[开源].NET高性能框架Chloe.ORM-完美支持SQLite

扯淡

这是一款轻量、高效的.NET C#数据库访问框架(ORM)。查询接口借鉴 Linq(但不支持 Linq)。借助 lambda 表达式，可以完全用面向对象的方式就能轻松执行多表连接查询、分组查询、聚合查询、插入数据、批量删除和更新等操作。

多数据库支持，已然成为 ORM 的标配。继开发了 Chloe 的 .NET Core 版本后，Chloe 继续她的多数据库支持之路。上周花了些时间学习了 SQLite，现在已经支持 SQLite 数据库。

导航

• Chloe.ORM
  • 事前准备
  • 查询数据
    • 基本查询
    • 连接查询
    • 聚合查询
    • 分组查询
  • 插入数据
  • 更新数据
  • 删除数据
  • 支持函数
• 坎坎坷坷
• 结语

Chloe.ORM

事前准备

实体：

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; }
}

因为框架不依赖具体的数据库驱动，所以得先建个 SQLiteConnectionFactory 类，实现 IDbConnectionFactory 接口：

public class SQLiteConnectionFactory : IDbConnectionFactory
{
    string _connString = null;
    public SQLiteConnectionFactory(string connString)
    {
        this._connString = connString;
    }
    public IDbConnection CreateConnection()
    {
        SQLiteConnection conn = new SQLiteConnection(this._connString);
        return conn;
    }
}

然后通过构造函数注入的方式创建一个 DbContext：

SQLiteContext context = new SQLiteContext(new SQLiteConnectionFactory(DbHelper.ConnectionString));

再创建一个 IQuery<T>：

IQuery<User> q = context.Query<User>();

查询数据

基本查询

IQuery<User> q = context.Query<User>();

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 1 OFFSET 0
 */

//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 1 OFFSET 0
 */

//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 999 OFFSET 1
 */

连接查询

IQuery<User> users = context.Query<User>();
IQuery<City> cities = context.Query<City>();
IQuery<Province> provinces = context.Query<Province>();

//建立连接
IJoiningQuery<User, City> user_city = users.InnerJoin(cities, (user, city) => user.CityId == city.Id);
IJoiningQuery<User, City, Province> user_city_province = user_city.InnerJoin(provinces, (user, city, province) => city.ProvinceId == province.Id);

//查出一个用户及其隶属的城市和省份的所有信息
user_city_province.Select((user, city, province) => new { User = user, City = city, Province = province }).Where(a => a.User.Id == 1).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],[City].[Id] AS [Id0],[City].[Name] AS [Name0],[City].[ProvinceId] AS [ProvinceId],[Province].[Id] AS [Id1],[Province].[Name] AS [Name1] FROM [Users] AS [Users] INNER JOIN [City] AS [City] ON [Users].[CityId] = [City].[Id] INNER JOIN [Province] AS [Province] ON [City].[ProvinceId] = [Province].[Id] WHERE [Users].[Id] = 1
 */

//也可以只获取指定的字段信息：UserId,UserName,CityName,ProvinceName
user_city_province.Select((user, city, province) => new { UserId = user.Id, UserName = user.Name, CityName = city.Name, ProvinceName = province.Name }).Where(a => a.UserId == 1).ToList();
/*
 * SELECT [Users].[Id] AS [UserId],[Users].[Name] AS [UserName],[City].[Name] AS [CityName],[Province].[Name] AS [ProvinceName] FROM [Users] AS [Users] INNER JOIN [City] AS [City] ON [Users].[CityId] = [City].[Id] INNER JOIN [Province] AS [Province] ON [City].[ProvinceId] = [Province].[Id] WHERE [Users].[Id] = 1
 */

聚合查询

IQuery<User> q = context.Query<User>();

q.Select(a => AggregateFunctions.Count()).First();
/*
 * SELECT COUNT(1) AS [C] FROM [Users] AS [Users] LIMIT 1 OFFSET 0
 */

q.Select(a => new { Count = AggregateFunctions.Count(), LongCount = AggregateFunctions.LongCount(), Sum = AggregateFunctions.Sum(a.Age), Max = AggregateFunctions.Max(a.Age), Min = AggregateFunctions.Min(a.Age), Average = AggregateFunctions.Average(a.Age) }).First();
/*
 * SELECT COUNT(1) AS [Count],COUNT(1) AS [LongCount],CAST(SUM([Users].[Age]) AS INTEGER) AS [Sum],CAST(MAX([Users].[Age]) AS INTEGER) AS [Max],CAST(MIN([Users].[Age]) AS INTEGER) AS [Min],CAST(AVG([Users].[Age]) AS REAL) AS [Average] FROM [Users] AS [Users] LIMIT 1 OFFSET 0
 */

