Need to show SQL data in tree view with lazy loading.

[DURGAPRASAD NEELAM]

Hi,

I have a huge data in mysql data base. The data in data base as follows for example.

Level	   Date	        name	       rank
0	   1/1/15	 Rajesh	        1
1	   1/1/15	 Krish	        2
2	   1/1/15        Ram	        3
1	   1/1/15        Krish 	        4
0	   1/1/15        Krish	        5
1	   1/1/15	 Krish	        6
1	   1/1/15	 Krish	        7	   
0
1
1
2
2
1
.
.
.

Level	   Date	        name	       rank
0	   1/1/15	 Rajesh	        1
1	   1/1/15	 Krish	        2
2	   1/1/15        Ram	        3
1	   1/1/15        Krish 	        4
0	   1/1/15        Krish	        5
1	   1/1/15	 Krish	        6
1	   1/1/15	 Krish	        7	   
0
1
1
2
2
1
.
.
.

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So, From the above table I need to build the tree view based on level column.
All zeros are parents followed by 1’s are child's of 0's above that, and 2’s are child's of 1’s above that (tree should be formed as below).



Tree:

0
---------1
---------------------------2
----------1
0
-----------1
-----------1
0
-----------1
-----------1
---------------------------2
---------------------------2
------------1

I have huge set of records, more than 20 lak , here I have to do lazy loading i.e. I should not read all the data and put in some container and then building parent and child relationship.

Lazy Loading: instead of reading and putting all the data memory, read the data which is currently viewing.

Here I have to do lazy loading, I want read the data of how many tree items I am showing on view currently.
I am not able to get how to build parent and child relationship with this requirement,
Any suggestions for the above requirement ???

Requirement = Mysql data base (huge set of data) + Tree view + Lazy loading. (I am using Qt 4.8.5)


Thanks in advance.