EFCodeFirst关系映射约定

EFCodeFirst关系映射约定

EFCodeFirst

关系映射约定

默认多重关系的一些约定规则：
1.一对多关系
两个类中分别包含一个引用和一个集合属性。
两个类中一个类包含另一个类的引用属性。
两个类中一个类包含另一个类的集合属性。
2.多对多关系
两个类分别包含对方的一个集合属性。
3.一对一关系
两个类分别包含对方的一个引用属性。

1.外键列名默认约定

3种外键列名的约定方式是：

• [Target Type Key Name]，[目标类型的键名]
• [Target Type Name] + [Target Type Key Name]，[目标类型名称]+[目标类型键名称]
• [Navigation Property Name] + [Target Type Key Name]，[引用属性名称]+[目标类型键名称]

3种不同的外键名称命名之间存在优先级：

[目标类型的键名] > [引用属性名称]+[目标类型键名称] > [目标类型名称]+[目标类型键名称]。

1.[目标类型的键名]

• 两个类中分别包含一个引用和一个集合属性的一对多种。
• 启用级联删除功能。

2.[目标类型名称]+[目标类型键名称]

• 两个类中一个类包含另一个类的集合属性。

3.[引用属性名称]+[目标类型键名称]

2.一对多关系

修改外键命名约定，自定义外键列名

Data Annotations方式

1. public int CatID { get; set; } 

   ---

2. [ForeignKey("CatID")] 

   ---

3. public virtual Category Category { get; set; } 

   ---

4. //或者 

   ---

5. [ForeignKey("Category")] 

   ---

6. public int CatID { get; set; } 

   ---

7. public virtual Category Category { get; set; } 

   ---

Fluent API方式

• 两个实体类之间的关系，可以两个类中均添加关系映射配置，也可以只对其中任意一个实体类添加关系映射配置。
• 建议将实体类之间关系映射配置在包含外键的类中

1. modelBuilder.Entity<Product>() 

   ---

2. .HasRequired(t => t.Category) 

   ---

3. .WithMany(t => t.Products) 

   ---

4. .HasForeignKey(d => d.CatID); 

   ---

• 一对多关系关系生成的外键引用约束默认是有级联删除的，可以通过以下方式禁用Category与Product之间的级联删除。

1. protected override void OnModelCreating(DbModelBuilder modelBuilder) 

   ---

2. { 

   ---

3. modelBuilder.Entity<Product>() 

   ---

4. .HasRequired(t => t.Category) 

   ---

5. .WithMany(t => t.Products) 

   ---

6. .HasForeignKey(d => d.CatID) 

   ---

7. .WillCascadeOnDelete(false); 

   ---

8. } 

   ---

9. //也可以在Entity Framework Code First生成的全部表中都统一设置禁用一对多级联删除。 

   ---

10. protected override void OnModelCreating(DbModelBuilder modelBuilder) 

    ---

11. { 

    ---

12. modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>(); 

    ---

13. } 

    ---

• 可以支持外键列名自定义的，但在实际的项目中，更多的外键列名称还是与所引用表的主键列名相同。

3.一对一关系

• 两个表均有各自的主键，但要看哪个表的主键同时作为外键引用另一个表的主键。

Data Annotations方式

UserProfile表中的主键ProfileID同时也作为外键引用User表中的主键UserID。
User为主表

1. public partial class User 

   ---

2. { 

   ---

3. [Key] 

   ---

4. public int UserID { get; set; } 

   ---

5. public string UserName { get; set; } 

   ---

6. public string Password { get; set; } 

   ---

7. public Nullable<bool> IsValid { get; set; } 

   ---

8.  

   ---

9. public virtual UserProfile UserProfile { get; set; } 

   ---

10. } 

    ---

11.  

    ---

12. ------------------------------------------------------------------------------------------ 

    ---

13. public partial class UserProfile 

    ---

14. { 

    ---

15. [Key] 

    ---

16. [ForeignKey("User")] 

    ---

17. public int ProfileID { get; set; } 

    ---

18. public string Name { get; set; } 

    ---

19. public Nullable<bool> Sex { get; set; } 

    ---

20. public Nullable<DateTime> Birthday { get; set; } 

    ---

21. public string Email { get; set; } 

    ---

22. public string Telephone { get; set; } 

    ---

23. public string Mobilephone { get; set; } 

    ---

24. public string Address { get; set; } 

    ---

25. public Nullable<DateTime> CreateDate { get; set; } 

    ---

26.  

    ---

27. public virtual User User { get; set; } 

    ---

28. } 

    ---

表User主键UserID将同时作为外键引用UserProfile表的主键ProfileID。
UserProfile为主表

1. public partial class User 

   ---

2. { 

   ---

3. [Key] 

   ---

4. [ForeignKey("UserProfile")] 

   ---

5. public int UserID { get; set; } 

   ---

6. public string UserName { get; set; } 

   ---

7. public string Password { get; set; } 

   ---

8. public Nullable<bool> IsValid { get; set; } 

   ---

9.  

   ---

10. public virtual UserProfile UserProfile { get; set; } 

    ---

11. } 

    ---

12.  

    ---

13. ------------------------------------------------------------------------------------------ 

    ---

14. public partial class UserProfile 

    ---

15. { 

    ---

16. [Key] 

    ---

17. public int ProfileID { get; set; } 

    ---

18. public string Name { get; set; } 

    ---

19. public Nullable<bool> Sex { get; set; } 

    ---

20. public Nullable<DateTime> Birthday { get; set; } 

    ---

21. public string Email { get; set; } 

    ---

22. public string Telephone { get; set; } 

    ---

23. public string Mobilephone { get; set; } 

    ---

24. public string Address { get; set; } 

    ---

25. public Nullable<DateTime> CreateDate { get; set; } 

    ---

26.  

    ---

27. public virtual User User { get; set; } 

    ---

28. } 

    ---

Fluent API方式

UserProfile表中的主键ProfileID同时也作为外键引用User表中的主键UserID。
User为主表

1. public partial class User 

   ---

2. { 

   ---

3. public int UserID { get; set; } 

   ---

4. public string UserName { get; set; } 

   ---

5. public string Password { get; set; } 

   ---

6. public Nullable<bool> IsValid { get; set; } 

   ---

7.  

   ---

8. public virtual UserProfile UserProfile { get; set; } 

   ---

9. } 

   ---

10. ------------------------------------------------------------------------------------------ 

    ---

11. public class UserMap : EntityTypeConfiguration<User> 

    ---

12. { 

    ---

13. public UserMap() 

    ---

14. { 

    ---

15. // Primary Key 

    ---

16. this.HasKey(t => t.UserID); 

    ---

17.  

    ---

18. // Properties 

    ---

19. this.Property(t => t.UserName) 

    ---

20. .HasMaxLength(50); 

    ---

21.  

    ---

22. this.Property(t => t.Password) 

    ---

23. .HasMaxLength(100); 

    ---

24.  

    ---

25. // Table & Column Mappings 

    ---

26. this.ToTable("User"); 

    ---

27. this.Property(t => t.UserID).HasColumnName("UserID"); 

    ---

28. this.Property(t => t.UserName).HasColumnName("UserName"); 

    ---

29. this.Property(t => t.Password).HasColumnName("Password"); 

    ---

30. this.Property(t => t.IsValid).HasColumnName("IsValid"); 

    ---

31. } 

    ---

32. } 

    ---

33. ------------------------------------------------------------------------------------------  

    ---

34. public partial class UserProfile 

    ---

35. { 

    ---

36. public int UserID { get; set; } 

    ---

37. public string Name { get; set; } 

    ---

38. public Nullable<bool> Sex { get; set; } 

    ---

39. public Nullable<DateTime> Birthday { get; set; } 

    ---

40. public string Email { get; set; } 

    ---

41. public string Telephone { get; set; } 

    ---

42. public string Mobilephone { get; set; } 

    ---

43. public string Address { get; set; } 

    ---

44. public Nullable<DateTime> CreateDate { get; set; } 

    ---

45.  

    ---

46. public virtual User User { get; set; } 

    ---

47. } 

    ---

48. ------------------------------------------------------------------------------------------  

    ---

49. public class UserProfileMap : EntityTypeConfiguration<UserProfile> 

    ---

50. { 

    ---

51. public UserProfileMap() 

    ---

52. { 

    ---

53. // Primary Key 

    ---

54. this.HasKey(t => t.UserID); 

    ---

55.  

    ---

56. // Properties 

    ---

57. this.Property(t => t.UserID) 

    ---

58. .HasDatabaseGeneratedOption(DatabaseGeneratedOption.None); 

    ---

59.  

    ---

60. this.Property(t => t.Name) 

    ---

61. .IsRequired() 

    ---

62. .HasMaxLength(50); 

    ---

63.  

    ---

64. this.Property(t => t.Email) 

    ---

65. .IsRequired() 

    ---

66. .HasMaxLength(100); 

    ---

67.  

    ---

68. this.Property(t => t.Telephone) 

    ---

69. .HasMaxLength(50); 

    ---

70.  

    ---

71. this.Property(t => t.Mobilephone) 

    ---

72. .HasMaxLength(20); 

    ---

73.  

    ---

74. this.Property(t => t.Address) 

    ---

75. .HasMaxLength(200); 

    ---

76.  

    ---

77. // Table & Column Mappings 

    ---

78. this.ToTable("UserProfile"); 

    ---

79. this.Property(t => t.UserID).HasColumnName("UserID"); 

    ---

80. this.Property(t => t.Name).HasColumnName("Name"); 

    ---

81. this.Property(t => t.Sex).HasColumnName("Sex"); 

    ---

82. this.Property(t => t.Birthday).HasColumnName("Birthday"); 

    ---

83. this.Property(t => t.Email).HasColumnName("Email"); 

    ---

84. this.Property(t => t.Telephone).HasColumnName("Telephone"); 

    ---

85. this.Property(t => t.Mobilephone).HasColumnName("Mobilephone"); 

    ---

86. this.Property(t => t.Address).HasColumnName("Address"); 

    ---

87. this.Property(t => t.CreateDate).HasColumnName("CreateDate"); 

    ---

88.  

    ---

89. // Relationships 

    ---

90. this.HasRequired(t => t.User) 

    ---

91. .WithRequiredDependent(t => t.UserProfile); 

    ---

92. } 

    ---

93. } 

    ---

表User主键UserID将同时作为外键引用UserProfile表的主键ProfileID。
UserProfile为主表

1. public class UserProfileMap : EntityTypeConfiguration<UserProfile> 

   ---

2. { 

   ---

3. public UserProfileMap() 

   ---

4. { 

   ---

5. // Primary Key 

   ---

6. this.HasKey(t => t.UserID); 

   ---

7.  

   ---

8. // Properties 

   ---

9. this.Property(t => t.UserID) 

   ---

10. .HasDatabaseGeneratedOption(DatabaseGeneratedOption.None); 

    ---

11.  

    ---

12. this.Property(t => t.Name) 

    ---

13. .IsRequired() 

    ---

14. .HasMaxLength(50); 

    ---

15.  

    ---

16. this.Property(t => t.Email) 

    ---

17. .IsRequired() 

    ---

18. .HasMaxLength(100); 

    ---

19.  

    ---

20. this.Property(t => t.Telephone) 

    ---

21. .HasMaxLength(50); 

    ---

22.  

    ---

23. this.Property(t => t.Mobilephone) 

    ---

24. .HasMaxLength(20); 

    ---

25.  

    ---

26. this.Property(t => t.Address) 

    ---

27. .HasMaxLength(200); 

    ---

28.  

    ---

29. // Table & Column Mappings 

    ---

30. this.ToTable("UserProfile"); 

    ---

31. this.Property(t => t.UserID).HasColumnName("UserID"); 

    ---

32. this.Property(t => t.Name).HasColumnName("Name"); 

    ---

33. this.Property(t => t.Sex).HasColumnName("Sex"); 

    ---

34. this.Property(t => t.Birthday).HasColumnName("Birthday"); 

    ---

35. this.Property(t => t.Email).HasColumnName("Email"); 

    ---

36. this.Property(t => t.Telephone).HasColumnName("Telephone"); 

    ---

37. this.Property(t => t.Mobilephone).HasColumnName("Mobilephone"); 

    ---

38. this.Property(t => t.Address).HasColumnName("Address"); 

    ---

39. this.Property(t => t.CreateDate).HasColumnName("CreateDate"); 

    ---

40.  