var count = q.Count();
/*
 * SELECT COUNT(1) AS [C] FROM [Users] AS [Users]
 */

var longCount = q.LongCount();
/*
 * SELECT COUNT(1) AS [C] FROM [Users] AS [Users]
 */

var sum = q.Sum(a => a.Age);
/*
 * SELECT CAST(SUM([Users].[Age]) AS INTEGER) AS [C] FROM [Users] AS [Users]
 */

var max = q.Max(a => a.Age);
/*
 * SELECT CAST(MAX([Users].[Age]) AS INTEGER) AS [C] FROM [Users] AS [Users]
 */

var min = q.Min(a => a.Age);
/*
 * SELECT CAST(MIN([Users].[Age]) AS INTEGER) AS [C] FROM [Users] AS [Users]
 */

var avg = q.Average(a => a.Age);
/*
 * SELECT CAST(AVG([Users].[Age]) AS REAL) AS [C] FROM [Users] AS [Users]
 */

分组查询

IQuery<User> q = context.Query<User>();

IGroupingQuery<User> g = q.Where(a => a.Id > 0).GroupBy(a => a.Age);

g = g.Having(a => a.Age > 1 && AggregateFunctions.Count() > 0);

g.Select(a => new { a.Age, Count = AggregateFunctions.Count(), Sum = AggregateFunctions.Sum(a.Age), Max = AggregateFunctions.Max(a.Age), Min = AggregateFunctions.Min(a.Age), Avg = AggregateFunctions.Average(a.Age) }).ToList();
/*
 * SELECT [Users].[Age] AS [Age],COUNT(1) AS [Count],CAST(SUM([Users].[Age]) AS INTEGER) AS [Sum],CAST(MAX([Users].[Age]) AS INTEGER) AS [Max],CAST(MIN([Users].[Age]) AS INTEGER) AS [Min],CAST(AVG([Users].[Age]) AS REAL) AS [Avg] FROM [Users] AS [Users] WHERE [Users].[Id] > 0 GROUP BY [Users].[Age] HAVING ([Users].[Age] > 1 AND COUNT(1) > 0)
 */

插入数据

方式1

以 lambda 表达式树的方式插入：

//返回主键 Id
int id = (int)context.Insert<User>(() => new User() { Name = "lu", Age = 18, Gender = Gender.Man, CityId = 1, OpTime = DateTime.Now });
/*
 * INSERT INTO [Users]([Name],[Age],[Gender],[CityId],[OpTime]) VALUES('lu',18,1,1,DATETIME('NOW','LOCALTIME'));SELECT LAST_INSERT_ROWID()
 */

方式2

以实体的方式插入：

User user = new User();
user.Name = "lu";
user.Age = 18;
user.Gender = Gender.Man;
user.CityId = 1;
user.OpTime = DateTime.Now;

//会自动将自增 Id 设置到 user 的 Id 属性上
user = context.Insert(user);
/*
 * String @P_0 = 'lu';
   Gender @P_1 = Man;
   Int32 @P_2 = 18;
   Int32 @P_3 = 1;
   DateTime @P_4 = '2016/8/6 22:03:42';
   INSERT INTO [Users]([Name],[Gender],[Age],[CityId],[OpTime]) VALUES(@P_0,@P_1,@P_2,@P_3,@P_4);SELECT LAST_INSERT_ROWID()
 */

更新数据

方式1

以 lambda 表达式树的方式更新：

context.Update<User>(a => new User() { Name = a.Name, Age = a.Age + 100, Gender = Gender.Man, OpTime = DateTime.Now }, a => a.Id == 1);
/*
 * UPDATE [Users] SET [Name]=[Users].[Name],[Age]=([Users].[Age] + 100),[Gender]=1,[OpTime]=DATETIME('NOW','LOCALTIME') WHERE [Users].[Id] = 1
 */

//批量更新
//给所有女性朋友年轻 10 岁
context.Update<User>(a => new User() { Age = a.Age - 10, OpTime = DateTime.Now }, a => a.Gender == Gender.Woman);
/*
 * UPDATE [Users] SET [Age]=([Users].[Age] - 10),[OpTime]=DATETIME('NOW','LOCALTIME') WHERE [Users].[Gender] = 2
 */

方式2

以实体的方式更新：

User user = new User();
user.Id = 1;
user.Name = "lu";
user.Age = 28;
user.Gender = Gender.Man;
user.OpTime = DateTime.Now;

context.Update(user); //会更新所有映射的字段
/*
 * String @P_0 = 'lu';
   Gender @P_1 = Man;
   Int32 @P_2 = 28;
   Nullable<Int32> @P_3 = NULL;
   DateTime @P_4 = '2016/8/6 22:05:02';
   Int32 @P_5 = 1;
   UPDATE [Users] SET [Name]=@P_0,[Gender]=@P_1,[Age]=@P_2,[CityId]=@P_3,[OpTime]=@P_4 WHERE [Users].[Id] = @P_5
 */

