控制事务

可以使用 DbContext.Database API 开始、提交和回滚事务。 以下示例显示了在单个事务中执行的两个 SaveChanges 操作以及一个 LINQ 查询：

using var context = new BloggingContext();
using var transaction = context.Database.BeginTransaction();try
{context.Blogs.Add(new Blog { Url = "http://blogs.msdn.com/dotnet" });context.SaveChanges();context.Blogs.Add(new Blog { Url = "http://blogs.msdn.com/visualstudio" });context.SaveChanges();var blogs = context.Blogs.OrderBy(b => b.Url).ToList();// Commit transaction if all commands succeed, transaction will auto-rollback// when disposed if either commands failstransaction.Commit();
}
catch (Exception)
{// TODO: Handle failure
}

虽然所有关系数据库提供程序都支持事务，但在调用事务 API 时，可能会引发其他提供程序类型或不执行任何操作。

使用 System.Transactions

如果需要跨较大作用域进行协调，则可以使用环境事务。

using (var scope = new TransactionScope(TransactionScopeOption.Required,new TransactionOptions { IsolationLevel = IsolationLevel.ReadCommitted }))
{using var connection = new SqlConnection(connectionString);connection.Open();try{// Run raw ADO.NET command in the transactionvar command = connection.CreateCommand();command.CommandText = "DELETE FROM dbo.Blogs";command.ExecuteNonQuery();// Run an EF Core command in the transactionvar options = new DbContextOptionsBuilder<BloggingContext>().UseSqlServer(connection).Options;using (var context = new BloggingContext(options)){context.Blogs.Add(new Blog { Url = "http://blogs.msdn.com/dotnet" });context.SaveChanges();}// Commit transaction if all commands succeed, transaction will auto-rollback// when disposed if either commands failsscope.Complete();}catch (Exception){// TODO: Handle failure}
}

还可以在显式事务中登记。

using (var transaction = new CommittableTransaction(new TransactionOptions { IsolationLevel = IsolationLevel.ReadCommitted }))
{var connection = new SqlConnection(connectionString);try{var options = new DbContextOptionsBuilder<BloggingContext>().UseSqlServer(connection).Options;using (var context = new BloggingContext(options)){context.Database.OpenConnection();context.Database.EnlistTransaction(transaction);// Run raw ADO.NET command in the transactionvar command = connection.CreateCommand();command.CommandText = "DELETE FROM dbo.Blogs";command.ExecuteNonQuery();// Run an EF Core command in the transactioncontext.Blogs.Add(new Blog { Url = "http://blogs.msdn.com/dotnet" });context.SaveChanges();context.Database.CloseConnection();}// Commit transaction if all commands succeed, transaction will auto-rollback// when disposed if either commands failstransaction.Commit();}catch (Exception){// TODO: Handle failure}
}

System.Transactions 的限制

1. EF Core 依赖数据库提供程序以实现对 System.Transactions 的支持。 如果提供程序未实现对 System.Transactions 的支持，则可能会完全忽略对这些 API 的调用。 SqlClient 支持它。

2. 自 .NET Core 2.1 起，System.Transactions 实现不包括对分布式事务的支持，因此不能使用 TransactionScope 或 CommittableTransaction 来跨多个资源管理器协调事务。