CategoryDB createCategoryDB(CategoryDB parent, String categoryName) throws IOException {
		CategoryDB c = parent.getCategory(categoryName);
		if (c != null) {
			return c;
		}
		DBRecord rec = categoryAdapter.createCategory(categoryName, parent.getKey());
		String name = rec.getString(CategoryDBAdapter.CATEGORY_NAME_COL);
		CategoryDB cat = new CategoryDB(this, catCache, rec.getKey(), parent, name);
		parent.categoryAdded(cat);// must be before the event notification below
		categoryCreated(cat);
		return cat;
	}
This method should be invoked following an undo/redo or a transaction rollback situation.
This will notify {@link DataTypeManagerChangeListenerHandler} and its listeners that this 
manager has just been restored (e.g., undo/redo/rollback).
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/data/DataTypeManagerDB.java