Entity Framework 和 MySQL 的 MassTransit saga 持久性
MassTransit saga persistance with Entity Framework and MySQL
我正在使用 MassTransit（使用 RabbitMQ）和 Automatonymous 开发一个 saga。我使用 EntityFramework 作为我的商店引擎和 MySQL 作为我的数据库。每次我尝试 运行 传奇并将其状态存储在数据库中时，EF 和 MySQL 的组合都会引发异常。使用 this 示例应用程序并使用到 MySQL 数据库的连接字符串可以重现该问题。抛出的确切异常是：
System.Data.SqlClient.SqlException (0x80131904): A network-related or
instance-specific error occurred while establishing a connection to
SQL Server. The server was not found or was not accessible. Ve rify
that the instance name is correct and that SQL Server is configured to
allow remote connections. (provider: Named Pipes Provider, error: 40 -
Could not open a connection to SQL Server) ---> Syste
m.ComponentModel.Win32Exception (0x80004005): The system cannot find
the file specified at
System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity
identity, SqlConnectionString connectionOptions, SqlCredential
credential, Object providerInfo, String newPassword, SecureString
newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString
userConnectionOptions, SessionData reconnectSessionData,
DbConnectionPool pool, String accessToken, Boolean applyTra
nsientFaultHandling) at
System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions
options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo,
DbConnectionPool pool, DbConnection owningConn ection,
DbConnectionOptions userOptions) at
System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool
pool, DbConnection owningObject, DbConnectionOptions options,
DbConnectionPoolKey poolKey, DbConnectionOption s userOptions) at
System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection
owningObject, DbConnectionOptions userOptions, DbConnectionInternal
oldConnection) at
System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection
owningObject, DbConnectionOptions userOptions, DbConnectionInternal
oldConnection) at
System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection
owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean
allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptio ns
userOptions, DbConnectionInternal& connection) at
System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection
owningObject, TaskCompletionSource1 retry, DbConnectionOptions
userOptions, DbConnectionInternal& connection) at
System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection
owningConnection, TaskCompletionSource1 retry, DbConnectionOptions
userOptions, DbConnectionInternal oldConnection, Db
ConnectionInternal& connection) at
System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection
outerConnection, DbConnectionFactory connectionFactory,
TaskCompletionSource1 retry, DbConnectionOptions use rOptions) at
System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection
outerConnection, DbConnectionFactory connectionFactory,
TaskCompletionSource1 retry, DbConnectionOptions userOptions) at
System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource1
retry) at
System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource1
retry) at System.Data.SqlClient.SqlConnection.Open() at
System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.b__36(DbConnection
t, DbConnectionInterceptionContext c) at
System.Data.Entity.Infrastructure.Interception.InternalDispatcher1.Dispatch[TTarget,TInterceptionContext](TTarget
target, Action2 operation, TInterceptionContext interceptionContext,
Action3 executing, Action3 executed) at
System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.Open(DbConnection
connection, DbInterceptionContext interceptionContext) at
System.Data.Entity.SqlServer.SqlProviderServices.<>c__DisplayClass33.b__32()
at
System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.<>c__DisplayClass1.b__0()
at
System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func1
operation) at
System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute(Action
operation) at
System.Data.Entity.SqlServer.SqlProviderServices.UsingConnection(DbConnection
sqlConnection, Action1 act) at
System.Data.Entity.SqlServer.SqlProviderServices.UsingMasterConnection(DbConnection
sqlConnection, Action1 act) at
System.Data.Entity.SqlServer.SqlProviderServices.CreateDatabaseFromScript(Nullable1
commandTimeout, DbConnection sqlConnection, String
createDatabaseScript) at