/*
 * 支持只更新属性值已变的属性
 */

context.TrackEntity(user);//在上下文中跟踪实体
user.Name = user.Name + "";
context.Update(user);//这时只会更新被修改的字段
/*
 * String @P_0 = 'lu1';
   Int32 @P_1 = 1;
   UPDATE [Users] SET [Name]=@P_0 WHERE [Users].[Id] = @P_1
 */

删除数据

方式1

以 lambda 表达式树的方式删除：

context.Delete<User>(a => a.Id == 1);
/*
 * DELETE FROM [Users] WHERE [Users].[Id] = 1
 */

//批量删除
//删除所有不男不女的用户
context.Delete<User>(a => a.Gender == null);
/*
 * DELETE FROM [Users] WHERE [Users].[Gender] IS NULL
 */

方式2

以实体的方式删除：

User user = new User();
user.Id = 1;
context.Delete(user);
/*
 * Int32 @P_0 = 1;
   DELETE FROM [Users] WHERE [Users].[Id] = @P_0
 */

支持函数

IQuery<User> q = context.Query<User>();

var space = new char[] { ' ' };

DateTime startTime = DateTime.Now;
DateTime endTime = DateTime.Now.AddDays(1);

var ret = q.Select(a => new
{
    Id = a.Id,

    String_Length = (int?)a.Name.Length,//LENGTH([Users].[Name])
    Substring = a.Name.Substring(0),//SUBSTR([Users].[Name],0 + 1)
    Substring1 = a.Name.Substring(1),//SUBSTR([Users].[Name],1 + 1)
    Substring1_2 = a.Name.Substring(1, 2),//SUBSTR([Users].[Name],1 + 1,2)
    ToLower = a.Name.ToLower(),//LOWER([Users].[Name])
    ToUpper = a.Name.ToUpper(),//UPPER([Users].[Name])
    IsNullOrEmpty = string.IsNullOrEmpty(a.Name),//CASE WHEN ([Users].[Name] IS NULL OR [Users].[Name] = '') THEN 1 ELSE 0 END = 1
    Contains = (bool?)a.Name.Contains("s"),//[Users].[Name] LIKE '%' || 's' || '%'
    StartsWith = (bool?)a.Name.StartsWith("s"),//[Users].[Name] LIKE 's' || '%'
    EndsWith = (bool?)a.Name.EndsWith("s"),//[Users].[Name] LIKE '%' || 's'
    Trim = a.Name.Trim(),//TRIM([Users].[Name])
    TrimStart = a.Name.TrimStart(space),//LTRIM([Users].[Name])
    TrimEnd = a.Name.TrimEnd(space),//RTRIM([Users].[Name])

    DiffYears = DbFunctions.DiffYears(startTime, endTime),//(CAST(STRFTIME('%Y',@P_0) AS INTEGER) - CAST(STRFTIME('%Y',@P_1) AS INTEGER))
    DiffMonths = DbFunctions.DiffMonths(startTime, endTime),//((CAST(STRFTIME('%Y',@P_0) AS INTEGER) - CAST(STRFTIME('%Y',@P_1) AS INTEGER)) * 12 + (CAST(STRFTIME('%m',@P_0) AS INTEGER) - CAST(STRFTIME('%m',@P_1) AS INTEGER)))
    DiffDays = DbFunctions.DiffDays(startTime, endTime),//CAST((JULIANDAY(@P_0) - JULIANDAY(@P_1)) AS INTEGER)
    DiffHours = DbFunctions.DiffHours(startTime, endTime),//CAST((JULIANDAY(@P_0) - JULIANDAY(@P_1)) * 24 AS INTEGER)
    DiffMinutes = DbFunctions.DiffMinutes(startTime, endTime),//CAST((JULIANDAY(@P_0) - JULIANDAY(@P_1)) * 1440 AS INTEGER)
    DiffSeconds = DbFunctions.DiffSeconds(startTime, endTime),//CAST((JULIANDAY(@P_0) - JULIANDAY(@P_1)) * 86400 AS INTEGER)
    //DiffMilliseconds = DbFunctions.DiffMilliseconds(startTime, endTime),//不支持 Millisecond
    //DiffMicroseconds = DbFunctions.DiffMicroseconds(startTime, endTime),//不支持 Microseconds

    AddYears = startTime.AddYears(1),//DATETIME(@P_0,'+' || 1 || ' years')
    AddMonths = startTime.AddMonths(1),//DATETIME(@P_0,'+' || 1 || ' months')
    AddDays = startTime.AddDays(1),//DATETIME(@P_0,'+' || 1 || ' days')
    AddHours = startTime.AddHours(1),//DATETIME(@P_0,'+' || 1 || ' hours')
    AddMinutes = startTime.AddMinutes(2),//DATETIME(@P_0,'+' || 2 || ' minutes')
    AddSeconds = startTime.AddSeconds(120),//DATETIME(@P_0,'+' || 120 || ' seconds')
    //AddMilliseconds = startTime.AddMilliseconds(2000),//不支持

