EF_简单的增删改查-白红宇

EF_简单的增删改查

阅读量：5211 次

发布时间：2019-06-14

本文共 9887 字，大约阅读时间需要 32 分钟。

EF分为三种code_first,model_first，dabase_first这三种模式，网上的例子有好多，但是用了之后感觉实际中都不是这么用的，此处记录写下来日后用的着了可以快速应用，记录如下：

新建项目添加EF6.2

需要四个东西：

1.表对应的model实例，此例中为： shop_test

2.EF连接数据的对象类，此例中为： EF_DATA_DBCONTEXT

3.数据操作的接口类，此例中为： IRepository

4.数据实际操作类，实现接口IRespository的类，此例中为: DataAccessObject

1.shop_test

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.ComponentModel.DataAnnotations.Schema;

using System.ComponentModel.DataAnnotations;

using System.Runtime.Serialization;

namespace EF_TEST

{

[DataContract]

[Serializable]

[Table("shop_test")]

public partial class shop_test

{

[DataMember(Name ="id")]

[Key]

[DatabaseGenerated(DatabaseGeneratedOption.Identity)]

public int id { get; set; }

[DataMember(Name ="shopname")]

public string shopname { get; set; }

[DataMember(Name ="create_time")]

public DateTime create_time { get; set; }

[DataMember(Name ="test_msg")]

public string test_msg { get; set; }

}

2.EF_DATA_DBCONTEXT

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Data.Entity;

namespace EF_TEST

{

//用EF进行连接时需要指定的连接数据库的

class EF_DATA_DBCONTEXT:DbContext

{

public EF_DATA_DBCONTEXT(string contr) : base(contr)

{

}

protected override void OnModelCreating(DbModelBuilder modelBuilder)

{

//base.OnModelCreating(modelBuilder);

}

public DbSet<shop_test> shoptests { get; set; }

}

3.IRepository

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Linq.Expressions;

using System.Data.Entity;

using System.Data.Entity.Infrastructure;

namespace EF_TEST

{

interface IRepository

{

DbContext CurrentDbContext

{

get;

}

DbEntityEntry<T> Attach<T>(T entity) where T : class;

T Insert<T>(T entity) where T : class;

T Insert<T>(T entity, bool isCommit) where T : class;

void InsertRange<T>(IEnumerable<T> entities) where T : class;

void InsertRange<T>(IEnumerable<T> entities, bool isCommit) where T : class;

void Update<T>(T entity) where T : class;

void Update<T>(T entity, bool isCommit) where T : class;

void UpdateRange<T>(IEnumerable<T> entities) where T : class;

void UpdateRange<T>(IEnumerable<T> entities, bool isCommit) where T : class;

void Delete<T>(T entity) where T : class;

void Delete<T>(T entity, bool isCommit) where T : class;

void DeleteRange<T>(IEnumerable<T> entities) where T : class;

void DeleteRange<T>(IEnumerable<T> entities, bool isCommit) where T : class;

T Find<T>(params object[] keyValues) where T : class;

T Find<T>(object keyValue) where T : class;

List<T> FindAll<T>(Expression<Func<T, bool>> conditions = null) where T : class;

List<T> FindAllByPage<T, S>(Expression<Func<T, bool>> conditions, Expression<Func<T, S>> orderBy, int pageSize, int pageIndex) where T : class;

int SaveChanges();

}

4.DataAccessObject

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Data.Entity;

using System.Linq.Expressions;

using System.Data.Entity.Infrastructure;

using System.Data;

namespace EF_TEST

{

class DataAccessObject:IRepository,IDisposable

{

private DbContext _currentDbContext = null;

public DbContext CurrentDbContext

{

get

{

return this._currentDbContext;

}

public DataAccessObject(DbContext dbContext)

{

this._currentDbContext = dbContext;

}

public DbEntityEntry<T> Attach<T>(T entity) where T : class

{

DbSet<T> dbSet = this._currentDbContext.Set<T>();

dbSet.Attach(entity);

return this._currentDbContext.Entry<T>(entity);

}

public T Insert<T>(T entity) where T : class

{

return this.Insert<T>(entity, true);

}

public T Insert<T>(T entity, bool isCommit) where T : class

{

this._currentDbContext.Set<T>().Add(entity);

if (isCommit)

{

this._currentDbContext.SaveChanges();

}

return entity;

}

public void InsertRange<T>(IEnumerable<T> entities) where T : class

{

this.InsertRange<T>(entities, true);

}

public void InsertRange<T>(IEnumerable<T> entities, bool isCommit) where T : class

{

this._currentDbContext.Set<T>().AddRange(entities);

if (isCommit)

{

this._currentDbContext.SaveChanges();

}

public void Update<T>(T entity) where T : class

{

this.Update<T>(entity, true);

}

public void Update<T>(T entity, bool isCommit) where T : class

{

this._currentDbContext.Set<T>().Attach(entity);

//this._currentDbContext.Entry<T>(entity).set_State(16);

this._currentDbContext.Entry<T>(entity).State = EntityState.Modified;

if (isCommit)

{

this._currentDbContext.SaveChanges();

}

public void UpdateRange<T>(IEnumerable<T> entities) where T : class

{

this.UpdateRange<T>(entities, true);

}

public void UpdateRange<T>(IEnumerable<T> entities, bool isCommit) where T : class

{

foreach (T current in entities)

{

this._currentDbContext.Set<T>().Attach(current);

// this._currentDbContext.Entry<T>(current).set_State(16);

this._currentDbContext.Entry<T>(current).State = EntityState.Modified;

}

if (isCommit)

{

this._currentDbContext.SaveChanges();

