalDB with SqlDbBase {
         );
       }
     });
-  
+
     debugPrint(
       '$runtimeType insertPathToAssetIDs $pairCount complete in '
       '${stopwatch.elapsed.inMilliseconds}ms for '

mobile/lib/db/local/schema.dart

@@ -30,25 +30,38 @@ class LocalDBMigration {
     ''',
     '''
     CREATE TABLE metadata (
-      id TEXT PRIMARY_KEY,
+      id TEXT PRIMARY KEY,
       hash TEXT NOT NULL,
       created_at INTEGER NOT NULL,
       modified_at INTEGER NOT NULL,
       latitude REAL,
-      longitude REAL,
-      PRIMARY KEY (id),
-      FOREIGN KEY (id) REFERENCES assets (id) ON DELETE CASCADE
+      longitude REAL
     );
     ''',
     '''
+    CREATE TRIGGER delete_metadata
+    AFTER DELETE ON assets
+    FOR EACH ROW
+    BEGIN
+        DELETE FROM metadata WHERE id = OLD.id;
+    END;
+    ''',
+    '''
     CREATE TABLE old_hash (
      id TEXT NOT NULL,
      hash TEXT NOT NULL,
      created_at INTEGER NOT NULL,
-     PRIMARY KEY (id, hash),
-     FOREIGN KEY (id) REFERENCES assets (id) ON DELETE CASCADE
+     PRIMARY KEY (id, hash)
     ); 
-  ''',
+    ''',
+    '''
+    CREATE TRIGGER delete_old_hash
+    AFTER DELETE ON assets
+    FOR EACH ROW
+    BEGIN
+        DELETE FROM old_hash WHERE id = OLD.id;
+    END;
+    ''',
     '''
     CREATE TRIGGER update_old_hash
     AFTER UPDATE OF hash ON metadata
@@ -72,18 +85,31 @@ class LocalDBMigration {
     CREATE TABLE device_path_assets (
       path_id TEXT NOT NULL,
       asset_id TEXT NOT NULL,
-      PRIMARY KEY (path_id, asset_id),
-      FOREIGN KEY (path_id) REFERENCES device_path (path_id) ON DELETE CASCADE,
-      FOREIGN KEY (asset_id) REFERENCES assets (id) ON DELETE CASCADE
+      PRIMARY KEY (path_id, asset_id)
     );
     ''',
     '''
+    CREATE TRIGGER delete_device_path_assets
+    AFTER DELETE ON assets
+    FOR EACH ROW
+    BEGIN
+        DELETE FROM device_path_assets WHERE asset_id = OLD.id;
+    END;
+    ''',
+    '''
     CREATE TABLE queue (
       id TEXT NOT NULL,
       name TEXT NOT NULL,
-      PRIMARY KEY (id, name),
-      FOREIGN KEY (id) REFERENCES assets (id) ON DELETE CASCADE
-    )
+      PRIMARY KEY (id, name)
+    );
+    ''',
+    '''
+    CREATE TRIGGER delete_queue
+    AFTER DELETE ON assets
+    FOR EACH ROW
+    BEGIN
+        DELETE FROM queue WHERE id = OLD.id;
+    END;
     ''',
   ];