Choe.Orm框架下

Choe.Orm框架下的mysql技术
高效开发的NET.c#数据库访问框架（ORM）查询接口使用lambda表达式，使用对象的方法可以完成多表查询，分组查询，聚合查询，插入数据和批量操作。

public enum Gender

{

Man = 1,Woman

}

[Table(“Users”)]

public class User

{

[Column(IsPrimaryKey = true)][AutoIncrement]public int Id { get; set; }public string Name { get; set; }public Gender? Gender { get; set; }public int? Age { get; set; }public int? CityId { get; set; }public DateTime? OpTime { get; set; }

}

public class City

{

[Column(IsPrimaryKey = true)]public int Id { get; set; }public string Name { get; set; }public int ProvinceId { get; set; }

}

public class Province

{

[Column(IsPrimaryKey = true)]public int Id { get; set; }public string Name { get; set; }

}

建个 MySqlConnectionFactory 类，实现 IDbConnectionFactory 接口：

public class MySqlConnectionFactory : IDbConnectionFactory

{

string _connString = null;public MySqlConnectionFactory(string connString){this._connString = connString;}public IDbConnection CreateConnection(){MySqlConnection conn = new MySqlConnection(this._connString);return conn;}

}

创建一个 DbContext：

MySqlContext context = new MySqlContext(new MySqlConnectionFactory(DbHelper.ConnectionString));

再创建一个 IQuery：

IQuery q = context.Query();

查询数据

基本查询

IQuery q = context.Query();

q.Where(a => a.Id == 1).FirstOrDefault();

/*

• SELECT Users.Id AS Id,Users.Name AS Name,Users.Gender AS Gender,Users.Age AS Age,Users.CityId AS CityId,Users.OpTime AS OpTime FROM Users AS Users WHERE Users.Id = 1 LIMIT 0,1

  */

//可以选取指定的字段

q.Where(a => a.Id == 1).Select(a => new { a.Id, a.Name }).FirstOrDefault();

/*

• SELECT Users.Id AS Id,Users.Name AS Name FROM Users AS Users WHERE Users.Id = 1 LIMIT 0,1

  */

//分页

q.Where(a => a.Id > 0).OrderBy(a => a.Age).Skip(1).Take(999).ToList();

/*

• SELECT Users.Id AS Id,Users.Name AS Name,Users.Gender AS Gender,Users.Age AS Age,Users.CityId AS CityId,Users.OpTime AS OpTime FROM Users AS Users WHERE Users.Id > 0 ORDER BY Users.Age ASC LIMIT 1,999

  */

连接查询

IQuery users = context.Query();

IQuery cities = context.Query();

IQuery provinces = context.Query();

//建立连接

IJoiningQuery

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