}

public void Delete<T>(T entity) where T : class

{

this.Delete<T>(entity, true);

}

public void Delete<T>(T entity, bool isCommit) where T : class

{

this._currentDbContext.Set<T>().Remove(entity);

if (isCommit)

{

this._currentDbContext.SaveChanges();

}

public void DeleteRange<T>(IEnumerable<T> entities) where T : class

{

this.DeleteRange<T>(entities, true);

}

public void DeleteRange<T>(IEnumerable<T> entities, bool isCommit) where T : class

{

this._currentDbContext.Set<T>().RemoveRange(entities);

if (isCommit)

{

this._currentDbContext.SaveChanges();

}

public int SaveChanges()

{

return this._currentDbContext.SaveChanges();

}

public T Find<T>(params object[] keyValues) where T : class

{

return this._currentDbContext.Set<T>().Find(keyValues);

}

public T Find<T>(object keyValue) where T : class

{

object[] array = new object[]

{

keyValue

};

return this._currentDbContext.Set<T>().Find(array);

}

public List<T> FindAll<T>(Expression<Func<T, bool>> conditions = null) where T : class

{

List<T> result;

if (conditions == null)

{

result = this._currentDbContext.Set<T>().ToList<T>();

}

else

{

result = this._currentDbContext.Set<T>().Where(conditions).ToList<T>();

}

return result;

}

public List<T> FindAllByPage<T, S>(Expression<Func<T, bool>> conditions, Expression<Func<T, S>> orderBy, int pageSize, int pageIndex) where T : class

{

IQueryable<T> source = (conditions == null) ? this._currentDbContext.Set<T>() : this._currentDbContext.Set<T>().Where(conditions);

return source.OrderByDescending(orderBy).Skip((pageIndex - 1) * pageSize).Take(pageSize).ToList<T>();

}

public void Dispose()

{

this._currentDbContext.Dispose();

}

控制台程序：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Data.Entity;

using System.Transactions;

namespace EF_TEST

{

class Program

{

static void Main(string[] args)

{

//config中的数据库的连接字符串

string CONSTR = System.Configuration.ConfigurationManager.ConnectionStrings["CONSTR"].ConnectionString;

//EF的DB连接对象

EF_DATA_DBCONTEXT db = new EF_DATA_DBCONTEXT(CONSTR);

//实现的的具体方法

IRepository DB_LINK = new DataAccessObject(db);

//进行的查询操作

List<shop_test> msg = DB_LINK.FindAll<shop_test>(p => p.id >= 0);

Console.WriteLine("查询ID大于0的所有数据");

Console.WriteLine("共查询到的信息行数:{0}--最后一个数据的时间:{1}", msg.Count, msg.Max(u => u.create_time).ToString());

//插入操作

shop_test insert_shop = new shop_test() { shopname="test", test_msg="ss", create_time =DateTime.Now };

using (TransactionScope scope =new TransactionScope() )

{

DB_LINK.Insert<shop_test>(insert_shop,false);

shop_test insert_second = new shop_test() { shopname=insert_shop.shopname, test_msg=insert_shop.test_msg, create_time=DateTime.Now };

DB_LINK.Insert<shop_test>(insert_second, false);

DB_LINK.SaveChanges();

scope.Complete();

}

Console.WriteLine("插入的id:{0}--shopname {1}---test_msg:{2} ---create_time:{2}", insert_shop.id, insert_shop.shopname, insert_shop.test_msg, insert_shop.create_time);

//更新操作

msg = DB_LINK.FindAll<shop_test>(u => u.id > 0);

Console.WriteLine("查询ID大于0的所有数据");

Console.WriteLine("共查询到的信息行数:{0}--最后一个数据的时间:{1}", msg.Count, msg.Max(u => u.create_time));

//更新操作，更新最大时间为当前时间

shop_test update_shop = (from i in msg

let max_time = msg.Max(u => u.create_time)

where i.create_time == max_time

select i

).FirstOrDefault();

update_shop.create_time = DateTime.Now;

DB_LINK.Update<shop_test>(update_shop);

Console.WriteLine("更新的id:{0}--shopname {1}---test_msg:{2} ---create_time:{2}", insert_shop.id, insert_shop.shopname, insert_shop.test_msg, insert_shop.create_time);

//删除操作；

Console.WriteLine("查询ID大于0的所有数据");

Console.WriteLine("共查询到的信息行数:{0}--最后一个数据的时间:{1}", msg.Count, msg.Max(u => u.create_time));

//删除操作删除时间最早的数据

msg = DB_LINK.FindAll<shop_test>(u => u.id > 0);

shop_test delete_shop = (from i in msg

let max_time = msg.Max(u => u.create_time)

where i.create_time == max_time

select i

).FirstOrDefault();

DB_LINK.Delete<shop_test>(delete_shop);

Console.WriteLine("删除的id:{0}--shopname {1}---test_msg:{2} ---create_time:{2}", insert_shop.id, insert_shop.shopname, insert_shop.test_msg, insert_shop.create_time);

Console.WriteLine("查询ID大于0的所有数据");

Console.WriteLine("共查询到的信息行数:{0}--最后一个数据的时间:{1}", msg.Count, msg.Max(u=>u.create_time));

Console.ReadKey();

}

配置文件，及其数据库的表结构：

</connectionStrings>

CREATE TABLE [dbo].[shop_test](

[id] [INT] IDENTITY(1,1) NOT NULL,

[shopname] [VARCHAR](50) NULL,

[create_time] [DATETIME] NULL,

CONSTRAINT [PK_shop_test] PRIMARY KEY NONCLUSTERED