Databases
StackOverflow2013
Postsdbo
POTree traversal with page property sortIndex
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POTree traversal with page property sortIndex
    primarykey
    data
    text
    <p>I'm building a tree structure based on a list retrieved from a <code>db.Model</code> called Pages. </p> <p>Each Page entry has a parentKey property that's a <code>db.SelfReferenceProperty()</code> and a <code>db.IntegerProperty()</code> called sortIndex.</p> <p>I fetch the list and call a method to travers over the list and make a nestled dict as my tree. The reason I fetch the entire list is that I want to skip multiple queries. </p> <pre><code>pages = Pages.gql('ORDER BY sortIndex').fetch(1000) build_tree(pages) </code></pre> <p>And the build_tree:</p> <pre><code>def build_tree(nodes, *args): # create empty tree to fill tree = {} build_tree_recursive(tree, None, nodes, *args) return tree def build_tree_recursive(tree, parent, nodes, *args): # find root children, first level nodes have no parentKey if parent is None: children = [n for n in nodes if n.parentKey == None] # find children else: children = [n for n in nodes if n.parentKey is not None and n.parentKey.key() == parent] # build a subtree for each child for child in children: # start new subtree key = child.key() # Use page entry key as unique dict key tree[key] = { 'page' : child, 'children' : {}} # call recursively to build a subtree for current node build_tree_recursive(tree[key]['children'], key, nodes) </code></pre> <p>The problem is that the list get's rearranged and don't follow det ORDER BY. I think this is due to that each Page is put in the list when a proper parent is found. But even the first level (Pages that has <code>parentKey == None</code>) get's returned in the wrong order.</p> <p>I've tried setting a prefix using a loop counter on tree[str(i) + '_' + str(key)] but still didn't return in a proper order.</p> <p>So the question how to get them in an proper order?</p> <p><strong>EDIT [Solved]:</strong></p> <p>See below</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USfredrik
    1. USfredrik
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POTree traversal with page property sortIndex
      1. USneoneye
      1. VTFavorite
    2. VO
      singulars
      1. POTree traversal with page property sortIndex
      1. This table or related slice is empty.
      1. VTUpMod
    1. COBe aware that you're not saving on queries here - every time you do 'n.parentkey' for the first time on an entity, it fetches the entity from the datastore.
      singulars
      1. POTree traversal with page property sortIndex
      1. USNick Johnson
    2. COThanks. I been working on this for the last couple of hours and indeed noticed it. Any ideas of how to get around it? I think I read somewhere that one can pre-catch some data?
      singulars
      1. POTree traversal with page property sortIndex
      1. USfredrik
    3. CO@fredrik: if you had answered your own question instead of editing it (possible even marking it as accepted) others would not find your question again and again, when searching for old, unanswered, questions.
      singulars
      1. POTree traversal with page property sortIndex
      1. USAnthon
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload