EFCodeFirst属性映射约定

EFCodeFirst属性映射约定

EFCodeFirst

属性映射约定

CodeFirst与数据表之间得映射方式又两种:Data Annotation和Fluent API
默认约定：

表名为类名的复数。
创建表得所有者为dbo。

int类型属性映射成数据库int类型。
string类型属性映射成数据库NVARCHAR类型。
若类的字符串类型属性未设置MaxLength，则生成对应的列类型为NVARCHAR(MAX)。

默认主键约束：属性名为[ID]或[类名 + ID]

对于int类型主键，会自动增长。

1 自定义映射表名以及所有者

Data Annotation

1. //必要引用 

   ---

2. using System.ComponentModel.DataAnnotations.Schema; 

   ---

3. //映射表名 

   ---

4. [Table("Product")] 

   ---

5. public class Product 

   ---

6. //映射表名以及所有者 

   ---

7. [Table("Product", Schema = "dbo")] 

   ---

8. public class Product 

   ---

Fluent API方式

1. //重写OnModelCreating方法实现 映射表名 

   ---

2. protected override void OnModelCreating(DbModelBuilder modelBuilder) 

   ---

3. { 

   ---

4. modelBuilder.Entity<Product>().ToTable("Product"); 

   ---

5. } 

   ---

6. //重写OnModelCreating方法实现 映射表名以及所有者 

   ---

7. protected override void OnModelCreating(DbModelBuilder modelBuilder) 

   ---

8. { 

   ---

9. modelBuilder.Entity<Product>().ToTable("Product", "dbo"); 

   ---

10. } 

    ---

2.字段名、长度、数据类型及是否可空

Data Annotation

1. //映射列名 

   ---

2. [Column("ProductID")] 

   ---

3. public int ProductID { get; set; } 

   ---

4. //映射列名，长度，是否为空 

   ---

5. [MaxLength(100)] 

   ---

6. [Required, Column("ProductName")] 

   ---

7. public string ProductName { get; set; } 

   ---

8. //指定映射的数据类型 

   ---

9. [Column("UnitPrice", TypeName = "MONEY")] 

   ---

10. public decimal UnitPrice { get; set; } 

    ---

11. //设置Text 

    ---

12. [Column("Remark", TypeName = "text")] 

    ---

13. public string Remark { get; set; } 

    ---

Fluent API方式

1. protected override void OnModelCreating(DbModelBuilder modelBuilder) 

   ---

2. { 

   ---

3. //映射列名 

   ---

4. modelBuilder.Entity<Product>().Property(t => t.ProductID) 

   ---

5. .HasColumnName("ProductID"); 

   ---

6. //映射列名，是否为空，最大长度 

   ---

7. modelBuilder.Entity<Product>().Property(t => t.ProductName) 

   ---

8. .IsRequired() 

   ---

9. .HasColumnName("ProductName") 

   ---

10. 　　　　 .HasMaxLength(100); 

    ---

11. } 

    ---

12. //指定映射的数据类型 

    ---

13. modelBuilder.Entity<Product>().Property(t => t.UnitPrice) 

    ---

14. .HasColumnName("UnitPrice") 

    ---

15. .HasColumnType("MONEY"); 

    ---

16. //设置Text 

    ---

17. modelBuilder.Entity<Category>().Property(t => t.Remark) 

    ---

18. .HasColumnName("Remark") 

    ---

19. .HasColumnType("text"); 

    ---

3.主键

Data Annotation

1. [Key] 

   ---

2. [Column("ProductID")] 

   ---

3. public int ProductID { get; set; } 

   ---

Fluent API方式

1. protected override void OnModelCreating(DbModelBuilder modelBuilder) 

   ---

2. { 

   ---

3. modelBuilder.Entity<Product>().HasKey(t => t.ProductID); 

   ---

4. } 

   ---

5. //多主键 

   ---

6. protected override void OnModelCreating(DbModelBuilder modelBuilder) 

   ---

7. { 

   ---

8. modelBuilder.Entity<Product>().HasKey(t => new { t.KeyID, t.CandidateID }); 

