using System.Data.Entity.ModelConfiguration.Configuration;
namespace CodeFirst_FluentAPI_Tutorials
{
public class SchoolContext: DbContext
{
public SchoolDBContext(): base()
{
}
public DbSet<Student> Students { get; set; }
public DbSet<Standard> Standards { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Student>().Map(delegate(EntityMappingConfiguration<Student> studentConfig)
{
studentConfig.Properties(p => new { p.StudentId, p.StudentName });
studentConfig.ToTable("StudentInfo");
});
Action<EntityMappingConfiguration<Student>> studentMapping = m =>
{
m.Properties(p => new { p.StudentId, p.Height, p.Weight, p.Photo, p.DateOfBirth });
m.ToTable("StudentInfoDetail");
};
modelBuilder.Entity<Student>().Map(studentMapping);
modelBuilder.Entity<Standard>().ToTable("StandardInfo");
}
}
}
目录
实体特性（Data Annonation 标注）： 将实体映射到数据表格。
Data Annonation & FluentApi
Data Annonation Attributes
Table
Column
Key
NotMapped
ForeignKey
Index
InverseProperty todo
Required
MaxLength MinLength
StringLength
TimeStamp
DatabaseGenerated
ConcurrencyCheck
Fluent Api
实体映射
属性映射
————————————————
案例
[Table("StudentInfo")]
public class Student
{
public Student() { }
[Key]
public int SID { get; set; }
[Column("Name", TypeName="text")] //对应数据库的中列
[MaxLength(20)]
public string StudentName { get; set; }
[NotMapped]
public int? Age { get; set; }
public int StdId { get; set; }
[ForeignKey("StdId")]
public virtual Standard Standard { get; set; }
}
实体特性（Data Annonation 标注）详解
Table
Table(string name,Properties:[Schema=string])
name:db table name
Schema:要创建的表的架构
如果没有指定些特性，将创建默认的表Students or Studentes
格式：(TableName+‘s’(or ‘es’)
如果指定则按指定的名创建
[Table("StudentInfo")]//将Student实体映射到数据库中的StudentInfo表格
public class Student
{
}
using System.ComponentModel.DataAnnotations.Schema;
[Table("StudentMaster", Schema="Admin")]
public class Student
{
public int StudentID { get; set; }
public string StudentName { get; set; }
}
Column
[Column(string name,Properties:[Order=int],[TypeName=string])
- 列名: Name of a column in a db table.
- 列索引: Order of a column, starting with zero index. (可选)
- TypeName: Data type of a column. (可选)
索引从0开始，并且不能有重复索引
public class Student
{
public int StudentID { get; set; }
[Column("Name")]
public string StudentName { get; set; }
[Column("DoB", TypeName="DateTime2")]
public DateTime DateOfBirth { get; set; }
public byte[] Photo { get; set; }
public decimal Height { get; set; }
public float Weight { get; set; }
}
列的排序
using System.ComponentModel.DataAnnotations.Schema;
public class Student
{
[Column(Order = 0)]
public int StudentID { get; set; }
[Column("Name", Order = 1)]
public string StudentName { get; set; }
[Column("DoB", Order = 5)]
public DateTime DateOfBirth { get; set; }
[Column(Order = 3)]
public byte[] Photo { get; set; }
[Column(Order = 2)]
public decimal Height { get; set; }
[Column(Order = 4)]
public float Weight { get; set; }
}
Key 主键
下面的为组合主键
public class Student
{
[Key]
[Column(Order=1)]
public int StudentId{get;set;}
[Key]
[Column(Order=2)]
public string StudentName
}
ForeignKey 外键
Index 索引
[Index("IndexName,IsClustered=true,IsUnique=true)]
public int OrderNumber{get;set;}
Required
必输选项Not Null Column Required
public class Student
{
public int StudentID { get; set; }
[Required]//对应的数据库列不能为空null
public string StudentName { get; set; }
}
MaxLength MinLength
C#中对应类型可以string 或 byte[]
using System.ComponentModel.DataAnnotations;
public class Student
{
public int StudentID { get; set; }
[MaxLength(50)]
public string StudentName { get; set; }
}
StringLength
可变长度 nvarchar(50)
[StringLength(50)]
public string Name{get;set;}
public string Name{get;set;}
sqlserver中，将转为数据库中的nvarchar(max)
mysql转为longtext
加上
[MaxLength]转为varchar(50)
[MinLength(50)]转为longtext
[StringLength(50)]也是转为varchar(50) ,
using System.ComponentModel.DataAnnotations;
public class Student
{
public int StudentID { get; set; }
[StringLength(50)]
public string StudentName { get; set; }
}
NotMapped 特性
不映射实体的属性到数据库表格中的列。
[NotMpaaed]
public string StudentName { get; set; }
// 此列不会在数据库中创建相关的列。
///如果属性只有get或set，也不会创建相关列。如下：
public int Age { get { return _age; } }
public double Height { set { _height = value; } }
DatabaseGenerated
- 1.DatabaseGeneratedOption.None
自己输入值，不用数据库生成的
public class Course
{
[DatabaseGenerated(DatabaseGeneratedOption.None)]
public int CourseId { get; set; }
public string CourseName { get; set; }
}
/* ef core api 中配置
modelBuilder.Entity<Course>()
.Property(p => p.CourseId)
.ValueGeneratedNever();
*/
2.DatabaseGeneratedOption.Identity
根据具体的数据库来生成，插入后值不可更新。
有identity rowversion guid 等
public class Course
