I have a table in which the foreign key refers to the id of the same table. I need to find the children of the first element that pass me as a parameter, until I reach a certain level.
I need to find all the children of one element.
The first time I had the ID_FK, but after, I
" ";"ID";"ID_FK";"ISLAST" "1";"12519";"12518";"N" "2";"12520";"12518";"N" "3";"12521";"12518";"N" "4";"12522";"12518";"N" "5";"12523";"12518";"N"
But afterwards, I have to find each of the results of the ID column, in the ID_FK field, until I find an S in the ISLAST column.
"ID";"ID_FK";"ISLAST" "12543";"12519";"N"
Recursive until:
"ID";"ID_FK";"ISLAST" "12519";"12568";"S"
The result:
" ";"ID";"ID_FK";"ISLAST" "1";"12519";"555018";"s" "2";"12520";"112318";"s" "3";"12521";"128818";"s" "4";"12522";"133888";"s" "5";"12523";"125888";"s"
I need a query to do this, to be able to pass it to JPA, or else, a way or some idea of how to do it with JPA directly with Entities and recursion.
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Answer
JPA does not support recursion.
You will have to use SQL.
Here is the documentation of PostgreSQL and its recursive functionality:
https://www.postgresql.org/docs/current/queries-with.html
And here the documentation of Oracle for recursive queries:
https://docs.oracle.com/cd/B19306_01/server.102/b14200/queries003.htm