StackOverflow2013

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plurals

PO
primarykey
Id
8775601
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
3
CommunityOwnedDate
CreationDate
2012-01-08T05:27:27.483
FavoriteCount
0
LastActivityDate
2016-03-16T00:17:30.113
LastEditDate
2016-03-16T00:17:30.113
LastEditorUserId
1104885
OwnerUserId
1104885
ParentId
889527
PostTypeId
2
Score
13
ViewCount
0
LastEditorDisplayName
text
Body
Here is a solution that lets you move a node to any position in the tree, either as a sibling or a child with just a single input parameter - the new left position (newlpos) of the node. Fundamentally there are three steps: <ul> <li>Create new space for the subtree.</li> <li>Move the subtree into this space.</li> <li>Remove the old space vacated by the subtree.</li> </ul> In psuedo-sql, it looks like this: <pre><code>// * -- create new space for subtree * UPDATE tags SET lpos = lpos + :width WHERE lpos >= :newlpos * UPDATE tags SET rpos = rpos + :width WHERE rpos >= :newlpos * * -- move subtree into new space * UPDATE tags SET lpos = lpos + :distance, rpos = rpos + :distance * WHERE lpos >= :tmppos AND rpos < :tmppos + :width * * -- remove old space vacated by subtree * UPDATE tags SET lpos = lpos - :width WHERE lpos > :oldrpos * UPDATE tags SET rpos = rpos - :width WHERE rpos > :oldrpos */ </code></pre> The :distance variable is the distance between the new and old positions, the :width is the size of the subtree, and :tmppos is used to keep track of the subtree being moved during the updates. These variables are defined as: <pre><code>// calculate position adjustment variables int width = node.getRpos() - node.getLpos() + 1; int distance = newlpos - node.getLpos(); int tmppos = node.getLpos(); // backwards movement must account for new space if (distance < 0) { distance -= width; tmppos += width; } </code></pre> For a complete code example, see my blog at <a href="http://www.ninthavenue.com.au/how-to-move-a-node-in-nested-sets-with-sql" rel="noreferrer">http://www.ninthavenue.com.au/how-to-move-a-node-in-nested-sets-with-sql</a> If you like this solution, please up-vote.
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PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. POMove node in nested set
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 PostTypePostTypeId
 PTQuestion
PostTypePostTypeId
1. PTAnswer
UserLastEditorUserId
1. USRoger Keays
UserOwnerUserId
1. USRoger Keays
plurals
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1. This table or related slice is empty.
PostsAcceptedAnswerId
1. This table or related slice is empty.
PostsParentIdCreationDate
1. This table or related slice is empty.
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1. VO
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 This table or related slice is empty.
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2. VO
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CommentsPostId
1. COwhat is the newpos? is it old lpos or rpos? what is it exactly?
 singulars
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 PO
 UserUserId
 USArash Mousavi

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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.

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