MySQL Error 2003: Can't connect to MySQL server on 'localhost' - c#

I've been given the task of running a program that relies on a MySQL database, specifically, the 3.23.42 version. I have to install MySQL, run a .batch file that reads an SQL file (to create the required tables and such), then run the program. Seems simple enough.
I got as far as installing MySQL. I was expecting it to ask username and passwords and such, as was my experience with installing SQL Server and MySQL version 5 (and later), but it needed nothing from me. Attempts to run the .batch file, however, yields the error:
"MySQL Error 2003: Can't connect to MySQL server on 'localhost' "
So I ran Command prompt as an administrator, went to the MySQL directory, and ran "mysql". It gave me the same error as above.
Running the commands "mysqld-nt" or "mysqld" didn't do anything, so I'm assuming there's another problem at work here. Neither did I find any 'mysql' in the running services or process.
At this point, it doesn't matter if the program runs or not. I need the database up and running first.
Although I've used MySQL before, I can't say I have that much experience with it, and it had always been up and running already; this is the first time I'm deploying it myself.
Of note is that:
I haven't tried to reinstall the program yet, although I'm not sure if it will fix anything.
I've installed MyODBC-3.15.05, if it means anything (part of the instructions).
I'm using Windows 7, 32-bit (I have heard MySQL doesn't like to play nice with Windows 7).
I'm using this setup as both the server and the client; had the entire process been successful, I was to do the same thing on another computer. No computer actually uses another as a server.
I don't exactly know what services to look for in the services list.
Is there anything I can do to fix this problem?

Early versions of the MySQL installer didn't set up the windows service at all.
You might have to do it by hand.
http://dev.mysql.com/doc/refman/5.1/en/windows-start-service.html
When the service is installed you should be able to enter the following command to start the service.
net start mysql
Then all you need is to open a command window and type the following to get you into the MySQL command line where you can start writing your own queries.
mysql -uroot
I'm not terribly up on Microsoft SQL Server's flavour of SQL but I think that if you are used to using it then you might find it difficult to "get into" MySQL.
Here's a simple tutorial that gives an overview of MySQL and creating queries.
http://www.bigsoft.co.uk/blog/index.php/2012/10/04/sql-for-beginners

Check in Task Manager that mysql server is started.
Check if you can connect to the server, run telnet <hostname> <portnumber>, e.g.:
telnet localhost 3306
If you could not connect, try to find server properties (check port number), also check your firewall.

Look for the file my.ini and add bind-address = 0.0.0.0 in the [mysqld] stanza.

Well, I don't exactly know what caused this issue in the first place, but I was able to find a way to solve it. A helpful, if old - perfect in this case - tutorial I found on the web, that hopefully can help others with the same problem.
Tutorial: Install MySQL 4.0 - Windows, by Dr. Thomas E. Hicks
Computer Science Department
Trinity University
Link Here

I'm not sure if the services application is on other windows or not but if you use Windows 7, you are lucky. The easiest method is to open Start panel,in the search box,type services and hit enter.Now scroll down till you find the mysql service.In the latest version, it is named MySQL57. Right click on it and click on start.
Now you are good to use MySQL. However,you will have to perform this step every time the windows starts.

Open the MySQL Installer and click on where it says "reconfigure" next to "MySQL Server"

if it is showing error 2003 (HY000): Can't connect to MySQL server on localhost (10061) than
1.search services.msc in run
2.goto mysql properties
3.copy the mysql service name
4.start cmd as administrator
5.write: net start mysqlservicename .i.e mysql57 or etc
it will show mysql is starting.

Related

C# Blazor project running as Windows Service

I'm pretty new to this.
I have a c# blazor project which is using SQLite Database on .Net6.0
I'm trying to turn this into a windows service, so I can run it on a windows server (Win 10).
I followed steps here
but when I try running the service via "Windows Services" on my local computer, I get this error:
Windows could not start the service on Local Computer. Error 5:Access is denied.
and on the windows server it starts and immediately stops.
I checked Event Viewer and there wasn't any details about why that's it.
Do you if I need to do more stuff for it to run? specially DB wise?
I can't find good info on internet :(
I fixed it.
So, follow the link and it should work. I had some other problems with IP and Port.
and just that you don't need to change anything for your DB. You probably need to add an automatic DB migration which you can find it here.

