If you have A -> B -> A, what do you expect your table to look like? I don't think that using sequential IDs will work that well ...
 

Table A

a_id | b_id
-----------
1      1


Table B

b_id | a_id
-----------
1      1

[download]

Each table has its own pool of sequential IDs, like most databases.

If, however, you are using three tables (One for nodes, one for linktypes, and one for node/node/link), then this is trivial:

Nope, it's not that simple. Each node type has its own table structure and most of them are more complicated than that.

-sam

In reply to Re^2: In search of an algorithm for loading cyclic graphs by samtregar
in thread In search of an algorithm for loading cyclic graphs by samtregar

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.