Function cascadeRecordDelete

core/record_model.go:1506–1574

cascadeRecordDelete triggers cascade deletion for the provided references. NB! This method is expected to be called from inside of a transaction.

(app App, mainRecord *Record, refs map[*Collection][]Field)

//
// NB! This method is expected to be called from inside of a transaction.
func cascadeRecordDelete(app App, mainRecord *Record, refs map[*Collection][]Field) error {
	// Sort the refs keys to ensure that the cascade events firing order is always the same.
	// This is not necessary for the operation to function correctly but it helps having deterministic output during testing.
	sortedRefKeys := make([]*Collection, 0, len(refs))
	for k := range refs {
		sortedRefKeys = append(sortedRefKeys, k)
	}
	sort.Slice(sortedRefKeys, func(i, j int) bool {
		return sortedRefKeys[i].Name < sortedRefKeys[j].Name
	})

	for _, refCollection := range sortedRefKeys {
		fields, ok := refs[refCollection]

		if !ok || refCollection.IsView() {
			continue // skip missing or view collections
		}

		recordTableName := inflector.Columnify(refCollection.Name)

		for _, field := range fields {
			prefixedFieldName := recordTableName + "." + inflector.Columnify(field.GetName())

			query := app.RecordQuery(refCollection)

			if opt, ok := field.(MultiValuer); !ok || !opt.IsMultiple() {
				query.AndWhere(dbx.HashExp{prefixedFieldName: mainRecord.Id})
			} else {
				query.AndWhere(dbx.Exists(dbx.NewExp(fmt.Sprintf(
					`SELECT 1 FROM %s {{__je__}} WHERE [[__je__.value]]={:jevalue}`,
					dbutils.JSONEach(prefixedFieldName),
				), dbx.Params{
					"jevalue": mainRecord.Id,
				})))
			}

			if refCollection.Id == mainRecord.Collection().Id {
				query.AndWhere(dbx.Not(dbx.HashExp{recordTableName + ".id": mainRecord.Id}))
			}

			// trigger cascade for each batchSize rel items until there is none
			batchSize := 4000
			rows := make([]*Record, 0, batchSize)
			for {
				if err := query.Limit(int64(batchSize)).All(&rows); err != nil {
					return err
				}

				total := len(rows)
				if total == 0 {
					break
				}

				err := deleteRefRecords(app, mainRecord, rows, field)
				if err != nil {
					return err
				}