[Zope] Tree hierarchy problem with database

[juangar@dei.inf.uc3m.es]

Hi,

My tables in the database (PostgreSQL 7) are:

CREATE TABLE cod_recurso (
  codigo_recurso      VARCHAR(20) NOT NULL PRIMARY KEY
);

CREATE TABLE recurso (
  codigo_recurso      VARCHAR(20) NOT NULL,
  idioma              VARCHAR(10) NOT NULL,
  termino             VARCHAR(50) NOT NULL,
  CONSTRAINT pk_recurso
    PRIMARY KEY (codigo_recurso, idioma),
  CONSTRAINT existe_idioma
    FOREIGN KEY (idioma) REFERENCES idioma
    ON DELETE RESTRICT,
  CONSTRAINT existe_codigo_recurso
    FOREIGN KEY (codigo_recurso) REFERENCES cod_recurso
    ON DELETE CASCADE
);

CREATE TABLE relaciones_recursos (
  codigo_recurso1     VARCHAR(20) NOT NULL,
  codigo_recurso2     VARCHAR(20) NOT NULL,
  relacion            VARCHAR(10) DEFAULT 'NT',
  CONSTRAINT pk_relaciones_recursos
    PRIMARY KEY (codigo_recurso1, codigo_recurso2),
  CONSTRAINT existe_recurso1
    FOREIGN KEY (codigo_recurso1) REFERENCES cod_recurso
    ON DELETE CASCADE,
  CONSTRAINT existe_recurso2
    FOREIGN KEY (codigo_recurso2) REFERENCES cod_recurso
    ON DELETE CASCADE
);

Where the last one is where i have the hierarchy with data like this:

 codigo_recurso1 | codigo_recurso2 | relacion
   1.            -   1.1.          -   NT
   1.            -   1.2.          -   NT
   1.1.          -   1.1.1.        -   NT
   1.1.          -   1.1.2.        -   NT
   1.1.1.        -   1.1.1.1       -   NT
   2.            -   2.1.          -   NT
   3.            -   3.1.          -   NT

I have a query that returns the direct childs of each code, and this one
is what i use en the tree tag (branches_expr).
With this data i want to show the next tree:

  + 1.
    + 1.1.
      + 1.1.1.
        + 1.1.1.1.
      + 1.1.2.
    + 1.2.
  + 2.
    + 2.1.
  + 3.
    + 3.1.

Is it posible with the tree tag?

Thank you. Bye.