分表

当某个业务表数据量规模比较大而影响查询性能时，可以采取分表的方式将数据拆分开，sharding-core 支持按照时间、取模等

配置分表

1. 添加包NetCorePal.Extensions.ShardingCore引用：

   dotnet add package NetCorePal.Extensions.ShardingCore
   

   或者 PackageReference

   <PackageReference Include="NetCorePal.Extensions.ShardingCore" />
   

2. 为你的 DbContext 类型添加 IShardingCore 接口

   public partial class ApplicationDbContext : AppDbContextBase, IShardingCore
   {
       //Your Code
   }  
   

3. 创建ApplicationDbContextCreator

   public class ApplicationDbContextCreator(IShardingProvider provider)
       : IDbContextCreator
   {
       public DbContext CreateDbContext(DbContext shellDbContext, ShardingDbContextOptions shardingDbContextOptions)
       {
           var outDbContext = (ApplicationDbContext)shellDbContext;
           var dbContext = new ApplicationDbContext(
               (DbContextOptions<ApplicationDbContext>)shardingDbContextOptions.DbContextOptions, outDbContext.Mediator);
           if (dbContext is IShardingTableDbContext shardingTableDbContext)
           {
               shardingTableDbContext.RouteTail = shardingDbContextOptions.RouteTail;
           }
   
           _ = dbContext.Model;
           return dbContext;
       }
   
       public DbContext GetShellDbContext(IShardingProvider shardingProvider)
       {
           return shardingProvider.GetRequiredService<ApplicationDbContext>();
       }
   }
   

4. 移除 AddDbContext 注册方式

   builder.Services.AddDbContext<ApplicationDbContext>(options =>
       {
           options.UseMySql(builder.Configuration.GetConnectionString("Mysql"),
               new MySqlServerVersion(new Version(8, 0, 34)),
               b => { b.MigrationsAssembly(typeof(Program).Assembly.FullName); });
       });
   

5. 为表添加分表配置：

   public class OrderVirtualTableRoute : AbstractSimpleShardingMonthKeyDateTimeVirtualTableRoute<Order>
   {
       public override DateTime GetBeginTime()
       {
           return DateTime.Now.AddMonths(-3);
       }
   
       public override void Configure(EntityMetadataTableBuilder<Order> builder)
       {
           builder.ShardingProperty(o => o.CreationTime);
       }
   
       public override bool AutoCreateTableByTime()
       {
           return true;
       }
   }
   

6. 使用 AddShardingDbContext 注册ApplicationDbContext:

   builder.Services.AddShardingDbContext<ApplicationDbContext>()
           .UseRouteConfig(op =>
           {
              op.AddShardingTableRoute<OrderVirtualTableRoute>(); //注册分表配置
           })
           .UseConfig(op =>
           {
               op.ThrowIfQueryRouteNotMatch = true;
               op.UseShardingQuery((conStr, builder) =>
               {
                   builder.UseMySql(conStr,
                       new MySqlServerVersion(new Version(8, 0, 34)));
               });
               op.UseShardingTransaction((con, builder) =>
               {
                   builder.UseMySql(con,
                       new MySqlServerVersion(new Version(8, 0, 34)));
               });
               op.AddDefaultDataSource("ds0", builder.Configuration.GetConnectionString("Mysql")); //配置写库
           })
           .ReplaceService<IDbContextCreator, ApplicationDbContextCreator>()
           .AddShardingCore();
   

高级

更多关于分表的配置和使用可以参考官方文档： https://xuejmnet.github.io/sharding-core-doc/sharding-table/init/