SQL Server connection errors when moving .net app to new server

I have a number of .NET web apps on a Server 2008 machine that I'm trying to migrate to a Server 2019 machine, and some of them are giving me problems connecting to SQL Server 2016 instance on another server after moving them.
The error I get is
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. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 25 - Connection string is not valid) ---> System.ComponentModel.Win32Exception (87): The parameter is incorrect
This one is a .NET Core 2.2 web app. (.net core 2.2 server package installed on server) the connection string is like
"Server=mysqlserver\myinstance,3050;Database=Idea;Trusted_Connection=True;"
and is using Entity Framework/DbContext to connect.
The app in IIS has an app pool created for this app, set up the same as it was running on the old server: No Managed Code, Identity set as a domain user "domain\user".
Ping from new app server to database server works. Running SSMS as the domain user on the new server connects to the database fine and can view data through management studio.
So I don't know if there is something different in Server 2019 about the way it's trying to connect to SQL Server or what? I've been banging my head on this for a few days now. .NET 4.0 apps are also having the same errors trying to connect to other databases on this same instance.
The weird thing, is some other apps work fine, connecting to a different SQL 2016 instance on a different server, but they are also different .net versions, like older .NET 4.0 web apps, but they are running as app pools with different domain accounts for each app fine.
It seems all .NET Core or .net 4.0 web apps on this server are having trouble connecting to this one database instance from this server, but back on the old web app server they work fine.
Any ideas of anything else I can check?
Edit: I found the error is actually when connecting to a new SQL Server, even from the old app server it still gets the same error. I have 2 connections in this application, so I thought it was the first one, but it was actually the 2nd one. So it's something more to do with the new SQL server instance. Again, connections from SSMS work fine with this user, but not from the web app.
Edit2: After more testing, it's definitely something to do if there is Server 2019 in the mix. From 2019 app server to 2019 db server fails. From 2008 app server to 2019 db server fails. From 2019 app server to 2016 db server fails. From 2008 app server to 2016 db server succeeds.
Edit 3: I feel like I'm going crazy here. One of the apps, I tried to change ASPNETCORE_ENVIRONMENT to Development so that I could see more detailed errors on screen, so I set the appsettings.Development.json to the exact same as the appsettings.Production.json and then the connection works! Switching it back to production it gets the error again. The entire file is the exact same text. How does that even make any sense? I even tried explicitly setting the environment variable to Production instead of letting it just pick it up as the default.
Edit 4: I've solved half of the problems I've been having now.
For whatever reason, the connection string that I copied from one of the spreadsheets in the beginning had crazy hidden characters in it so that’s why it was saying the sql server didn’t exist.
I can’t see them at all in any editor and only found it by VS Code compare saying the line was different but not seeing any difference I broke it into chunks and found the spot. We found when we opened it in WordPad, that was the only place that would show it, see below.
I'm fairly sure the solution is to remove the instance name from the connection string...
"Server=mysqlserver,3050;Database=Idea;Trusted_Connection=True;"
Refer to these questions question1 & question2
"It's not necessary to specify an instance name when specifying the port."
Problem was due to hidden characters in the connection string. See my Edit 4. Other problems leftover were unrelated.
Try to create an user in the database using the same AppPool name that you used to configure your application in IIS.
Here's a "how to" create the user in the database:
https://engram404.net/grant-sql-permissions-to-iis-apppool-user/
It worked for me.
Otherwise here's an "why" it happends:
You're telling in your connectionString that it will be using an trusted connection "Trusted_Connection=True;"
If you do not want to create the user as described earlier, you should remove the Trusted_Connection=True; and use your connection string like this:
Server=mysqlserver\myinstance,3050;Database=Idea;User Id=SetYourUser;Password=SetYourPassword"
I know you happened to solve this, but still..
You can't connect to a MySQL database with System.Data.SqlClient - It is configured for an SQL database, not MySQL
You can find the MySQL Data Connector Here. (You can otherwise download it from Nuget)
If you downloaded it from Nuget, then skip this step.
After downloading the package, you can add it as a reference in your project, by right-clicking the References item in the Solution Explorer, then click Add Reference... - The Reference Manager window will then open. Click the Browse item in the left-menu, then click the Browse button, and navigate to the directory of which the package was saved.
Now, after successfully downloading and installing the package, add this line to your code:
using MySql.Data.MySqlClient;
The correct syntax for connecting to your MySQL Database, using MySql.Data.MySqlClient;, would be:
string connectionInfo = #"Server=localhost;Database=your_database;User ID=root;Password=123456";
So, overall, your code would look like:
using(MySqlConnection con = new MySqlConnection(connectionInfo))
{
con.Open();
MessageBox.Show("Successful Connection!");
}
(Code / part of answer is derived from here.)
I hope I could help anyone else with this problem :)

