Fast ORM 读写分离功能使用

Fast Framework

作者 Mr-zhong

代码改变世界....

一、前言

Fast Framework 基于NET6.0 封装的轻量级 ORM 框架 支持多种数据库 SqlServer Oracle MySql PostgreSql Sqlite

优点： 体积小、原生支持微软特性、流畅API、使用简单、性能高、模型数据绑定采用 Expression、强大的表达式解析、支持多种子查询可实现较为复杂查询、源代码可读性强、支持AOT 编译。

缺点：目前仅支持Db Frist

开源地址：https://github.com/China-Mr-zhong/Fast.Framework （唯一）

ps：权重随机算法、支持故障转移、故障回调（可做日志记录或通知）

一、appsettings.json 配置

{
    "DbOptions": [
        {
            "DbId": "db_01",
            "DbType": "MySQL",
            "IsDefault": true,
            "ConnectionStrings": "server=localhost;database=Test;user=root;pwd=123456789;port=3306;min pool size=0;max pool size=100;connect timeout=120;AllowLoadLocalInfile=true;",
            "UseMasterSlaveSeparation": true, //使用主从分离 注意所有事务将强制走主库
            "SlaveItems": [
                {
                    "DbId": "A",
                    "Weight": 60,
                    "ConnectionStrings": "server=localhost;database=Test1;user=root;pwd=123456789;port=3306;min pool size=0;max pool size=100;connect timeout=120;AllowLoadLocalInfile=true;",
                    "Description": "A数据库"
                },
                {
                    "DbId": "B",
                    "Weight": 40,
                    "ConnectionStrings": "server=localhost;database=Test2;user=root;pwd=123456789;port=3306;min pool size=0;max pool size=100;connect timeout=120;AllowLoadLocalInfile=true;",
                    "Description": "B数据库"
                }
            ],
            "Description": "主库连接配置"
        }
    ]
}

二、 Program （入口配置）

            builder.Services.Configure<List<DbOptions>>(builder.Configuration.GetSection("DbOptions"));//注册Options接口
            builder.Services.AddFastDbContext();//添加上下文

四、使用示例

                db.Aop.SlaveDbFault = (options, ex) =>
                {
                    //故障回调
                    Console.WriteLine($"从库ID:{options.DbId} 发生故障!!! 异常信息:{ex.Message}");
                };

                var data = db.Query<Product>().First();

                Console.WriteLine(Json.Serialize(data));
                Console.WriteLine();
                Console.WriteLine($"从库索引:{db.Ado.CurrentSlaveDbIndex} 从库ID:{db.Ado.SlaveDbOptions.DbId}");

其它很棒的功能（原创基于作用域概念设计的子查询）

• Join子查询

  • 示例代码

                    var subQuery1 = db.Query<Product>().Select(s => new
                    {
                        s.ProductId,
                        s.CategoryId,
                        s.ProductCode,
                        s.ProductName,
                        s.DeleteMark
                    });
                    var data = db.Query<Category>().InnerJoin(subQuery1, (a, b) => a.CategoryId == b.CategoryId).ToList();
    

  • 执行后Sql

    SELECT p1.`CategoryId`,p1.`CategoryName`,p2.`ProductId`,p2.`ProductCode`,p2.`ProductName`,p2.`DeleteMark` FROM `Category` `p1`
    INNER JOIN ( SELECT `ProductId` AS `ProductId`,`CategoryId` AS `CategoryId`,`ProductCode` AS `ProductCode`,`ProductName` AS `ProductName`,`DeleteMark` AS `DeleteMark` FROM `Product` ) `p2` ON ( `p1`.`CategoryId` = `p2`.`CategoryId` )
    

• From子查询

  • 示例代码

                    var subQuery2 = db.Query<Product>().Select(s=>new
                    {
                        s.ProductId,
                        s.CategoryId,
                        s.ProductCode,
                        s.ProductName,
                        s.DeleteMark
                    });
                    var data = db.Query(subQuery2).ToList();
    

  • 执行后Sql

    SELECT * FROM ( SELECT `ProductId` AS `ProductId`,`CategoryId` AS `CategoryId`,`ProductCode` AS `ProductCode`,`ProductName` AS `ProductName`,`DeleteMark` AS `DeleteMark` FROM `Product` ) x
    

• Select子查询

  • 示例代码

                    var data = db.Query<Product>().Select(s => new
                    {
                        CategoryName = db.Query<Category>().Where(w => w.CategoryId == 1).Select(s => s.CategoryName).First()
                    }).First();
    

  • 执行后Sql

    SELECT ( SELECT `p2`.`CategoryName` FROM `Category` `p2`
    WHERE ( `p2`.`CategoryId` = 1 ) Limit 1 ) AS `CategoryName` FROM `Product` `p1` Limit 1
    

• Select嵌套查询

  • 示例代码

                    var data1 = db.Query<Product>().Select(s => new
                    {
                        NestedQuery = db.Query<Category>().Where(w => w.CategoryId == s.CategoryId).ToList()
                    }).First();
    
                    var data2 = db.Query<Product>().Where(w => w.ProductId == 1).Select(s => new
                    {
                        NestedQuery = db.Query<Category>().Where(w => w.CategoryId == s.CategoryId).ToList()
                    }).First();
    

  • 执行后Sql

    //内部机制主查询有结果才执行嵌套查询，懒加载实现
    
    SELECT 0 AS `fast_args_index_0` FROM `Product` `p1` Limit 1
    
    --------------------------------------------------------------------------
    
    SELECT p2.`CategoryId`,p2.`CategoryName`,p1.`ProductId`,p1.`ProductCode`,p1.`ProductName`,p1.`DeleteMark`,p1.`CreateTime`,p1.`ModifyTime`,p1.`Custom1`,p1.`Custom2`,p1.`Custom3`,p1.`Custom4`,p1.`Custom5`,p1.`Custom6`,p1.`Custom7`,p1.`Custom8`,p1.`Custom9`,p1.`Custom10`,p1.`Custom11`,p1.`Custom12` FROM `Category` `p2`
    RIGHT JOIN `Product` `p1` ON ( `p2`.`CategoryId` = `p1`.`CategoryId` )
    
    SELECT 0 AS `fast_args_index_0` FROM `Product` `p1`
    WHERE ( `p1`.`ProductId` = 1 ) Limit 1
    

• Where子查询

  • 示例代码

                    var data = db.Query<Category>().Where(w => w.CategoryId == 1 && db.Query<Product>().Where(w => w.CategoryId == 1).Select(s => 1).Any()).First();//Any支持取反
    

  • 执行后Sql

    SELECT p1.`CategoryId`,p1.`CategoryName` FROM `Category` `p1`
    WHERE ( ( `p1`.`CategoryId` = 1 ) AND EXISTS ( SELECT 1 FROM `Product` `p2`
    WHERE ( `p2`.`CategoryId` = 1 ) ) ) Limit 1
    

更多示例 https://www.cnblogs.com/China-Mr-zhong/p/17852177.html