但是在关系数据库中,关联是双向的。这意味着 m:n 的关系必须用第三张表来存储两表之间的关系。甚至在一个简单的 1:n 关系中,1 这一方,是不知道 n 那边到底有多少个的,除非在某个之后做一次 JOIN。 表结构所有权的冲突 到底是对象的结构决定了表结构,还是表结构决定了对象的结构?是业务开发者说了算,还是...
1. Q: How to guarantee the quality of your products ? A: All goods are new and original with 365 days guarantee. . 2. Q: Could Heneng Trade provide Technology Support? A: We're in this field many year. If there's any problem, please contact us,we'll pro...
这个查询封装是我在CodePlex中无意中看到的,具体的项目地址:点我进入,这个项目是《NHibernate with ASP.net Problem-Design-Solution》一书中贯穿讲解NHibernate的,其中对于查询的封装做的很好,而且使用起来也很方便,原版代码是VB.NET的,我这边附上C#版本的,主要步骤如下: 1、建立实体类CriteriaParameter用来包装作为参...
跟踪训练根据句意和首字母提示完成单词。1. Problems and worries ar e n ormal in life.2. When you learn English, don't b e afraid of making m istakes.3. With th e help of my teacher, I s olved th e problem.4. H e is a good teacher though h e doesn't hav e much e xper...
这个查询封装是我在CodePlex中无意中看到的,具体的项目地址:点我进入,这个项目是《NHibernate with ASP.net Problem-Design-Solution》一书中贯穿讲解NHibernate的,其中对于查询的封装做的很好,而且使用起来也很方便,原版代码是VB.NET的,我这边附上C#版本的,主要步骤如下: ...
目的:减少sql查询次数,避免N+1问题,减少内存开销,适用于复杂关系 基本使用: 结构体定义:gorm:"foreignKey:problem_id;references:id"指明关联关系,gorm会根据该关系进行预加载。如下面例子中把Struct111的problem_id与ProblemBasic的id关联起来。 // 要使用预加载函数的结构体type ProblemBasic struct { ID uint `go...
二、根据首字母或中文提示,完成下列句子1. We can get back to the n ormal life now.2. It is important to keep calm in an emergency(紧急情况).3. You'll lose your slim figure if you don't watch out.4. An added problem is the growing concern (担心) for the environment.5. The b ...
It was interesting to dive into the problem of object-relational mapping, it helped me realize how difficult this task was. Later on, when I encountered NHibernate, it was even more interesting to compare my design decisions to those of NHibernate. Although it wasn’t terribly pleasant to se...
Every application written outside of SQL uses an ORM. Whether it’s hand-rolled ADO.NET code, or NHibernate, you have to bridge the gap from .NET to SQL. Bridging this gap is a hard problem to solve, and nothing solves the entire problem set perfectly. Nor should it!
1. Q: How to guarantee the quality of your products ? A: All goods are new and original with 365 days guarantee. . 2. Q: Could Heneng Trade provide Technology Support? A: We're in this field many year. If there's any problem, please contact us,we'...