{
public int CourseId { get; set; }
public string CourseName { get; set; }
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int RecordNum { get; set; }
}
/* ef core api
modelBuilder.Entity<Course>().Property(p=>p.CourseId).ValueGeneratedOnAdd();
*/
3.DatabaseGeneratedOption.Computed
在插入或更新的时候来设置值，需要我们自己计算的值
public class Student
{
public int StudentID { get; set; }
public string StudentName { get; set; }
public DateTime? DateOfBirth { get; set; }
public decimal Height { get; set; }
public float Weight { get; set; }
[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
public DateTime CreatedDate { get; set; }
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entry<Student>().Property(s=>s.CreateDate)
.HasDefaultValueSql("GETDATE()");
//这个是调用sqlserver的函数来设置它的值 没有试
}
ConcurrencyCheck
concurrencycheck与timestamp区别
concurrencycheck可用于多个属性的任意数据类型的检测
timestamp只可用于一个byte[]类型属性的检测,一个实体中只可有一个此类型
public class Student
{
[Key]
public int Sid { get; set; }
[ConcurrencyCheck]
public string Sname { get; set; }
//[Timestamp] mysql中无效
public byte[] RowVersion;
public virtual StudentAddress Address { get; set; }
}
TimeStamp
一个实体类中只可有一个类型为TimeStamp，用于并发检测
[TimeStamp]，SQLServer中是这样，但是没有装，我也没试。在MySql中，此法无效。需要加入ConCurrencyCheck
public byte[] TimeStamp{get;set;}
参考
在mysql中如果将属性设置为[Timestamp]将报错。
在这里插入图片描述
public class Student
{
[Key]
public int Sid { get; set; }
[ConcurrencyCheck]
public string Sname { get; set; }
//[Timestamp] mysql中无效
public byte[] RowVersion;
public virtual StudentAddress Address { get; set; }
}
Fluent Api
实体映射
public class SchoolDBContext: DbContext
{
public SchoolDBContext(): base("SchoolDBConnectionString")
{
}
public DbSet<Student> Students { get; set; }
public DbSet<Standard> Standards { get; set; }
public DbSet<StudentAddress> StudentAddress { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
//Configure domain classes using modelBuilder here..
//config default schema
modelBuilder.HasDefaultSchema("Admin");
//map entity to table
modelBuilder.Entity<Student>().ToTable("StudentInfo");
modelBuilder.Entit<Student>().ToTable("StandardInfo","dbo");
//map to multiple tables
modelBuilder.Entity<Student>().Map(m=>
{
m.Properties(p=>new {p.StudentId,p.StudentName});
m.ToTable("StudentInfo");
}).Map(m=>
{
m.Properties(p=>new {p.StudentId,p.Height,p.Weight,p.Photo});
m.ToTable("StudentInfoDetail");
});
modelBuilder.Entity<Standard>().ToTable("StandardInfo");
}
}
将一个表分割为2个表
也可使用委托或表达式
using System.Data.Entity.ModelConfiguration.Configuration;
namespace CodeFirst_FluentAPI_Tutorials
{
public class SchoolContext: DbContext
{
public SchoolDBContext(): base()
{
}
public DbSet<Student> Students { get; set; }
public DbSet<Standard> Standards { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Student>().Map(delegate(EntityMappingConfiguration<Student> studentConfig)
{
studentConfig.Properties(p => new { p.StudentId, p.StudentName });
studentConfig.ToTable("StudentInfo");
});
Action<EntityMappingConfiguration<Student>> studentMapping = m =>
{
m.Properties(p => new { p.StudentId, p.Height, p.Weight, p.Photo, p.DateOfBirth });
m.ToTable("StudentInfoDetail");
};
modelBuilder.Entity<Student>().Map(studentMapping);
modelBuilder.Entity<Standard>().ToTable("StandardInfo");
}
}
}
属性映射
ublic class SchoolContext: DbContext
{
public SchoolDBContext(): base()
{
}
public DbSet<Student> Students { get; set; }
public DbSet<Standard> Standards { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
//Configure primary key
modelBuilder.Entity<Student>().HasKey<int>(s => s.StudentKey);
modelBuilder.Entity<Standard>().HasKey<int>(s => s.StandardKey);
//Configure composite primary key
modelBuilder.Entity<Student>().HasKey<int>(s => new { s.StudentKey, s.StudentName });
//config column
modelBuilder.Entity<Student>()
.Property(p=>p.DataofBirth)
.HasColumn("DoB")
.HasColumnOrder(3)
.HasColumnType("datetime2")
.IsOption() //null
.IsRequired()//not null
.HasMaxLength(50)
.HasMaxLength(50).IsFixedLength()//change type from nvarchar to nchar
.HasPrecision(2,2) //set size decimal(2,2)
.IsCurrencyToken()//concurrency check
.IsRowVersion()//timestamp type byte[] make it as concurrency column
;
}
}
C# 数据类型和对应的SQL Sever数据类型.
| C# Data Type | Mapping to SQL Server Data Type |
|---|---|
| int | int |
| string | nvarchar(Max) |
| decimal | decimal(18,2) |
| float | real |
| byte[] | varbinary(Max) |
| datetime | datetime |
| bool | bit |
| byte | tinyint |
| short | smallint |
| long | bigint |
| double | float |
| char | No mapping |
| sbyte | No mapping (throws exception) |
| object | No mapping |