    Now = DateTime.Now,//DATETIME('NOW','LOCALTIME')
    UtcNow = DateTime.UtcNow,//DATETIME()This method can not pass parameters
    Today = DateTime.Today,//DATE('NOW','LOCALTIME')
    Date = DateTime.Now.Date,//DATE('NOW','LOCALTIME')
    Year = DateTime.Now.Year,//CAST(STRFTIME('%Y',DATETIME('NOW','LOCALTIME')) AS INTEGER)
    Month = DateTime.Now.Month,//CAST(STRFTIME('%m',DATETIME('NOW','LOCALTIME')) AS INTEGER)
    Day = DateTime.Now.Day,//CAST(STRFTIME('%d',DATETIME('NOW','LOCALTIME')) AS INTEGER)
    Hour = DateTime.Now.Hour,//CAST(STRFTIME('%H',DATETIME('NOW','LOCALTIME')) AS INTEGER)
    Minute = DateTime.Now.Minute,//CAST(STRFTIME('%M',DATETIME('NOW','LOCALTIME')) AS INTEGER)
    Second = DateTime.Now.Second,//CAST(STRFTIME('%S',DATETIME('NOW','LOCALTIME')) AS INTEGER)
    Millisecond = DateTime.Now.Millisecond,//@P_2 直接计算 DateTime.Now.Millisecond 的值
    DayOfWeek = DateTime.Now.DayOfWeek,//CAST(STRFTIME('%w',DATETIME('NOW','LOCALTIME')) AS INTEGER)

    Byte_Parse = "),//CAST('1' AS INTEGER)
    Int_Parse = "),//CAST('1' AS INTEGER)
    Int16_Parse = Int16.Parse(""),//CAST('11' AS INTEGER)
    Long_Parse = "),//CAST('2' AS INTEGER)
    Double_Parse = double.Parse("3.1"),//CAST('3.1' AS REAL)
    Float_Parse = float.Parse("4.1"),//CAST('4.1' AS REAL)
    //Decimal_Parse = decimal.Parse("5"),//不支持
    //Guid_Parse = Guid.Parse("D544BC4C-739E-4CD3-A3D3-7BF803FCE179"),//不支持 'D544BC4C-739E-4CD3-A3D3-7BF803FCE179'

    Bool_Parse = "),//CAST('1' AS INTEGER)
    DateTime_Parse = DateTime.Parse("2014-01-01"),//DATETIME('2014-01-01')
}).ToList();

坎坎坷坷

SQLite 也是一个关系型数据库，之前开发 MySql Provider 的时候已经积累了些经验，因此，这回开发 SQLite 的 Provider 几乎不费吹灰之力。不过 SQLite 稍微比 MySql “恶心”那么一点：

1. MySql 不支持 Full Join，SQLite 不支持 Full Join 的同时连 Right Join 也不支持，这是为啥呢？不过不要紧，既然不支持 Right Join，那开发的时候将本是放在 Right 一边的表用 Left Join 去连接其他表就好。支持 Right Join 应该不是难事，只是很奇怪 SQLite 为啥不支持呢！
2. 支持的函数相对比 SqlServer 和 MySql 要少些，比如，获取两个日期的年差、月差、时差等函数，因为 SQLite 只支持日差函数，因此为了支持 Chloe 的 DbFunctions.DiffYears、DbFunctions.DiffMonths、DbFunctions.DiffHours 等方法，得将其翻译成既长又奇葩的语句- -。

当然，还有其它的不同，但都有变通的方式支持，就不一一列举了。

结语

从最初只支持 SqlServer 到现在支持3种数据库，瞬间感觉 Chloe “高大上”了许多。多数据库支持这路还很长，对于其他数据库的支持，只是时间问题。接下来的发展目标是...待定- -。在开源的一个多月里，要支持这支持那，每周得去学习，同时要不断的维护代码(咱得对得起关注 Chloe 的同学- -)，真心有点儿小困，头发又少了很多555，接下来要好好休息放松一下先了。

文中代码都同步在 GitHub，地址：https://github.com/shuxinqin/Chloe/blob/master/src/DotNet/ChloeDemo/SQLiteDemo.cs。Demo 项目中已经包含 SQLite 驱动和数据文件，下载即可运行。

Chloe.ORM 完全开源，遵循 Apache2.0 协议，托管于 GitHub，地址：https://github.com/shuxinqin/Chloe。

相关介绍：http://www.cnblogs.com/so9527/p/5636216.html
性能测试：http://www.cnblogs.com/so9527/p/5674498.html