System.Data.Entity.SqlServer.SqlProviderServices.DbCreateDatabase(DbConnection
connection, Nullable1 commandTimeout, StoreItemCollection
storeItemCollection) at
System.Data.Entity.Core.Common.DbProviderServices.CreateDatabase(DbConnection
connection, Nullable1 commandTimeout, StoreItemCollection
storeItemCollection) at
System.Data.Entity.Core.Objects.ObjectContext.CreateDatabase() at
System.Data.Entity.Migrations.Utilities.DatabaseCreator.Create(DbConnection
connection) at
System.Data.Entity.Migrations.DbMigrator.EnsureDatabaseExists(Action
mustSucceedToKeepDatabase) at
System.Data.Entity.Migrations.DbMigrator.Update(String
targetMigration) at
System.Data.Entity.Internal.DatabaseCreator.CreateDatabase(InternalContext
internalContext, Func3 createMigrator, ObjectContext objectContext)
at
System.Data.Entity.Internal.InternalContext.CreateDatabase(ObjectContext
objectContext, DatabaseExistenceState existenceState) at
System.Data.Entity.Database.Create(DatabaseExistenceState
existenceState) at
System.Data.Entity.CreateDatabaseIfNotExists1.InitializeDatabase(TContext
context) at
System.Data.Entity.Internal.InternalContext.<>c__DisplayClassf1.<CreateInitializationAction>b__e()
at
System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action
action) at
System.Data.Entity.Internal.InternalContext.PerformDatabaseInitialization()
at
System.Data.Entity.Internal.LazyInternalContext.<InitializeDatabase>b__4(InternalContext
c) at System.Data.Entity.Internal.RetryAction1.PerformAction(TInput
input) at
System.Data.Entity.Internal.LazyInternalContext.InitializeDatabaseAction(Action1
action) at
System.Data.Entity.Internal.LazyInternalContext.InitializeDatabase()
at System.Data.Entity.Internal.LazyInternalContext.get_ObjectContext()
at System.Data.Entity.Database.BeginTransaction(IsolationLevel
isolationLevel) at
MassTransit.EntityFrameworkIntegration.Saga.EntityFrameworkSagaRepository1.d__81.MoveNext()
--- End of stack trace from previous location where exception was thrown --- at
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task
task) at
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task
task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at
MassTransit.Saga.Pipeline.Filters.QuerySagaFilter2.>-Send>d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown --- at
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at
MassTransit.Saga.Pipeline.Filters.QuerySagaFilter2.<MassTransit-Pipeline-IFilter<MassTransit-ConsumeContext<TMessage>>-Send>d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown --- at
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task
task) at
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task
task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at
MassTransit.Saga.Pipeline.Filters.CorrelationIdMessageFilter1.d__3.MoveNext()
--- End of stack trace from previous location where exception was thrown --- at
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task
task) at
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task
task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at
MassTransit.Pipeline.Filters.TeeConsumeFilter1.<>c__DisplayClass7_0.<<Send>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown --- at
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task
task) at
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task
task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at
MassTransit.Pipeline.Filters.TeeConsumeFilter1.d__7.MoveNext()
--- End of stack trace from previous location where exception was thrown --- at
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task
task) at
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task
task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at
MassTransit.Pipeline.Filters.MessageConsumeFilter1.<MassTransit-Pipeline-IFilter<MassTransit-ConsumeContext>-Send>d__7.MoveNext()
--- End of stack trace from previous location where exception was thrown --- at
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at
MassTransit.Pipeline.Filters.MessageConsumeFilter1.-Send>d__7.MoveNext()
--- End of stack trace from previous location where exception was thrown --- at
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task
task) at
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task
task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at
