/
NestedSetsParentReference_operating_addnewnode.js
52 lines (44 loc) · 2.71 KB
/
NestedSetsParentReference_operating_addnewnode.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
use TreeMongo;
//assume, we want to add LG node under Electronics
//new node would have left value of 24, affecting all remaining left values according to traversal rules
// and will have right value of 25, affecting all remaining right values including root one.
//take next node in traversal tree
var followingsibling = db.categoriesNSO.findOne({_id:"Cell_Phones_and_Accessories"});
var previoussignling = db.categoriesNSO.findOne({_id:"Shop_Top_Products"});
var neworder = parseInt((followingsibling.order + previoussignling.order)/2);
//new node will have left value of the following sibling and right value - incremented by two following sibling's left one
var newnode = {_id:'LG', left:followingsibling.left,right:followingsibling.left+1, parent:followingsibling.parent, order:neworder};
//now we have to create the place for the new node
//update affects right values of all ancestor nodes
//3th and 4th parameters: false stands for upsert=false and true stands for multi=true
db.categoriesNSO.update({right:{$gt:followingsibling.right}},{$inc:{right:2}}, false, true)
//and affects all nodes that remain for traversal
db.categoriesNSO.update({left:{$gte:followingsibling.left}, right:{$lte:followingsibling.right}},{$inc:{left:2, right:2}}, false, true)
// ready to insert
db.categoriesNSO.insert(newnode)
exit
/*
+--Electronics (1,46) ord.[undefined]
+----Cameras_and_Photography (2,13) ord.[10]
+-------Digital_Cameras (3,4) ord.[10]
+-------Camcorders (5,6) ord.[20]
+-------Lenses_and_Filters (7,8) ord.[30]
+-------Tripods_and_supports (9,10) ord.[40]
+-------Lighting_and_studio (11,12) ord.[50]
+-----Shop_Top_Products (14,23) ord.[20]
+-------IPad (15,16) ord.[10]
+-------IPhone (17,18) ord.[20]
+-------IPod (19,20) ord.[30]
+-------Blackberry (21,22) ord.[40]
+-----LG (24,25) ord.[25]
+-----Cell_Phones_and_Accessories (26,45) ord.[30]
+-------Cell_Phones_and_Smartphones (27,38) ord.[10]
+----------Nokia (28,29) ord.[10]
+----------Samsung (30,31) ord.[20]
+----------Apple (32,33) ord.[30]
+----------HTC (34,35) ord.[40]
+----------Vyacheslav (36,37) ord.[50]
+--------Headsets (39,40) ord.[20]
+--------Batteries (41,42) ord.[30]
+--------Cables_And_Adapters (43,44) ord.[40]
*/