.Net极限生产力之分表分库全自动化Migrations Code-First_实用技巧_

//请安装最新版本目前x.6.0.3+,第一个版本号6代表efcore的版本号 Install-Package ShardingCore -Version 6.6.0.3 Install-Package Pomelo.EntityFrameworkCore.MySql -Version 6.0.1 Install-Package Microsoft.EntityFrameworkCore.Tools -Version 6.0.6

public class TodoItem { public string Id { get; set; } public string Text { get; set; } }

public class MyDbContext:AbstractShardingDbContext,IShardingTableDbContext { public MyDbContext(DbContextOptions options) : base(options) { } public IRouteTail RouteTail { get; set; } protected override void OnModelCreating(ModelBuilder modelBuilder) { base.OnModelCreating(modelBuilder); modelBuilder.Entity(mb => { mb.HasKey(o => o.Id); mb.Property(o => o.Id).IsRequired().HasMaxLength(50).HasComment("id"); mb.Property(o => o.Text).IsRequired().HasMaxLength(256).HasComment("事情"); mb.ToTable(nameof(TodoItem)); }); } }

public class TodoItemDataSourceRoute:AbstractShardingOperatorVirtualDataSourceRoute { /// 
 /// id的hashcode取模余3分库 /// 
 ///  ///  ///  public override string ShardingKeyToDataSourceName(object shardingKey) { if (shardingKey == null) throw new InvalidOperationException("sharding key cant null"); var stringHashCode = ShardingCoreHelper.GetStringHashCode(shardingKey.ToString()); return $"ds{(Math.Abs(stringHashCode) % 3)}";//ds0,ds1,ds2 } private readonly List _dataSources = new List() { "ds0", "ds1", "ds2" }; public override List GetAllDataSourceNames() { return _dataSources; } public override bool AddDataSourceName(string dataSourceName) { throw new NotImplementedException(); } /// 
 /// id分库 /// 
 ///  public override void Configure(EntityMetadataDataSourceBuilder builder) { builder.ShardingProperty(o => o.Id); } public override Func GetRouteToFilter(string shardingKey, ShardingOperatorEnum shardingOperator) { var t = ShardingKeyToDataSourceName(shardingKey); switch (shardingOperator) { case ShardingOperatorEnum.Equal: return tail => tail == t; default: { return tail => true; } } } }

public class TodoItemTableRoute:AbstractSimpleShardingModKeyStringVirtualTableRoute { public TodoItemTableRoute() : base(2, 3) { } /// 
 /// 正常情况下不会用内容来做分片键因为作为分片键有个前提就是不会被修改 /// 
 ///  public override void Configure(EntityMetadataTableBuilder builder) { builder.ShardingProperty(o => o.Text); } }

public class ShardingMySqlMigrationsSqlGenerator:MySqlMigrationsSqlGenerator { private readonly IShardingRuntimeContext _shardingRuntimeContext; public ShardingMySqlMigrationsSqlGenerator(MigrationsSqlGeneratorDependencies dependencies, IRelationalAnnotationProvider annotationProvider, IMySqlOptions options,IShardingRuntimeContext shardingRuntimeContext) : base(dependencies, annotationProvider, options) { _shardingRuntimeContext = shardingRuntimeContext; } protected override void Generate( MigrationOperation operation, IModel model, MigrationCommandListBuilder builder) { var oldCmds = builder.GetCommandList().ToList(); base.Generate(operation, model, builder); var newCmds = builder.GetCommandList().ToList(); var addCmds = newCmds.Where(x => !oldCmds.Contains(x)).ToList(); MigrationHelper.Generate(_shardingRuntimeContext,operation, builder, Dependencies.SqlGenerationHelper, addCmds); } }

ILoggerFactory efLogger = LoggerFactory.Create(builder => { builder.AddFilter((category, level) => category == DbLoggerCategory.Database.Command.Name && level == LogLevel.Information).AddConsole(); }); var builder = WebApplication.CreateBuilder(args); builder.Services.AddControllers(); builder.Services.AddShardingDbContext() .UseRouteConfig(op => { op.AddShardingTableRoute(); op.AddShardingDataSourceRoute(); }) .UseConfig((sp,op) => { op.UseShardingQuery((con, b) => { b.UseMySql(con, new MySqlServerVersion(new Version())) .UseLoggerFactory(efLogger); }); op.UseShardingTransaction((con, b) => { b.UseMySql(con, new MySqlServerVersion(new Version())) .UseLoggerFactory(efLogger); }); op.AddDefaultDataSource("ds0", "server=127.0.0.1;port=3306;database=mydb0;userid=root;password=root;"); op.AddExtraDataSource(sp=>new Dictionary() { {"ds1", "server=127.0.0.1;port=3306;database=mydb1;userid=root;password=root;"}, {"ds2", "server=127.0.0.1;port=3306;database=mydb2;userid=root;password=root;"} }); op.UseShardingMigrationConfigure(b => { b.ReplaceService(); }); }).AddShardingCore(); var app = builder.Build(); // Configure the HTTP request pipeline. //如果有按时间分片的需要加定时任务否则可以不加 app.Services.UseAutoShardingCreate(); using (var scope = app.Services.CreateScope()) { var defaultShardingDbContext = scope.ServiceProvider.GetRequiredService(); if (defaultShardingDbContext.Database.GetPendingMigrations().Any()) { defaultShardingDbContext.Database.Migrate(); } } //如果需要在启动后扫描是否有表却扫了可以添加这个 //app.Services.UseAutoTryCompensateTable(); //...... app.Run();

Add-Migration Init

public class TodoItem { public string Id { get; set; } public string Text { get; set; } public string Name { get; set; } } public class TodoTest { public string Id { get; set; } public string Test { get; set; } } //docontext protected override void OnModelCreating(ModelBuilder modelBuilder) { base.OnModelCreating(modelBuilder); modelBuilder.Entity(mb => { mb.HasKey(o
                
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