Function DeleteBeforeAssociations

callbacks/delete.go:26–111

(db *gorm.DB)

}

func DeleteBeforeAssociations(db *gorm.DB) {
	if db.Error == nil && db.Statement.Schema != nil {
		selectColumns, restricted := db.Statement.SelectAndOmitColumns(true, false)
		if !restricted {
			return
		}

		for column, v := range selectColumns {
			if !v {
				continue
			}

			rel, ok := db.Statement.Schema.Relationships.Relations[column]
			if !ok {
				continue
			}

			switch rel.Type {
			case schema.HasOne, schema.HasMany:
				queryConds := rel.ToQueryConditions(db.Statement.Context, db.Statement.ReflectValue)
				modelValue := reflect.New(rel.FieldSchema.ModelType).Interface()
				tx := db.Session(&gorm.Session{NewDB: true}).Model(modelValue)
				withoutConditions := false
				if db.Statement.Unscoped {
					tx = tx.Unscoped()
				}

				if len(db.Statement.Selects) > 0 {
					selects := make([]string, 0, len(db.Statement.Selects))
					for _, s := range db.Statement.Selects {
						if s == clause.Associations {
							selects = append(selects, s)
						} else if columnPrefix := column + "."; strings.HasPrefix(s, columnPrefix) {
							selects = append(selects, strings.TrimPrefix(s, columnPrefix))
						}
					}

					if len(selects) > 0 {
						tx = tx.Select(selects)
					}
				}

				for _, cond := range queryConds {
					if c, ok := cond.(clause.IN); ok && len(c.Values) == 0 {
						withoutConditions = true
						break
					}
				}

				if !withoutConditions && db.AddError(tx.Clauses(clause.Where{Exprs: queryConds}).Delete(modelValue).Error) != nil {
					return
				}
			case schema.Many2Many:
				var (
					queryConds     = make([]clause.Expression, 0, len(rel.References))
					foreignFields  = make([]*schema.Field, 0, len(rel.References))
					relForeignKeys = make([]string, 0, len(rel.References))
					modelValue     = reflect.New(rel.JoinTable.ModelType).Interface()