On same name, creating a RDB category would return the original one.

src/rdb/rdb/rdb.cc

@@ -881,6 +881,13 @@ Categories::category_by_name (const char *path)
   return 0;
 }
 
+Category *
+Categories::category_by_raw_name (const std::string &name)
+{
+  auto c = m_categories_by_name.find (name);
+  return c == m_categories_by_name.end () ? 0 : c->second;
+}
+
 void 
 Categories::import_category (Category *category)
 {
@@ -1353,6 +1360,11 @@ Database::create_category (const std::string &name)
 Category *
 Database::create_category (Categories *container, const std::string &name)
 {
+  Category *existing = container->category_by_raw_name (name);
+  if (existing) {
+    return existing;
+  }
+
   set_modified ();
 
   Category *cat = new Category (name);

src/rdb/rdb/rdb.h

@@ -413,8 +413,8 @@ class RDB_PUBLIC Categories
   }
 
   void add_category (Category *cath);
-
   void set_database (Database *database);
+  Category *category_by_raw_name (const std::string &name);
 };
 
 /**

testdata/python/rdbTest.py

@@ -952,6 +952,26 @@ def test_13(self):
     self.assertEqual(item1._is_const_object(), False)
     self.assertEqual(item1.has_tag(17), True)
 
+  def test_14(self):
+
+    # same names do not generate a new category
+    rdb = pya.ReportDatabase("")
+
+    _cell = rdb.create_cell("CELL")
+
+    _cat = rdb.create_category("cat")
+    _cat_same = rdb.create_category("cat")
+    self.assertEqual(_cat.rdb_id(), _cat_same.rdb_id())
+
+    _subcat = rdb.create_category(_cat, "subcat")
+    _subcat_same = rdb.create_category(_cat_same, "subcat")
+    self.assertEqual(_subcat.rdb_id(), _subcat_same.rdb_id())
+
+    # testing whether decrementing the reference count would do harm
+    _cat = None
+    _cat_same = None
+    self.assertEqual(_subcat.rdb_id(), _subcat_same.rdb_id())
+
 # run unit tests
 if __name__ == '__main__':
   suite = unittest.TestLoader().loadTestsFromTestCase(RDB_TestClass)

testdata/ruby/rdbTest.rb

@@ -1017,6 +1017,23 @@ def test_13
 
   end
 
+  def test_14
+
+    # same names do not generate a new category
+    rdb = RBA::ReportDatabase::new("")
+
+    _cell = rdb.create_cell("CELL")
+
+    _cat = rdb.create_category("cat")
+    _cat_same = rdb.create_category("cat")
+    assert_equal(_cat.rdb_id, _cat_same.rdb_id)
+
+    _subcat = rdb.create_category(_cat, "subcat")
+    _subcat_same = rdb.create_category(_cat_same, "subcat")
+    assert_equal(_subcat.rdb_id, _subcat_same.rdb_id)
+
+  end
+
 end
 
 load("test_epilogue.rb")