MassTransit.Pipeline.Filters.DeserializeFilter.d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown --- at
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task
task) at
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task
task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at
MassTransit.Pipeline.Filters.RescueReceiveContextFilter`1.-Send>d__5.MoveNext()
ClientConnectionId:00000000-0000-0000-0000-000000000000 Error
Number:2,State:0,Class:20
如果我使用安装了 VS 2015 的本地数据库而不是 MySQL，那么它工作得很好。它也适用于内存存储。即使异常显示找不到服务器，我也可以确认它存在并且可以访问，因为示例应用程序在选择连接字符串时首先进行检查并成功：
using (var connection = new SqlConnection(connectionString))
{
// It worked, we can save this as our connection string
return connectionString;
}
问题是否可能是因为它试图使用 SqlClient 访问 MySQL 数据库？
我正在使用 MySQL Server 5.7、EF 6.1.3、MassTransit 3.5.7 和 Automatonymous 3.5.11。
这不是 MassTransit 问题，而是 Entity Framework 问题。它应该是这样的：
如何将 Entity Framework 与 MySQL 一起使用。
您的异常清楚地表明：System.Data.SqlClient 正在抛出它。这是 SQL 服务器客户端。它还说：
Could not open a connection to SQL Server
关于如何配置EF可以参考documentation和MySQL。一般来说，你需要安装MySql.Data.Entity NuGet包并告诉EF你正在使用MySQL，然后配置正确的连接字符串：
<connectionStrings>
<add name="MyContext" providerName="MySql.Data.MySqlClient"
connectionString="server=localhost;port=3306;database=mycontext;uid=root;password=********"/>
</connectionStrings>
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework"/>
<providers>
<provider invariantName="MySql.Data.MySqlClient"
type="MySql.Data.MySqlClient.MySqlProviderServices, MySql.Data.Entity.EF6"/>
<provider invariantName="System.Data.SqlClient"
type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer"/>
</providers>
</entityFramework>
我正在使用 MassTransit（使用 RabbitMQ）和 Automatonymous 开发一个 saga。我使用 EntityFramework 作为我的商店引擎和 MySQL 作为我的数据库。每次我尝试 运行 传奇并将其状态存储在数据库中时，EF 和 MySQL 的组合都会引发异常。使用 this 示例应用程序并使用到 MySQL 数据库的连接字符串可以重现该问题。抛出的确切异常是：
System.Data.SqlClient.SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Ve rify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) ---> Syste m.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData, DbConnectionPool pool, String accessToken, Boolean applyTra nsientFaultHandling) at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConn ection, DbConnectionOptions userOptions) at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOption s userOptions) at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptio ns userOptions, DbConnectionInternal& connection) at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource
1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection) at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, Db ConnectionInternal& connection) at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource1 retry, DbConnectionOptions use rOptions) at System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource1 retry, DbConnectionOptions userOptions) at System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource1 retry) at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource1 retry) at System.Data.SqlClient.SqlConnection.Open() at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.b__36(DbConnection t, DbConnectionInterceptionContext c) at System.Data.Entity.Infrastructure.Interception.InternalDispatcher1.Dispatch[TTarget,TInterceptionContext](TTarget target, Action2 operation, TInterceptionContext interceptionContext, Action3 executing, Action3 executed) at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.Open(DbConnection connection, DbInterceptionContext interceptionContext) at System.Data.Entity.SqlServer.SqlProviderServices.<>c__DisplayClass33.b__32() at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.