soul.extensions.entityframework增强efcore

开发的初衷

　　由于ef提供的api主要是基于实体操作，如果我们想根据一个指定条件去更新实体和删除实体，势必存在性能问题。习惯了linq在去手写sql显然内心是拒绝和绝望的！！！

已经开发好基本的api并在github开源，开发是面向所有orm的，你只需要实现IMetadataProvider这个接口就可以将linq移植到类似dapper这种orm上面，语法风格部分借鉴sqlsugar，这里欢迎大家一起。

加入完善。

开源地址

　　1448376744/Soul.Extensions.EntityFrameworkCore: Soul.Extensions.EntityFrameworkCore (github.com)

使用方式

1. 继承

public class MyDbContext : SoulDbContext
{

}

2. 实现接口

public class SoulDbContext : DbContext, ISoulDbContext
{
    public IDbContextBehavior SoulContextBehavior { get; } = new DbContextBehavior();

    public IMetadataProvider MetadataProvider { get; private set; } 

    public SoulDbContext()
    {
        MetadataProvider = new EntityFrameworkMetadataProvider(Model,Database.ProviderName);
    }

    public SoulDbContext(IDbContextBehavior contextBehavior)
    {
        SoulContextBehavior = contextBehavior;
        MetadataProvider = new EntityFrameworkMetadataProvider(Model, Database.ProviderName);
    }

    public SoulDbContext(DbContextOptions options)
        : base(options)
    {
        MetadataProvider = new EntityFrameworkMetadataProvider(Model, Database.ProviderName);
    }

    public SoulDbContext(DbContextOptions options, IDbContextBehavior contextBehavior)
        : base(options)
    {
        SoulContextBehavior = contextBehavior;
        MetadataProvider = new EntityFrameworkMetadataProvider(Model, Database.ProviderName);
    }
}

原生sql支持

var row = context.Execuet("delete from student id = 1");

//支持类似dapper的参数格式，具体查看源码
var list = context.Query<Student>("select * from student where Id = @Id",new {Id = 1});

基于命令更新

1. insert

 //有这个api就不需要使用AutoMapper了
 var dto = new {Age = 3};
 context.Insert<Student>(dto)   
    .Execute();

//设置默认值
context.Insertable<Student>(new {Age = 3}) 
    .Initialize(c=>
    {
        //有了这个就可以设置一些不用在swagger显示的值了
        c.Add(nameof(Studen.CreateTime),DateTime.Now);
    })
    .Execute();

2. update

var context = new DbContext();
    context.Updateable<Student>()
    .Set(a=>a.Name,"zs")
    .Set(a=>a.Age,a=>a.Age+1)
    .Where(a=>a.Id>1)
    .Execute();

context.Updateable<Student>(new {Age = 3}) 
    .Initialize(c=>
    {
        //有了这个就可以设置一些不用在swagger显示的值了
        c.Add(nameof(Studen.Id),_identityServer.Id);
    })
    .Execute();

3. delete

context.Deleteable<Student>()
    .Where(a=>a.Id>1)
    .Execute();

扩展查询

1. 基本结构

//基本结构
var data = await context.Queryable<Student>()
    .Where(a => a.Id > 0)
    .GroupBy(a => a.Name)
    .Having(a => SqlFun.Count(a.Id) > 1)
    .Select(s => new 
    {
        s.Name,
        Count= SqlFun.Count(s.Id),
    })
    .SingleOrDefaultAsync();

2. 调用函数

var sum = awiat context.Queryable<Student>()
    .Select(s=>SqlFun.SUM(s.Age))
    .SingleOrDefaultAsync();

3. 计数查询

 var count = context.Queryable<Student>()
    .Count();

4. 带有表达式的函数

var list = awiat context.Queryable<Student>()
    .Select(s=>SqlFun.SUM(SqlFun.IF(a.Gender>0,s.Age,0)))
    .ToListAsync();

5. casewhen

//case
  var list = context.Queryable<Student>()
    .Where(a => a.Id > 401)
    .Select(s => new
    {
        ShowGender = SqlFun.Case<int>(
            new { When = s.Gender = 0, Then = "男" },
            new { When = s.Gender = 1, Then = "女" },
            new { Else = "其他" })
    })
    .ToList();

6. 多表连接查询

var list = context.Queryable<Student,School>((a, b) => new JoinExpression(JoinType.Inner, a.SchoolId==b.Id))
    .Select((a, b)=new
    {
        a.Id
        a.Name
        b.SchoolName
    })
    .ToList();

自定义函数

[Function]
public class SqlFun
{
    //case when
    [CaseWhen]
    public static TSource Case<TSource>(params object[] expressions)
    {
        throw new NotImplementedException();
    }
    //重命名
    [Function("FIND_IN_SET")]
    public static int IndexOf(int s1,int s2)
    {
        //该函数并不会被执行          
        throw new NotImplementedException();
    }
    public static TSource SUM<TSource>(TSource source)
    {
        //该函数并不会被执行          
        throw new NotImplementedException();
    }
    public static TSource IF<TSource>(object expression,TSource source1,TSource source2)
    {
        //该函数并不会被执行          
        throw new NotImplementedException();
    }
}

//使用
context.From<Student>()
.Where(a=>SqlFunc.IndexOf('2',a.Name)>0)
.Delete();