   ---

9. } 

   ---

4.数据库自动生成字段值

Data Annotation

1. //取消int类型主键自动增长 

   ---

2. [Key] 

   ---

3. [Column("ProductID")] 

   ---

4. [DatabaseGenerated(DatabaseGeneratedOption.None)] 

   ---

5. public int ProductID { get; set; } 

   ---

6. [Key] 

   ---

7. [Column("CategoryID")] 

   ---

8. [DatabaseGenerated(DatabaseGeneratedOption.Identity)] 

   ---

9. public int CategoryID { get; set; } 

   ---

Fluent API方式

1. //取消int类型主键自动增长 

   ---

2. protected override void OnModelCreating(DbModelBuilder modelBuilder) 

   ---

3. { 

   ---

4. modelBuilder.Entity<Product>().HasKey(t => t.ProductID); 

   ---

5. modelBuilder.Entity<Product>().Property(t => t.ProductID) 

   ---

6. .HasColumnName("ProductID") 

   ---

7. .HasDatabaseGeneratedOption(DatabaseGeneratedOption.None); 

   ---

8. } 

   ---

9. modelBuilder.Entity<Category>().ToTable("Category", "dbo"); 

   ---

10. modelBuilder.Entity<Category>().HasKey(t => t.CategoryID); 

    ---

11. modelBuilder.Entity<Category>().Property(t => t.CategoryID) 

    ---

12. .HasColumnName("CategoryID") 

    ---

13. .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity); 

    ---

14. } 

    ---

5.数字类型长度及精度

Fluent API方式

1. protected override void OnModelCreating(DbModelBuilder modelBuilder) 

   ---

2. { 

   ---

3. modelBuilder.Entity<Product>().Property(t => t.UnitPrice) 

   ---

4. .HasColumnName("UnitPrice") 

   ---

5. .HasPrecision(18, 2); 

   ---

6. } 

   ---

6.非数据库字段属性

Data Annotation

1. [NotMapped] 

   ---

2. public string Remark { get; set; } 

   ---

Fluent API方式

1. protected override void OnModelCreating(DbModelBuilder modelBuilder) 

   ---

2. { 

   ---

3. modelBuilder.Entity<Product>().Ignore(t => t.Remark); 

   ---

4. } 

   ---

7.Fluent API配置Configuration映射类

方便维护

1. using System; 

   ---

2. using System.Collections.Generic; 

   ---

3. using System.Linq; 

   ---

4. using System.Text; 

   ---

5.  

   ---

6. using System.ComponentModel.DataAnnotations.Schema; 

   ---

7. using System.Data.Entity.ModelConfiguration; 

   ---

8.  

   ---

9. using Portal.Entities; 

   ---

10.  

    ---

11. namespace Portal.Mapping 

    ---

12. { 

    ---

13. public class ProductMap : EntityTypeConfiguration<Product> 

    ---

14. { 

    ---

15. public ProductMap() 

    ---

16. { 

    ---

17. // Primary Key 

    ---

18. this.HasKey(t => t.ProductID); 

    ---

19.  

    ---

20. // Properties 

    ---

21. this.Property(t => t.ProductID) 

    ---

22. .HasDatabaseGeneratedOption(DatabaseGeneratedOption.None); 

    ---

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

    ---

24. .IsRequired() 

    ---

25. .HasMaxLength(100); 

    ---

26.  

    ---

27. // Table & Column Mappings 

    ---

28. this.ToTable("Product"); 

    ---

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

    ---

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

    ---

31. this.Property(t => t.UnitPrice) 

    ---

32. .HasColumnName("UnitPrice") 

    ---

33. .HasPrecision(18, 2); 

    ---

34. } 

    ---

35. } 

    ---

36. } 

    ---

1. protected override void OnModelCreating(DbModelBuilder modelBuilder) 

   ---

2. { 

   ---

3. modelBuilder.Configurations.Add(new ProductMap()); 

   ---

4. } 

   ---