Calculation of Treegrid Record Properties LfT and RGT in Jqgrid

These two properties are important when calculating a multilevel record, with the following specific rules:

Records A and record e are first-level nodes, B, C is a child node, D is a child of C, and F is a child of E.

Starting from record A, the lft of a is 1, recursively reads all the child nodes of a, and the order is lft assigned. If there are child nodes in the child node (such as C), then continue to traverse the assignment, and when all child node traversal is complete, the order is returned, assigning a value to each node's RGT.

The assignment order for a node is: A (LFT)->b (LFT)->b (RGT)->c (LFT)->d (LFT)->d (RGT)->c (RGT)->a (RGT), the assignment of node E is the same as a

-A lft:1 Rgt:8

-B lft:2 Rgt:3

-C Lft:4 Rgt:7

-D lft:5 Rgt:6

-E Lft:9 Rgt:12

-F Lft:10 rgt:11

Calculation of Treegrid Record Properties LfT and RGT in Jqgrid