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前幾天有人想做一個多租戶的平臺,每個租戶一個庫,可以進行水平擴展,應用端根據登錄信息,切換到不同的租戶庫

計劃用ef core實現,他們說做不出來,需要動態創建dbContext,不好實現

然而這個使用CRL很輕松就能解決了

以下為演示數據庫,有兩個庫testdb和testdb2,查詢結果如下

詳解在.net core中完美解決多租戶分庫分表的問題

目標:

根據傳入登錄信息連不不同的庫,查詢返回結果,如登錄人為01,返回d1.default,登錄人為02 返回 d2.default

實際上這個需求就是分庫分表的實現,通過設置數據庫/表映射關系,根據傳入的定位數據進行匹配,找到正確的庫表配置,生成數據訪問對象

以core控制臺程序為例

									class Program

									  {

									    static IServiceProvider provider;

									    static Program()

									    {

									      var services = new ServiceCollection();

									      services.AddCRL<DBLocationCreator>();

									      services.AddScoped<Code.Sharding.MemberManage>();

									      provider = services.BuildServiceProvider();

									      provider.UseCRL();

									    }

									    static void Main(string[] args)

									    {

									    label1:

									      var instance = provider.GetService<Code.Sharding.MemberManage>();

									      var data = new Code.Sharding.MemberSharding();

									      data.Code = "01";

									      instance.SetLocation(data);

									      var find1 = instance.QueryItem(b => b.Id > 0)?.Name;

									      Console.WriteLine($"定位數據輸入{data.Code},查詢值為{find1}");

									      data.Code = "02";

									      instance.SetLocation(data);

									      var find2 = instance.QueryItem(b => b.Id > 0)?.Name;

									      Console.WriteLine($"定位數據輸入{data.Code},查詢值為{find2}");

									      Console.ReadLine();

									      goto label1;

									    }

									  }

上面代碼中,通過SetLocation方法傳入定位數據Code,通過QueryItem方法查詢出數據并打印出來

通過services.AddCRL<DBLocationCreator>()注入定位配置,DBLocationCreator繼承了接口IDBLocationCreator

這里完全符合core注入規范,可以通過配置或數據庫存儲動態讀取定位設置

									public class DBLocationCreator : IDBLocationCreator

									  {

									    ISettingConfigBuilder _settingConfigBuilder;

									    public DBLocationCreator(ISettingConfigBuilder settingConfigBuilder)

									    {

									      _settingConfigBuilder = settingConfigBuilder;

									    }

									    public void Init()

									    {

									      //自定義定位

									      _settingConfigBuilder.RegisterLocation<Code.Sharding.MemberSharding>((t, a) =>

									      {

									        var tableName = t.TableName;

									        var dbName = a.Code == "02" ? "testdb2" : "testdb";

									        var dataBase = $"Data Source=.;Initial Catalog={dbName};User ID=sa;Password=123";

									        //返回定位庫和表名

									        return new CRL.Sharding.Location(dataBase, tableName);

									      });

									      _settingConfigBuilder.RegisterDBAccessBuild(dbLocation =>

									      {

									        var connectionString = "Data Source=.;Initial Catalog=testdb;User ID=sa;Password=123";

									        if (dbLocation.ShardingLocation != null)

									        {

									          connectionString = dbLocation.ShardingLocation.DataBaseSource;

									        }

									        return new CRL.DBAccessBuild(DBType.MSSQL, connectionString);

									      });

									    }

									  }