在做項(xiàng)目時(shí)，需要將某一些功能的實(shí)體建立在另一個(gè)數(shù)據(jù)庫中，連接不同的數(shù)據(jù)庫用以存儲(chǔ)記錄。通過查找資料，實(shí)現(xiàn)EF Core上下文。
下面是實(shí)現(xiàn)上下文后的解決方案的目錄：

1.UpAndDownDbContext

2.UpAndDownDbContextConfigurer

3.UpAndDownDbContextFactory

以上三個(gè)文件為第二個(gè)數(shù)據(jù)庫的相關(guān)遷移和配置

4.新增MyConnectionStringResolver，根據(jù)不同的類型查找不同的數(shù)據(jù)庫連接串

5.在MyTestProjectEntityFrameworkModule文件中新增部分代碼，將MyConnectionStringResolver注入到Module中

namespace MyTestProject.EntityFrameworkCore
{
    [DependsOn(
        typeof(MyTestProjectCoreModule), 
        typeof(AbpZeroCoreEntityFrameworkCoreModule))]
    public class MyTestProjectEntityFrameworkModule : AbpModule
    {
        /* Used it tests to skip dbcontext registration, in order to use in-memory database of EF Core */
        public bool SkipDbContextRegistration { get; set; }

        public bool SkipDbSeed { get; set; }

        public override void PreInitialize()
        {
            #region 新增將計(jì)注入
            Configuration.ReplaceService(typeof(IConnectionStringResolver), () =>
            {
                IocManager.IocContainer.Register(
                    Component.For<IConnectionStringResolver>()
                        .ImplementedBy<MyConnectionStringResolver>()
                        .LifestyleTransient()
                );
            });
            #endregion

            if (!SkipDbContextRegistration)
            {
                Configuration.Modules.AbpEfCore().AddDbContext<MyTestProjectDbContext>(options =>
                {
                    if (options.ExistingConnection != null)
                    {
                        MyTestProjectDbContextConfigurer.Configure(options.DbContextOptions, options.ExistingConnection);
                    }
                    else
                    {
                        MyTestProjectDbContextConfigurer.Configure(options.DbContextOptions, options.ConnectionString);
                    }
                });
            }
            #region 注入
            // Configure workflow DbContext
            Configuration.Modules.AbpEfCore().AddDbContext<UpAndDownDbContext>(options =>
            {
                if (options.ExistingConnection != null)
                {
                    UpAndDownDbContextConfigurer.Configure(options.DbContextOptions, options.ExistingConnection);
                }
                else
                {
                    UpAndDownDbContextConfigurer.Configure(options.DbContextOptions, options.ConnectionString);
                }
            });
            #endregion

            ////Dapper
            //DapperExtensions.DapperExtensions.SqlDialect = new DapperExtensions.Sql.MySqlDialect();
        }

        public override void Initialize()
        {
            IocManager.RegisterAssemblyByConvention(typeof(MyTestProjectEntityFrameworkModule).GetAssembly());
        }

        //public override void PostInitialize()
        //{
        //    if (!SkipDbSeed)
        //    {
        //        SeedHelper.SeedHostDb(IocManager);
        //    }
        //}
    }
}

6.在appsettings.json設(shè)置另一個(gè)數(shù)據(jù)庫的連接串

7.在MyTestProjectConsts和SCMConsts中分別建立常量

以上就是實(shí)現(xiàn)數(shù)據(jù)庫上下文的所有的相關(guān)配置過程。

最后測試一波

執(zhí)行數(shù)據(jù)庫遷移 ,由于配置了上下文所以在遷移時(shí)要指定DbContext：Add-Migration (遷移名稱) -c UpAndDownDbContext(或MyTestProjectDbContext)。

若是不指定DbContext則會(huì)出現(xiàn)錯(cuò)誤：More than one DbContext was found. Specify which one to use. Use the '-Context' parameter for PowerShell commands and the '--context' parameter for dotnet commands.

整個(gè)的配置就完成了。