ORA-01706：用户功能结果值太大

Question

当尝试提取xml字段时，出现上述错误

    public static class RoadmapService
    {
        static ConkerDbEntities dbContext;
        public static void createDbContext(ConkerDbEntities _dbContext)
        {
            dbContext = _dbContext;
        }

        public static void addToDatabase(Form form)
        {
            Roadmaps roadmap = new Roadmaps { RoadmapTitle = form.title, 
                                              RoadmapSummary = form.summary, 
                                              RoadmapBody = form.body };

            var tags = new Tags[form.tags.Length];

            for(int i = 0; i < tags.Length; i++)
            {
                tags[i] = new Tags();
                tags[i].TagId = form.tags[i];
            }

            var roadmapTags = new RoadmapTags[form.tags.Length];

            for(int i = 0; i < tags.Length; i++)
            {
                roadmapTags[i] = new RoadmapTags{Roadmap = roadmap, Tag = tags[i]};
            }

            dbContext.AddRange(roadmapTags);
            dbContext.SaveChangesAsync();
        }
    }
}