    ---

41. // Relationships 

    ---

42. this.HasRequired(t => t.User) 

    ---

43. .WithRequiredPrincipal(t => t.UserProfile); 

    ---

44. } 

    ---

45. } 

    ---

4.多对多关系

• 除了生成实体类定义的属性表之外，还会生成一个中间表。用于体现两个实体表之间的多对多的关系。

1. public partial class User 

   ---

2. { 

   ---

3. public int UserID { get; set; } 

   ---

4. public string UserName { get; set; } 

   ---

5. public string Password { get; set; } 

   ---

6. public Nullable<bool> IsValid { get; set; } 

   ---

7.  

   ---

8. public virtual ICollection<Role> Roles { get; set; } 

   ---

9. } 

   ---

10.  

    ---

11. public partial class Role 

    ---

12. { 

    ---

13. public Role() 

    ---

14. { 

    ---

15. this.Users = new List<User>(); 

    ---

16. } 

    ---

17.  

    ---

18. public int RoleID { get; set; } 

    ---

19. public string RoleName { get; set; } 

    ---

20.  

    ---

21. public virtual ICollection<User> Users { get; set; } 

    ---

22. } 

    ---

• 默认启用多对多的数据级联删除

1.  

   ---

2. protected override void OnModelCreating(DbModelBuilder modelBuilder) 

   ---

3. { 

   ---

4. // 禁用多对多关系表的级联删除 

   ---

5. modelBuilder.Conventions.Remove<ManyToManyCascadeDeleteConvention>(); 

   ---

6. } 

   ---

7.  

   ---

Fluent API方式

1. public partial class User 

   ---

2. { 

   ---

3. public int UserID { get; set; } 

   ---

4. public string UserName { get; set; } 

   ---

5. public string Password { get; set; } 

   ---

6. public Nullable<bool> IsValid { get; set; } 

   ---

7.  

   ---

8. public virtual ICollection<Role> Roles { get; set; } 

   ---

9. } 

   ---

10. --------------------------------------------------------------------- 

    ---

11. public class UserMap : EntityTypeConfiguration<User> 

    ---

12. { 

    ---

13. public UserMap() 

    ---

14. { 

    ---

15. // Primary Key 

    ---

16. this.HasKey(t => t.UserID); 

    ---

17.  

    ---

18. // Properties 

    ---

19. this.Property(t => t.UserName) 

    ---

20. .HasMaxLength(50); 

    ---

21.  

    ---

22. this.Property(t => t.Password) 

    ---

23. .HasMaxLength(100); 

    ---

24.  

    ---

25. // Table & Column Mappings 

    ---

26. this.ToTable("User"); 

    ---

27. this.Property(t => t.UserID).HasColumnName("UserID"); 

    ---

28. this.Property(t => t.UserName).HasColumnName("UserName"); 

    ---

29. this.Property(t => t.Password).HasColumnName("Password"); 

    ---

30. this.Property(t => t.IsValid).HasColumnName("IsValid"); 

    ---

31. } 

    ---

32. } 

    ---

33. ---------------------------------------------------------------------------- 

    ---

34. public partial class Role 

    ---

35. { 

    ---

36. public int RoleID { get; set; } 

    ---

37. public string RoleName { get; set; } 

    ---

38.  

    ---

39. public virtual ICollection<User> Users { get; set; } 

    ---

40. } 

    ---

41. ----------------------------------------------------------------------------- 

    ---

42. public class RoleMap : EntityTypeConfiguration<Role> 

    ---

43. { 

    ---

44. public RoleMap() 

    ---

45. { 

    ---

46. // Primary Key 

    ---

47. this.HasKey(t => t.RoleID); 

    ---

48.  

    ---

49. // Properties 

    ---

50. this.Property(t => t.RoleName) 

    ---

51. .HasMaxLength(50); 

    ---

52.  

    ---

53. // Table & Column Mappings 

    ---

54. this.ToTable("Role"); 

    ---

55. this.Property(t => t.RoleID).HasColumnName("RoleID"); 

    ---

56. this.Property(t => t.RoleName).HasColumnName("RoleName"); 

    ---

57.  

