问题
I am working on Desktop application in WPF and creating SqlRepository with LocalDB to store data. I am using following tools
- Visual Studio 2013 Community with update 2
- Entity Framework 6.1.2 for Code first migration
I have created local database with Microsoft SQL Server Database File (SqlClient) configuration. Database created successfully and below is connection string fetched from Sql
Data Source=(LocalDB)\v11.0;Initial Catalog=D:\USERS\USERNAME\DOCUMENTS\TestDatabase\testdb.MDF;Integrated Security=True;Connect Timeout=30;Encrypt=False;TrustServerCertificate=False
I am using same connection string in app.config. I can view database object in SQL Server Database explorer in Visual Studio. But when run update-database command in Nuget package manager console, I am getting below error:
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
回答1:
I had similar problem and fixed it when I changed the "start-up project" from another module to the module containing references to all other projects in the solution. Right-click module >> click "Set as StartUp Project"
回答2:
Diego's answer is correct.
This problem occurs when there is no connection string in project marked as startup project. Then EF tries to connect to some default database engine to perform update. In my case it tried to use express, and for some reason it couldn't connect. And the error was thrown.
Run your "update-database" with option "-Verbose". One of the lines there shows which StartUp project is used. Check your connection string in this project, or change the startup project to the one that has correct connection string. That solves the problem.
回答3:
As explained in other answers, the problem usually comes from having the wrong Initial project in Package Manager Console.
In my case the console was ignoring the value I selected in the Default Project drop down list, and also the -StartUpProjectName parameter, and reproducing the wrong behavior of trying to connect to some default database engine, as Mikk's answer describes, in my case using a SqlExpress engine.
My problem was caused by a wrong solution configuration: if your solution has several projects and is meant to be run with the configuration option "Multiple startup projects", but you just downloaded it from your source code control repository, then it is possible that the default configuration option "Single startup project" is being applied to the solution (this config value usually is not checked-in in the source code control). In this case the Package Manager Console just ignores the startup project selected in its combo and just applies the default startup project in the solution, which may not have a connection string, as specified in Mikk's answer.
So I fixed it by changing the solution properties: Common properties / Startup project / Select Multiple startup projects instead of Single startup project, and after that the Package Manager Console would accept the Project name and update the right database.
回答4:
Try with this Connectionstring:
<connectionStrings>
<add name="DefaultConnection" connectionString="Data Source=(LocalDb)\v11.0;AttachDbFilename=D:\USERS\USERNAME\DOCUMENTS\TestDatabase\testdb.MDF;Initial Catalog=testdb;Integrated Security=True" providerName="System.Data.SqlClient" />
</connectionStrings>
回答5:
I was able to solve this by adding parameters to the update-database command:
update-database -StartupProjectName MyApp.Web -ConnectionStringName MyAppConnectStringInWebConfig
回答6:
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
This error message informs you that it is not possible to connect to SQL Server. The possible reasons and their elimination is described below:
1) SQL Server is not started. Starting of it will allow you to see your SQL Server/instance in the drop-down list of available SQL Servers.
- Go to the Start menu -> Control Panel -> Administration Tools -> Services.
- In the list of services find SQL Server (instance name, by
default it is EZPARTS5) and check its status, it must be Started
(if it is not started, then right click on SQL Server and select
Start from the context menu).
2) Firewall is blocking port 1433 (MSSQL standard port for connections). It can be disabled following the steps below:
- Go to the Start menu -> Control Panel -> Administration Tools -> Services.
- Find Firewall service, it must be disabled (if it is not, then right click the service and select Stop from the context menu).
Note: More information on this can be found on the official Microsoft site: Link
3) TCP/IP protocol is disabled for MSSQL protocols. To enable it, see the steps below:
- Navigate to SQL Server Configuration Manager in the Start menu.
- Specify settings for TCP/IP protocol in SQL Server Configuration Manager.
- Restart the computer.
Note: More information on this can be found on the official Microsoft site: Link
4) Make sure your database engine is configured to accept remote connections (If you are using centralized database):
- Open SQL Server Management Studio.
- Right click SQL Server instance -> Properties -> Connections -> Check the Allow remote connections to this server box.
- Go to the General section and check name of SQL Server specified in the Name field.
5) If you are using a named SQL Server instance, make sure you are using that instance name in your connection strings. Usually the format needed to specify the database server is machinename\instancename.
6) Make sure your login account has access permission on the database you used during login. Alternative: If you still can’t get any connection, you may want to create a SQL account on the server, a corresponding SQL user on the database in question, and just use this username/password login data to connect to SQL Server.
Referred from this link
回答7:
I solved this error changing the initial project to the Entity Project.
Look:
Update-Database -Verbose Using StartUp project 'SCVE.Web'. <-- this ir error Using NuGet project 'SCVE.EntityFramework'.
回答8:
If you are trying to connect to Sql Server instead of localdb then make sure the default connection factory in web.config file is as below:
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework">
<parameters>
<parameter value="Data Source=.\SQLEXPRESS2012; Integrated Security=True; MultipleActiveResultSets=True" />
</parameters>
</defaultConnectionFactory>
回答9:
I had this same problem with a freshly created ASP.NET project.
First I tried to set the startup project as mentioned above. There was no startup project selected and I was unable to select one.
Ultimately I updated my Visual Studio from 2015 Update 1 to 2015 Update 3 and
update-database
executed without problems.
来源：https://stackoverflow.com/questions/27768139/error-in-update-database-command-in-code-first-migration