Handle the fact that FK names are not always unique.

[nvoxland]

Description

Update ForeignKeyComparator logic to work like PrimaryKeyComparitor which already assumes primary key names are only unique within the table name.

Fixes #2227

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Dev Handoff Notes (Internal Use)

Links

• Fixed Issue: Diff: Foreign keys in different tables but with matching names are seen as the same objects #2227
• Test Results: https://github.com/liquibase/liquibase/pull/2228/checks

Testing

• Steps to Reproduce: Diff: Foreign keys in different tables but with matching names are seen as the same objects #2227
• Guidance:
  • Impact: Logic used for uniquely identifying foreign keys in snapshot/diff/diffChangeLog logic

Dev Verification

With the change, I get

Missing Foreign Key(s): 
     fk_test_fk(table2[id] -> table1[id])

Test Requirements (Liquibase Internal QA)

You need two Postgres instances to test this fix. Postgres version does not matter; I reproed using a PG 12 and a PG 9.

Setup:

On one PG instance, execute the following SQL:

create table table1 (id int primary key);
create table table2 (id int primary key);
alter table table1 add constraint fk_test_fk FOREIGN KEY (id) references table1(id);
alter table table2 add constraint fk_test_fk FOREIGN KEY (id) references table1(id);

On the second PG instance, execute the following SQL:

create table table1 (id int primary key);
create table table2 (id int primary key);
alter table table1 add constraint fk_test_fk FOREIGN KEY (id) references table1(id);

The difference is the missing foreign key on table2 on the second instance.

Manual Tests

Verify liquibase diff shows a unexpected foreign key fk_test_fk from table2(id) to table1(id).

• In liquibase.properties, specify url as the first database and referenceUrl as the second database.
• liquibase diff --schemas public

Verify liquibase diffChangeLog has an ALTER TABLE to drop a foreign key fk_test_fk from table2(id) to table1(id).

• In liquibase.properties, specify url as the first database and referenceUrl as the second database.
• liquibase diff-changelog --changelog-file gcl_dropFk.postgres.sql --schemas public
  • The SQL output to the changelog is:
  • ALTER TABLE table2 DROP FOREIGN KEY fk_test_fk;

Verify reversing the order of the diff shows an missing foreign key fk_test_fk from table2(id) to table1(id).

• In liquibase.properties, specify url as the second database and referenceUrl as the first database.
• liquibase diff --schemas public

Verify reversing the order of databases during diff-changelog generates a ALTER TABLE to add a foreign key fk_test_fk from table2(id) to table1(id).

• In liquibase.properties, specify url as the second database and referenceUrl as the first database.
• liquibase diff-changelog --changelog-file gcl_addFk.postgres.sql --schemas public
  • The SQL output to the changelog is:
  • alter table table2 add constraint fk_test_fk FOREIGN KEY (id) references table1(id);

Verify liquibase update using changelog gcl_dropFK.postgres.sql correctly drops the foreign key from the first database.

(Note: I added this test case because I have a suspicion that if the SQL to drop the FK will throw an error on update because there are two “fk_test_fk” foreign keys on table1. If there is no error during update itself, verify that the correct/expected foreign key is dropped.)

• In liquibase.properties, specify url as the first database. (In this test referenceUrl is not used).
• liquibase update --changelog-file gcl_dropFk.postgres.sql
  • Update is successful.
  • Validation directly on the database confirms the foreign key on table1 from table2 is dropped.

Automated Tests

• None. There are sufficient integration/dev tests for testing foreign keys.

┆Issue is synchronized with this Jira Bug by Unito