Question

In Drupal, if you want to insert something into the node table, ‘nid’ can be null, but ‘vid’ can’t. The inverse is true for the node_revision table.

In which order are nodes inserted when they are created?

I can’t insert into the node table, because I don’t have the revision ID; I can’t insert into the node_revision table, because I don’t have a node ID.

Also, is there some kind of function available that can easily do this insert for you?

Answer 1

The code of the node_save function is available ; did you try to see how it’s working ?

Here’s the part that relates to node creation :

if ($node->is_new) {
  _node_save_revision($node, $user->uid);
  drupal_write_record('node', $node);
  db_query('UPDATE {node_revisions} SET nid = %d WHERE vid = %d', $node->nid, $node->vid);
  $op = 'insert';
}

Apparently, it first saves the revision of the node, and, only then, saves the node itself.

After that, the node_revisions record is updated, to put the value of the nid.

If you want t save a node, you shouldn’t write code that would do that for you : you just have to call node_save, and it’ll save the node, call the required hooks, and all that.