<>c__DisplayClass1.b__0() at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func1 operation) at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute(Action operation) at System.Data.Entity.SqlServer.SqlProviderServices.UsingConnection(DbConnection sqlConnection, Action1 act) at System.Data.Entity.SqlServer.SqlProviderServices.UsingMasterConnection(DbConnection sqlConnection, Action1 act) at System.Data.Entity.SqlServer.SqlProviderServices.CreateDatabaseFromScript(Nullable1 commandTimeout, DbConnection sqlConnection, String createDatabaseScript) at System.Data.Entity.SqlServer.SqlProviderServices.DbCreateDatabase(DbConnection connection, Nullable1 commandTimeout, StoreItemCollection storeItemCollection) at System.Data.Entity.Core.Common.DbProviderServices.CreateDatabase(DbConnection connection, Nullable1 commandTimeout, StoreItemCollection storeItemCollection) at System.Data.Entity.Core.Objects.ObjectContext.CreateDatabase() at System.Data.Entity.Migrations.Utilities.DatabaseCreator.Create(DbConnection connection) at System.Data.Entity.Migrations.DbMigrator.EnsureDatabaseExists(Action mustSucceedToKeepDatabase) at System.Data.Entity.Migrations.DbMigrator.Update(String targetMigration) at System.Data.Entity.Internal.DatabaseCreator.CreateDatabase(InternalContext internalContext, Func3 createMigrator, ObjectContext objectContext) at System.Data.Entity.Internal.InternalContext.CreateDatabase(ObjectContext objectContext, DatabaseExistenceState existenceState) at System.Data.Entity.Database.Create(DatabaseExistenceState existenceState) at System.Data.Entity.CreateDatabaseIfNotExists1.InitializeDatabase(TContext context) at System.Data.Entity.Internal.InternalContext.<>c__DisplayClassf1.<CreateInitializationAction>b__e() at System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action) at System.Data.Entity.Internal.InternalContext.PerformDatabaseInitialization() at System.Data.Entity.Internal.LazyInternalContext.<InitializeDatabase>b__4(InternalContext c) at System.Data.Entity.Internal.RetryAction1.PerformAction(TInput input) at System.Data.Entity.Internal.LazyInternalContext.InitializeDatabaseAction(Action1 action) at System.Data.Entity.Internal.LazyInternalContext.InitializeDatabase() at System.Data.Entity.Internal.LazyInternalContext.get_ObjectContext() at System.Data.Entity.Database.BeginTransaction(IsolationLevel isolationLevel) at MassTransit.EntityFrameworkIntegration.Saga.EntityFrameworkSagaRepository1.d__81.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at MassTransit.Saga.Pipeline.Filters.QuerySagaFilter2.>-Send>d__6.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at MassTransit.Saga.Pipeline.Filters.QuerySagaFilter2.<MassTransit-Pipeline-IFilter<MassTransit-ConsumeContext<TMessage>>-Send>d__6.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at MassTransit.Saga.Pipeline.Filters.CorrelationIdMessageFilter1.d__3.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at MassTransit.Pipeline.Filters.TeeConsumeFilter1.<>c__DisplayClass7_0.<<Send>b__0>d.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at MassTransit.Pipeline.Filters.TeeConsumeFilter1.d__7.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at MassTransit.Pipeline.Filters.MessageConsumeFilter1.<MassTransit-Pipeline-IFilter<MassTransit-ConsumeContext>-Send>d__7.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at MassTransit.Pipeline.Filters.MessageConsumeFilter1.-Send>d__7.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at MassTransit.Pipeline.Filters.DeserializeFilter.d__4.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at MassTransit.Pipeline.Filters.RescueReceiveContextFilter`1.-Send>d__5.MoveNext() ClientConnectionId:00000000-0000-0000-0000-000000000000 Error Number:2,State:0,Class:20
如果我使用安装了 VS 2015 的本地数据库而不是 MySQL，那么它工作得很好。它也适用于内存存储。即使异常显示找不到服务器，我也可以确认它存在并且可以访问，因为示例应用程序在选择连接字符串时首先进行检查并成功：
using (var connection = new SqlConnection(connectionString))
{
// It worked, we can save this as our connection string
return connectionString;
}
问题是否可能是因为它试图使用 SqlClient 访问 MySQL 数据库？
我正在使用 MySQL Server 5.7、EF 6.1.3、MassTransit 3.5.7 和 Automatonymous 3.5.11。
这不是 MassTransit 问题，而是 Entity Framework 问题。它应该是这样的：
如何将 Entity Framework 与 MySQL 一起使用。
您的异常清楚地表明：System.Data.SqlClient 正在抛出它。这是 SQL 服务器客户端。它还说：
Could not open a connection to SQL Server
关于如何配置EF可以参考documentation和MySQL。一般来说，你需要安装MySql.Data.Entity NuGet包并告诉EF你正在使用MySQL，然后配置正确的连接字符串：
<connectionStrings>
<add name="MyContext" providerName="MySql.Data.MySqlClient"
connectionString="server=localhost;port=3306;database=mycontext;uid=root;password=********"/>
</connectionStrings>
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework"/>
<providers>
<provider invariantName="MySql.Data.MySqlClient"
type="MySql.Data.MySqlClient.MySqlProviderServices, MySql.Data.Entity.EF6"/>
<provider invariantName="System.Data.SqlClient"
type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer"/>
</providers>
</entityFramework>