Invalid SQL generated when non-root entity in aggregate has a collection
jamoamo opened this issue · comments
If I have a nested entity aggregate where somewhere in the nest (not the root) there is a one-to-one relationship with a nested one-to-many relationship, the query from the one-to-many relationship entity will reference the incorrect column name. That sounds vague, even to me, so let me illustrate.
If I have a database structure such as below (imagine foreign keys from c -> b and b -> c):
CREATE TABLE a (a_id INT)
CREATE TABLE b (b_id INT, a INT)
CREATE TABLE c (c_id INT, b INT)
and entities for each table as follows (extraneous code excluded) where A contains a one-to-one relationship with B and B contains a one-to-many relationship with C.
public class C {
@Id
private int cId;
}
public class B {
@Id
private int bId;
private Set<C> cChild;
}
public class A {
@Id
private int aId;
private B bChild;
}
The above will result in an exception when querying the root of the aggregate using a repository bean along the lines of
org.springframework.jdbc.BadSqlGrammarException: PreparedStatementCallback; bad SQL grammar [SELECT "C"."C_ID" AS "C_ID" FROM "C" WHERE "C"."A_ID" = ?]
The generated SQL makes use of a column which does not exist in the table 'c' but only exists in table 'a'.
A workaround is to make the relationship between A and B to be a one-to-many relationship.
There is a minimalist project that reproduces the bug at https://github.com/jamoamo/spring-data-bug-reproducer
