15.1 枚举类型 枚举定义的符号是常量值. C#编译器编译时,会用数值替换符号,不再引用定义了符号的枚举类型.可能会出现一些版本问题. Enum.IsDefined(Type enumType, object value)方法被经常用于参数校验: public void SetColor(ConsoleColor c) { if (!Enum.IsDefined(typeof(ConsoleColor), c)) { throw new ArgumentOutOfRangeException(…
编程语言的基元类型 某些数据类型如此常用,以至于许多编译器允许代码以简化的语法来操纵它们. System.Int32 a = new System.Int32(); // a = 0 a = 1; 等价于: int a = 1; 这种语法不仅增强了代码的可读性,其生成的IL代码与使用System.Int32时生成的IL代码是完全一致的. 编译器直接支持的数据类型称为基元类型(primitive type).基元类型直接映射到Framework类库(FCL)中存在的类型.如C#中,i…
There are four different strategies for representing an inheritance hierarchy: Use one table per concrete class and default runtime polymorphic behavior. Use one table per concrete class but discard polymorphism and inheritance relationships comple…
一.结构 二.Hibernate支持的UserTypes接口 UserType —You can transform values by interacting with the plain JDBC PreparedStatement (when storing data) and ResultSet (when loading data).By implementing this interface, you can also control how Hibernate caches a…
一.结构 二.代码 1. package org.jpwh.model.advanced; import java.io.Serializable; import java.math.BigDecimal; import java.util.Currency; /* This value-typed class should be <code>java.io.Serializable</code>: When Hibernate stores entity instance dat…
一.简介 1. 2. 3. 4. to override this default mapping. The JPA specification has a convenient shortcut annotation for this purpose, @Lob @Entity public class Item { @Lob protected byte[] image; @Lob protected String description; // ... } This maps the by…