Setting up MySQL server on C# deployment

I have finished developing the first release of my application which uses MySQL (locally under one license and hosted under another).
Connecting the application to the hosted database works fine, i edit the connection details within my application to the hosted server details and it works fine.
However, when I try and use it locally (server:localhost etc..) i get an error stating it can not access the server. In my application, i have included the mysql DLL files, but I would prefer the user not to have to install MySQL server which is about a 100MB download (i know its quite small these days but want the install to be as pain free as possible).
I know it would be an easy fix just to add this install as a prerequisite, but i am sure there is a way to do it without this, or maybe not. Is there a script i can run which will run through and setup the server with users etc?
Any help is appreciated.
Thanks
Shaun
Connecting to a local mysql database implies there's a mysql database service running and was previously installed.
If you want a database you can distribute with your program without having to install a fully fledged database there are quite a few around such as MSSQLCE.
But otherwise, your user is going to have to install mysql on his own machine and keep it running.
Or you could use SQLLite, which is what i have had the best experience with so far.
It should be easy to refactor your Program to use this, and it takes no user setup to use it.
Hope this helps :)

Oracle: Cannot connect from entity framework

I've an oracle server, already installed on a remote server.
I've installed oracle latest provider, to use them in visual studio with entity framework.
But when I'm trying to connect to the server, I got this exception:
ORA-12560: TNS:protocol adapter error.
I'm really new to the oracle world, and I cannot find what is the problem or even how to debug it.
I saw that listeners are ups, by doing a lsnrctl status I've my listener on the port 1521.
But, I saw that i've the security like this: "Security ON: Local OS Authentication", but since I've no common users between the server and the client, can it make somes troubles?
Should I have some specials rights on my user? In local, I can connect myself with the sqldeveloper tools.
Any help would be greatly appreciated
EDIT
Some more informations:
The server runs under windows, it has the OracleXETNSListener service started. I forgot to mention, but the server firewall is off.
Edit 2
I tried to download the oracle sql developer on my workstation, and I connected myself with exactly the same informations.(I just saw that in fact sql developer use a "base" connection instead of "TNS", which seems to be used by the EF?
I ended by using the devart connector: http://www.devart.com/dotconnect/oracle/
it worked for me directly in all mode(Direct or normal). If only I did tried it this morning, I will have loosed less time.
Are you using your tns names via AD or locally on your machine? If it's local then you'll need to make sure that you have the correct connection descriptors listed in the tns names file located in the default location - this depends on Oracle version.
There are known issues around entity framework and connecting to remote instances, but these can be overcome with a l
Using the Oracle Provider, your connection string should look something like this:
Data Source={serverAddress}/xe;User Id={UserName};Password={Password};
Example:
Data Source=localhost/xe;User Id=scott;Password=tiger
I suggest you to always mention the Oracle Instance Identifier (which in the Express Edition is always xe), so you don't have to rely on your tns config settings.

Install SQL Server Express from WinForms on Button Click

Hopefully I am wording/asking this right.
I have a Winforms, .Net 3.5, app that I am trying to allow the user to kick off a SQL Server Express install from a UNC if they are a laptop. I present them with a screen on first run after the Click Once install. This screen asks them if they are a "Mobile" user. If yes then my app sets up the necessary merge replication sets between there local SQL Server Express and the correct publisher. Initially I have just had SQL Server Express be one of the prerequisites.
However this is unnecessarily bloating the install since not everyone needs SQL Server locally. Instead of having two separate Click Once installs I would like to be able to kick off installing SQL Server from an UNC path if they choose Mobile on my start up screen.
It's not as simple as a Process.Start() is it? Oh, this is an internal app only. Everything is done on our network.
It is as simple as Process.Start().
However, you may want to check the installer documentation and pass command-line options for a silent install.

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