ORM之四：调用入口与调用示例

一、ORM入口封装

　 结合上一篇文章与这里的DbProvider().Init()方法，就很明显的知道了是创建一个mssql的实例。那么在DbService的泛型方法中显示提供了单表操作与多表linq查询的入口，其实还存在获取数据库扩展操作的入口。

public  class DbService
{
/// <summary>
/// 默认业务数据库的Provider
/// </summary>
public static IDbProvider DefaultProvider
{
get
{
return new DbProvider().Init(new DbConnInfo()
{
CommandTimeout = 60,
ConnectionString = "Data Source = 127.0.0.1;Initial Catalog =DapperData;uid=sa;pwd=sa123456;",
Provider = ProviderInfo.SqlServer,
DbKey = "DapperData"
});
}
}
}

public class DbService<T> where T : class,new()
{
/// <summary>
/// 默认数据库的DAL
/// </summary>
public static IReqository<T> Reqository
{
get
{
return DbService.DefaultProvider.GetReqository<T>();
}
}

/// <summary>
/// 主库指定类型的查询接口，是Linq的入口
/// </summary>
public static IQuery<T> Query
{
get
{
return DbService.DefaultProvider.GetQuery<T>();
}
}
}

二、单表、多表、扩展示例

　　A、单表

DbService<UserEntity>.Reqository.Single(w => w.Email.Contains("@"));
DbService<UserEntity>.Reqository.Insert(new UserEntity(){});
DbService<UserEntity>.Reqository.Update(up => new UserEntity{Email = "taibai@xingguangju.com"}, wh => wh.UserId == 4);
DbService<UserRoleEntity>.Reqository.Delete(w => w.Id == 4);

　　

　　B、多表连个查询

var resultList = (from u in DbService<UserEntity>.Query
join ur in DbService<UserRoleEntity>.Query on new {u = u.UserId, a = u.IsActive} equals
new {u = ur.UserId, a = ur.IsActive}
join r in DbService<RoleEntity>.Query on ur.RoleId equals r.RoleId
where u.UserId == 1
orderby u.UserId
select new UUR
{
UserId = u.UserId,
Username = u.Username,
PhoneNumber = u.PhoneNumber,
RoleName = r.RoleName
}).SetJoinMode(JoinMode.Inner, JoinMode.Inner).Page(1,1);

var result = resultList.ToList().FirstOrDefault();

　　C、分组查询

//select CICUser.UserId,
//       MAX([CICUserScore].[score])
//from [CICUser] Join [CICUserScore] on [CICUser].[UserId] = [CICUserScore].[UserId]
//group by CICUser.UserId having (SUM(CICUserScore.score) > 200)

var resultList = (from a in DbService<UserEntity>.Query
　　join b in DbService<UserScoreEntity>.Query on a.UserId equals b.UserId
　　group new {a, b} by new {a.UserId}
　　 into g
　　where g.Sum(m=>m.b.score)>200
　　select new
　{
　　userId= g.Key.UserId,
　　TotalScore = g.Max(b => b.b.score)
　}).ToList();

　　D、存储过程

var dbParameters = new DbParameterCollection();

dbParameters.Add(new DbParameter
{
DbType = DbType.Int32,
Name = "UserId",
Value =1,
Direction = ParameterDirection.Input
});

var resultList = DbService.DbExtension.ExcuteProcReader<UserEntity>("GetUserData", dbParameters);

　　E、事务

using (var dbprovider = DbService.DefaultProvider)
{
　　try
　　{
　　dbprovider.Begin();

　　dbprovider.GetReqository<UserScoreEntity>().Insert(new UserScoreEntity
　　{
　　Id = Guid.NewGuid().ToString(),
　　score = 666,
　　UserId = 4
　　});

　　dbprovider.GetReqository<UserRoleEntity>().Insert(new UserRoleEntity
　　{
　　Id = 8,
　　UserId = 4,
　　RoleId = 2,
　　IsActive = false
　　});

　　dbprovider.Commit();
　　}
　　catch (Exception)
　　{
　　dbprovider.Rollback();
　　}
}

　　F、执行Sql语句

var ds = DbService.DbExtension.ExcuteQuery("select * from dbo.CICUser");

foreach (DataRow row in ds.Tables[0].Rows)
{
　　Console.WriteLine(row[0]);
}