Query: AQL: variable '$OLD' is assigned multiple times

Question

I want to update the following data in a nested loop. While doing this, I need to get data from the upper loops. I sent the data by cutting it a bit. There are more nested arrays. When I try to fetch data from the parent loop I get the following error. I've tried many variations, for example when I just try to RETURN it works fine but it won't let me use it in UPSERT. so like this

DATA:

[
  {
    "I": 28,
    "C": [
      {
        "I": 50,
        "L": [
          {
            "I": 1783,
            "E": [
              {
                "I": 5107194
              },
              {
                "I": 5184134
              },
              {
                "I": 5030548
              },
              {
                "I": 5069351
              }
            ]
          }
        ]
      }
    ]
  }
]

WORKS FINE:

FOR sport IN ${data}
    FOR country IN sport.C
        FOR league IN country.L
            UPSERT { I: league.I } 
            INSERT { I: league.I, C: country.I, S: sport.I } 
            UPDATE { I: league.I, C: country.I, S: sport.I } IN leagues
            
            FOR event IN league.E
                RETURN {
                    I: event.I,
                    L: league.I
                }

Query: AQL: variable '$OLD' is assigned multiple times (while parsing):

FOR sport IN ${data}
    FOR country IN sport.C
        FOR league IN country.L
            UPSERT { I: league.I } 
            INSERT { I: league.I, C: country.I, S: sport.I } 
            UPDATE { I: league.I, C: country.I, S: sport.I } IN leagues
            
            FOR event IN league.E
                UPSERT { I: event.I }
                INSERT {
                    I: event.I,
                    L: league.I
                }
                UPDATE { 
                    I: event.I,
                    L: league.I
                } IN events

As I said, there are more arrays nested inside each other. How can I solve this?

Answer 1

You can put the first UPSERT in a subquery like this:

FOR sport IN ${data}
    FOR country IN sport.C
        FOR league IN country.L
            LET dummy = (
              UPSERT { I: league.I } 
              INSERT { I: league.I, C: country.I, S: sport.I } 
              UPDATE { I: league.I, C: country.I, S: sport.I } IN leagues
            )
            
            FOR event IN league.E
                UPSERT { I: event.I }
                INSERT {
                    I: event.I,
                    L: league.I
                }
                UPDATE { 
                    I: event.I,
                    L: league.I
                } IN events

This way the scope of the implicit $OLD variable introduced by the first UPSERT is limited to that subquery and therefore does not conflict with the second UPSERT.