    ---

58. // Relationships 

    ---

59. this.HasMany(t => t.Users) 

    ---

60. .WithMany(t => t.Roles) 

    ---

61. .Map(m => 

    ---

62. { 

    ---

63. m.ToTable("UserRole"); 

    ---

64. m.MapLeftKey("RoleID"); 

    ---

65. m.MapRightKey("UserID"); 

    ---

66. }); 

    ---

67. } 

    ---

68. } 

    ---

69.  

    ---

5.一对多自反关系

Fluent API方式

1. public class Category 

   ---

2. { 

   ---

3. public int CategoryID { get; set; } 

   ---

4. public int CategoryNo { get; set; } 

   ---

5. public string CategoryName { get; set; } 

   ---

6. public Nullable<int> ParentID { get; set; } 

   ---

7. public virtual Category Parent { get; set; } 

   ---

8. public virtual ICollection<Category> Children { get; set; } 

   ---

9. } 

   ---

10. --------------------------------------------------------------------- 

    ---

11. public class CategoryMap : EntityTypeConfiguration<Category> 

    ---

12. { 

    ---

13. public CategoryMap() 

    ---

14. { 

    ---

15. // Primary Key 

    ---

16. this.HasKey(t => t.CategoryID); 

    ---

17.  

    ---

18. // Properties 

    ---

19. this.Property(t => t.CategoryName) 

    ---

20. .IsRequired() 

    ---

21. .HasMaxLength(50); 

    ---

22.  

    ---

23. // Table & Column Mappings 

    ---

24. this.ToTable("Category"); 

    ---

25. this.Property(t => t.CategoryID).HasColumnName("CategoryID"); 

    ---

26. this.Property(t => t.CategoryNo).HasColumnName("CategoryNo"); 

    ---

27. this.Property(t => t.CategoryName).HasColumnName("CategoryName"); 

    ---

28. this.Property(t => t.ParentID).HasColumnName("ParentID"); 

    ---

29.  

    ---

30. // Relationships 

    ---

31. this.HasOptional(t => t.Parent) 

    ---

32. .WithMany(t => t.Children) 

    ---

33. .HasForeignKey(d => d.ParentID); 

    ---

34. } 

    ---

35. } 

    ---

6.多对多自反关系

Fluent API方式

1. /// <summary> 

   ---

2. /// Family表多对多自反关系 

   ---

3. /// </summary> 

   ---

4. public partial class Family 

   ---

5. { 

   ---

6. public Family() 

   ---

7. { 

   ---

8. this.Parents = new List<Family>(); 

   ---

9. this.Children = new List<Family>(); 

   ---

10. } 

    ---

11.  

    ---

12. public int FamilyID { get; set; } 

    ---

13. public string Name { get; set; } 

    ---

14. public Nullable<bool> Sex { get; set; } 

    ---

15. public Nullable<System.DateTime> Birthday { get; set; } 

    ---

16. public virtual ICollection<Family> Parents { get; set; } 

    ---

17. public virtual ICollection<Family> Children { get; set; } 

    ---

18. } 

    ---

19. --------------------------------------------------------------------- 

    ---

20. public class FamilyMap : EntityTypeConfiguration<Family> 

    ---

21. { 

    ---

22. public FamilyMap() 

    ---

23. { 

    ---

24. // Primary Key 

    ---

25. this.HasKey(t => t.FamilyID); 

    ---

26.  

    ---

27. // Properties 

    ---

28. this.Property(t => t.Name) 

    ---

29. .HasMaxLength(50); 

    ---

30.  

    ---

31. // Table & Column Mappings 

    ---

32. this.ToTable("Family"); 

    ---

33. this.Property(t => t.FamilyID).HasColumnName("FamilyID"); 

    ---

34. this.Property(t => t.Name).HasColumnName("Name"); 

    ---

35. this.Property(t => t.Sex).HasColumnName("Sex"); 

    ---

36. this.Property(t => t.Birthday).HasColumnName("Birthday"); 

    ---

37.  

    ---

38. // Relationships 

    ---

39. this.HasMany(t => t.Parents) 

    ---

40. .WithMany(t => t.Children) 

    ---

41. .Map(m => 

    ---

42. { 

    ---

43. m.ToTable("FamilyRelationship"); 

    ---

44. m.MapLeftKey("ParentID"); 

    ---

45. m.MapRightKey("ChildID"); 

    ---

46. }); 

    ---

47. } 

    ---

48. } 

    ---