update

Entity-Relationship.md

@@ -12,7 +12,7 @@ What can navigation attributes do?
 - [《Cascade Deletion》](Cascade-Deletion)
 - [《AggregateRoot Repository》](%E8%81%9A%E5%90%88%E6%A0%B9%EF%BC%88%E5%AE%9E%E9%AA%8C%E5%AE%A4%EF%BC%89)
 
-# Custom Navigation Relationship
+## Custom Navigation Relationship
 
 OneToMany/ManyToMany supported types: ICollection\<T\>、List\<T\>、ObservableCollection\<T\>
 
@@ -58,7 +58,7 @@ fsql.CodeFirst.ConfigEntity<YOUR_ENTITY>(a => a
 
 > Warm-up description: The navigation attribute configuration is loaded because it is necessary to solve the dead cycle reference. When the mutual reference relationship is very complex, it may cause the first use of navigation attributes to fail. The second time is enough. The solution is to warm up all entity classes when the program starts, and execute fsql.Select\<object\>().AsType(entityClass) in a loop;
 
-# Associate with non-primary key
+## Associate with non-primary key
 
 ```csharp
 //OneToMany
@@ -88,7 +88,30 @@ Method signature:
 GetTableRef(string propertyName, bool isThrow);
 ```
 
-# PgArrayToMany
+## OneToOne
+
+```csharp
+class User
+{
+    [Key]
+    public int Id { get; set; }
+    [Navigate(nameof(Id))]
+    public UserExt Ext { get; set; }
+    //...
+}
+class UserExt
+{
+    [Key]
+    public int UserId { get; set; }
+    [Navigate(nameof(UserId))]
+    public User User { get; set; }
+    //...
+}
+```
+
+OneToOne, Require both sides to use the Navigate feature to associate with their own 'primary key'. (Supports cascading save and deletion)
+
+## PgArrayToMany
 
 ```csharp
 class User

实体关系.md

@@ -14,7 +14,7 @@ FreeSql 提供 OneToMany, ManyToOne, ManyToMany, OneToOne, Parent, [PgArrayToMan
 
 导航属性进行多表查询非常方便，lambda 表达式中直接使用导航对象点点点，舒服！！
 
-# 自定义配置
+## 自定义配置
 
 OneToMany/ManyToMany 支持的类型：ICollection\<T\>、List\<T\>、ObservableCollection\<T\>
 
@@ -60,7 +60,7 @@ fsql.CodeFirst.ConfigEntity<T>(a => a
 
 > 预热说明：导航属性配置的加载，因为要解决死循环引用，当相互引用关系很复杂的时候，可能导致首次使用导航属性失败，第二次就可以了。解决办法可以程序启动时就预热所有实体类，循环执行 fsql.Select\<object\>().AsType(实体类);
 
-# 与非主键关联
+## 与非主键关联
 
 ```csharp
 //OneToMany
@@ -74,7 +74,7 @@ public Group Group { get; set; }
 
 非主键关联权支持 OneToMany/ManyToOne 两种关系，并且只能在查询的时候有效。（不支持级联保存、级联删除）
 
-# 检测导航属性
+## 检测导航属性
 
 如何检测一个导航属性是否有效：
 
@@ -86,7 +86,31 @@ var tbref = fsql.CodeFirst
 
 GetTableRef(string propertyName, bool isThrow);
 
-# PgArrayToMany
+## OneToOne
+
+```csharp
+class User
+{
+    [Key]
+    public int Id { get; set; }
+    [Navigate(nameof(Id))]
+    public UserExt Ext { get; set; }
+    //...
+}
+class UserExt
+{
+    [Key]
+    public int UserId { get; set; }
+    [Navigate(nameof(UserId))]
+    public User User { get; set; }
+    //...
+}
+```
+
+一对一，要求两边都使用 Navigate 特性与自身的【主键】关联。（支持级联保存，级联删除）
+
+
+## PgArrayToMany
 
 ```csharp
 class User
@@ -105,7 +129,7 @@ class Role
 
 更多资料：[#1145](https://github.com/dotnetcore/FreeSql/issues/1145)
 
-# 约定命名（无须指明 Navigate）
+## 约定命名（无须指明 Navigate）
 
 提示：本节内容稍微了解即可，不是必须掌握的，可以跳过。