text: CREATE TABLE dummy_entity
  (
      id   BIGINT GENERATED BY DEFAULT AS IDENTITY ( START WITH 1 ) PRIMARY KEY,
      NAME VARCHAR(100)
  );
  CREATE TABLE element
  (
      id               BIGINT GENERATED BY DEFAULT AS IDENTITY (START WITH 1) PRIMARY KEY,
      content          VARCHAR(100),
      Dummy_Entity_key BIGINT,
      dummy_entity     BIGINT
  );
  
  CREATE TABLE root
  (
      id BIGINT GENERATED BY DEFAULT AS IDENTITY ( START WITH 1 ) PRIMARY KEY
  );
  CREATE TABLE intermediate
  (
      id       BIGINT GENERATED BY DEFAULT AS IDENTITY ( START WITH 1 ) PRIMARY KEY,
      root     BIGINT  NOT NULL,
      root_key INTEGER NOT NULL
  );
  CREATE TABLE leaf
  (
      name             VARCHAR(100),
      intermediate     BIGINT  NOT NULL,
      intermediate_key INTEGER NOT NULL
  );
  