Conditional Query to Get full graph

Users Dgraph
1

I have a graph database like below
Country → hasRegion → Region → hasCity → City

Conditional query :
India → hasRegion
For each Region we got(Region1,Region2)
Check if Region1 > hasOtherName > ?
Found
use node we got from hasOtherName for hasCity call
Not Found
use Region node for hasCity call.

How to write this query, Please help me with syntax.

2

I have some clarifications to ensure I understand what you are asking.

Is this the set up you have?

12%20AM
12%20AM691×806 53.3 KB

If it is correct that you are set up this way, do you want to check if region has no Jharkhand then use West to find city?

3

Yes, that’s correct.

4

So I don’t think you can solve your problem as you have it with the functions that are available. I think a better way to structure would be like this so no matter which name of the region you can get to hasCity. Does this make sense?

53%20PM
53%20PM711×842 55 KB

5

I have re format the case for better understanding :

GRAPH :

		India  > hasRegion > East > hasCity > Kolkatta
		India  > hasRegion > West > hasCity > Pune
		India  > hasRegion > West > hasCity > Mumbai 
		India  > hasRegion > West > hasCity > Nagpur
		India  > hasRegion > RegionWest > hasCity > Nagpur

		RegionWest > hasPivotNode > West

TestCaseGraph_for_pivot_case
TestCaseGraph_for_pivot_case883×565 32.9 KB

Cases :

		Case1 : Cities of region RegionWest : 
		   RegionWest > hasPivotNode > (Found) West > hasCity ?
		   Expected Result :- Pune, Mumbai, Nagpur
						   
		Case2 : Cities of region East : 				   
		   East > hasPivotNode > (Not Found) East > hasCity ?
		   Expected Result :- Kolkatta

I need single conditional query for both of the above cases.

Note : I don’t have any scope to re model the graph.

6

@shanea please see if you can help me anyway.

7

For your case I believe that Recurse Query is ideal. We have nothing to do logical (conditional in this case) verification in the query. Unless you make a var block scheme (“waterfall” blocks). Or maybe use the logic found in math operations some how.

The most recommended would be you to expand your structure using @Recurse, hence in your application you control the logic of conditions.

https://docs.dgraph.io/query-language#recurse-query

8

Hey, check out this query and see if it works as intended.

{
  var(fun: has(hasRegion) @filter(eq(country, "India"))){
  name
  Region @filter( has(hasOtherName)) {
    R1 as uid
    name
    hasOtherName { R2 as uid }
  }
   RegionB2 : Region @filter(Not has(hasOtherName)) {
    R1a as uid
    name

  }
    Case1(fun: uid(R1, R2)){
      name
    }
    Case2(fun: uid(R1a)){
      name
    }
}