Update migration

services/headless-lms/migrations/20231201093550_add_combined_certificates_table.up.sql

@@ -1,13 +1,62 @@
-CREATE TABLE combined_certificates (
+ALTER TABLE course_module_certificate_configurations
+  RENAME TO certificate_configurations;
+ALTER TABLE course_module_certificates
+  RENAME TO generated_certificates;
+-- A certificate can be for many courses and for many modules. Conversly, course may have many certificates
+-- We will handle this many-to-many relationship with a join table
+CREATE TABLE certificate_configuration_to_requirements (
   id UUID DEFAULT uuid_generate_v4() PRIMARY KEY,
   created_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT now(),
   updated_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT now(),
-  deleted_at TIMESTAMP WITH TIME ZONE
+  deleted_at TIMESTAMP WITH TIME ZONE,
+  certificate_configuration_id UUID NOT NULL REFERENCES certificate_configurations(id),
+  course_instance_id UUID REFERENCES course_instances(id),
+  course_module_id UUID REFERENCES course_modules(id)
 );
 CREATE TRIGGER set_timestamp BEFORE
-UPDATE ON combined_certificates FOR EACH ROW EXECUTE PROCEDURE trigger_set_timestamp();
-COMMENT ON TABLE combined_certificates IS 'A combined certificate can be created when a student has completed multiple course modules. The modules can be from different courses, in which case the combined certificate functions as a certificate from multiple courses. See combined_certificate_to_course_modules for which course modules are required to be eligible for a combined certificate. See certificate_configurations on how the certificate is supposed to be rendered.';
-COMMENT ON COLUMN combined_certificates.id IS 'A unique, stable identifier for the record.';
-COMMENT ON COLUMN combined_certificates.created_at IS 'Timestamp when the record was created.';
-COMMENT ON COLUMN combined_certificates.updated_at IS 'Timestamp when the record was last updated. The field is updated automatically by the set_timestamp trigger.';
-COMMENT ON COLUMN combined_certificates.deleted_at IS 'Timestamp when the record was deleted. If null, the record is not deleted.';
+UPDATE ON certificate_configuration_to_requirements FOR EACH ROW EXECUTE PROCEDURE trigger_set_timestamp();
+COMMENT ON TABLE certificate_configuration_to_requirements IS 'A join table that can be used to figure out what course modules and course instances are required to be completed to be eligible for a specific certificate. Each row defines one requirement. To find out all requirements one will need to query for all rows that match a certificate configuration id. Note that this is the correct table if you want a certificate to relate to a course or to courses because all courses have course modules and course instances.';
+COMMENT ON COLUMN certificate_configuration_to_requirements.id IS 'A unique, stable identifier for the record.';
+COMMENT ON COLUMN certificate_configuration_to_requirements.created_at IS 'Timestamp when the record was created.';
+COMMENT ON COLUMN certificate_configuration_to_requirements.updated_at IS 'Timestamp when the record was last updated. The field is updated automatically by the set_timestamp trigger.';
+COMMENT ON COLUMN certificate_configuration_to_requirements.deleted_at IS 'Timestamp when the record was deleted. If null, the record is not deleted.';
+COMMENT ON COLUMN certificate_configuration_to_requirements.certificate_configuration_id IS 'Identifies the certificate this requirement is for.';
+COMMENT ON COLUMN certificate_configuration_to_requirements.course_instance_id IS 'If defined, the referred course instance is a requirement for this certificate.';
+COMMENT ON COLUMN certificate_configuration_to_requirements.course_module_id IS 'If defined, the referred course module is a requirement for this certificate.';
+-- TODO: is this a good idea?
+ALTER TABLE certificate_configuration_to_requirements
+ADD CONSTRAINT one_requirement_per_row CHECK num_nonnulls(
+    course_instance_id,
+    course_module_id,
+  ) = 1;
+COMMENT ON CONSTRAINT one_requirement_per_row ON certificate_configuration_to_requirements IS 'Each row can define only one requirement. If you want multiple requirements for a certificate, add more rows.';
+-- Generated certificates cannot no longer refer directly refer to the requirements as there may be many of them
+-- We'll migrate the table to refer to the configuration instead
+ALTER TABLE generated_certificates
+ADD COLUMN certificate_configuration_id UUID REFERENCES certificate_configurations(id);
+UPDATE generated_certificates gs
+SET certificate_configuration_id = (
+    SELECT id
+    FROM certificate_configurations cc
+    WHERE cc.course_instance_id = gs.course_instance_id
+      AND cc.course_module_id = gs.course_module_id
+  );
+ALTER TABLE generated_certificates
+ALTER COLUMN certificate_configuration_id
+SET NOT NULL;
+ALTER TABLE generated_certificates DROP COLUMN course_instance_id;
+ALTER TABLE generated_certificates DROP COLUMN course_module_id;
+-- Move the requirements from the certificate configurations table to the new join table
+INSERT INTO certificate_configuration_to_requirements (
+    certificate_configuration_id,
+    course_instance_id,
+    course_module_id
+  )
+VALUES
+SELECT id,
+  course_instance_id,
+  course_module_id
+FROM certificate_configurations
+WHERE deleted_at IS NULL;
+ALTER TABLE certificate_configurations DROP COLUMN course_instance_id;
+ALTER TABLE certificate_configurations DROP COLUMN course_module_id;