对于新的EF项目,EntityTypeConfiguration和DbMigration之间有什么区别? [英] What is the difference between EntityTypeConfiguration and DbMigration for a new EF project
问题描述
EntityTypeConfiguration
构建我的数据模型,或者我应该直接启用迁移使用 DbMigration
。 这是使用:
public class BlogEFCFConfiguration:EntityTypeConfiguration< Blog> {
public BlogEFCFConfiguration()
:base(){
HasKey(x => x.BlogId);
属性(x => x.BlogId).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
属性(x => x.Name).HasColumnType(varchar)。HasMaxLength(128);
}
}
或
public partial class InitialCreate:DbMigration {
public override void Up(){
CreateTable(
dbo.Blogs,
c => new
{
BlogId = c.Int(nullable:false,identity:true),
Name = c.String(maxLength:128,unicode:false),
})
.PrimaryKey(t => t.BlogId);
}
public override void Down(){
DropTable(dbo.Blogs);
}
}
的确,如果我想改变我的模型,我会有最后使用 DbMigration
。那么为什么要使用 EntityTypeConfiguration
?
这可能是一个太开放的问题。
他们正在做不同的工作 - EF迁移确保应用程序和数据库更改是一致的。配置通知EF如何从对象模型映射到关系模型。
如果默认约定不适合您的型号,则需要配置。
如果您需要EF迁移希望在应用程序版本之间的代码中对数据库进行更改。这具有能够自动使应用程序在启动时将数据库更新到最新版本的优点。
Should I use EntityTypeConfiguration
to build my data model, or should I directly enable migrations an use DbMigration
.
That is use :
public class BlogEFCFConfiguration : EntityTypeConfiguration<Blog> {
public BlogEFCFConfiguration()
: base() {
HasKey(x => x.BlogId);
Property(x => x.BlogId).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
Property(x => x.Name).HasColumnType("varchar").HasMaxLength(128);
}
}
or
public partial class InitialCreate : DbMigration {
public override void Up() {
CreateTable(
"dbo.Blogs",
c => new
{
BlogId = c.Int(nullable: false, identity: true),
Name = c.String(maxLength: 128, unicode: false),
})
.PrimaryKey(t => t.BlogId);
}
public override void Down() {
DropTable("dbo.Blogs");
}
}
Indeed if I want to change my model I will have to finally use DbMigration
. So why use EntityTypeConfiguration
?
It is may be a too open question.
They are doing different jobs - EF migrations ensure that the application and database changes are aligned. The configurations inform EF how to map from your object model to your relational model.
Configurations are required when the default conventions don't suit your model.
EF migrations are required if you wish to model the database changes in code between application versions. This has the advantage of being able to automatically have the application update the database to the latest version on startup for example.
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