orm

Cannot retrieve the latest update value from database after running the ORM Lite UpdateBuilder.update() in android

由 ♀尐吖头ヾ 提交于 2020-01-16 20:07:02
问题 I have trouble when updating the data in android by using ORM Lite because my updated data is not affected in database immediately. After the update process, I query the data from the database but I got the old data that was the same as before I update. So, I solved this problem by refreshing each updated object by using refresh(Object) after the update process, the problem was OK(I can access the latest updated data from data in next query). But I am not sure is it the best way or not? If

Cannot retrieve the latest update value from database after running the ORM Lite UpdateBuilder.update() in android

由 纵然是瞬间 提交于 2020-01-16 20:06:18
问题 I have trouble when updating the data in android by using ORM Lite because my updated data is not affected in database immediately. After the update process, I query the data from the database but I got the old data that was the same as before I update. So, I solved this problem by refreshing each updated object by using refresh(Object) after the update process, the problem was OK(I can access the latest updated data from data in next query). But I am not sure is it the best way or not? If

django06: ORM示例2--uer 与file

由 半城伤御伤魂 提交于 2020-01-16 18:49:26
存放路径： https://git.lug.ustc.edu.cn/ 笔记 外键与多键 path = models.ForeignKey(to="Path") file = models.ManyToManyField(to="File") code 处理方式 new_path = request.POST.get("new_path",None) models.File.objects.create(name=new_user,path_id=new_path) // 多键 files = request.POST.getlist("files") user_obj = models.User.objects.create(name=new_user) user_obj.file.set(files) 来源： CSDN 作者： 砌砖 链接： https://blog.csdn.net/winterye12/article/details/104007603

What is the difference between persist() and merge() in JPA and Hibernate?

由 自作多情 提交于 2020-01-16 12:09:14
问题 What is the difference between persist() and merge() in Hibernate? persist() can create a UPDATE & INSERT query, eg: SessionFactory sef = cfg.buildSessionFactory(); Session session = sef.openSession(); A a=new A(); session.persist(a); a.setName("Mario"); session.flush(); in this case query will be generated like this: Hibernate: insert into A (NAME, ID) values (?, ?) Hibernate: update A set NAME=? where ID=? so persist() method can generate an Insert and an Update. Now with merge() :

how to deal with doctrine's lazy loading when having null-objects?

由 随声附和 提交于 2020-01-16 05:12:14
问题 i have a question about the correct way to handle doctrine's lazy loading mechanism. I have an entity that references another one via @ManyToOne: class Entity { ... /** * @ManyToOne(targetEntity="AnotherEntity") * @JoinColumn(name="anotherEntityId", referencedColumnName="id") */ protected $anotherEntity; ... } class AnotherEntity { /** * @var integer $id * @Column(name="id", type="integer", nullable=false) * @Id * @GeneratedValue(strategy="IDENTITY") */ private $id; /** * @var string

Define Laravel Eloquent relations between 3 models in a messaging system

由 我只是一个虾纸丫 提交于 2020-01-16 00:47:31
问题 I'm trying to create multi-participant messaging system. Here's the database design I'v found here: Messaging system database schema Conversation ------------ id Messages -------- id conversation_id from_id subject message from_timestamp Participants ------------ conversation_id user_id last_read_timestamp Could you help me to describe Eloquent relations between these models? I mean this: http://laravel.com/docs/eloquent#relationships 回答1: class Conversation extends Eloquent { public function

C# Database Mapper

由 ∥☆過路亽．° 提交于 2020-01-15 18:44:50
问题 I was looking to map my database query results to strongly type objects in my c# code. So i wrote a quick and dirty helper method on the SqlConnection class which runs the query on the database and uses reflection to map the record columns to the object properties. The code is below: public static T Query<T>(this SqlConnection conn, string query) where T : new() { T obj = default(T); using (SqlCommand command = new SqlCommand(query, conn)) { using (SqlDataReader reader = command.ExecuteReader

python中mysql单表curd基于orm

由 谁说胖子不能爱 提交于 2020-01-15 13:02:24
应用demo下，models新建一个People类继承models.Model # People类 class People(models.Model): name = models.CharField(max_length=20) age = models.IntegerField(max_length=3) addr = models.CharField(max_length=32) sex = models.IntegerField(default=0, max_length=1) 生成迁移文件 ： 进入项目根目录 > cmd > python manage.py makemigrations 写入到数据库 ： python manage.py migrate 对数据库的单表curd # 添加 def add_people(request): # 方式一添加 创建People对象 调用save()方法 p = People(name="小明", age=12, sex=1, addr="中国") p.save() # 方式二添加 使用People.objects.create() People.objects.create(name="熊二", age=10, sex=2, addr="森林") # 添加传入的参数可以是字典，键名字跟数据库字段一样 dic = { "name

How can I select count(field) and still get an object with createQueryBuilder

由 独自空忆成欢 提交于 2020-01-15 12:05:25
问题 I want to access a query result in twig as a whole object. In the query however, I want to select just several fields from the tables + count . In my example I have a company, which is owned by an owner and has several employees. I want to create a query, which gives me a list of companies ordered by count of their employees. $qb = $this->createQueryBuilder('c'); $qb->select('count(e.id), partial c.{id, name}, partial o.{id, name}'); $qb->leftJoin('c.employees', 'e'); $qb->innerJoin('c.owner'

Trying to understand how to abstract my data access layer

由 元气小坏坏 提交于 2020-01-15 10:49:16
问题 I'm writing an application that is used to catalog files, and attribute those files with meta data. A photo album program would be a good comparison to what I'm trying to do. I'm trying to abstract the interface between my program and the file system which stores the files, and the database which stores the meta data for the files. This is to allow for mocking and unit testing. In addition, I'd like to be able to create multiple implementations of my tool that can leverage different database
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