Develop Reference

Connection to Oracle database not working

I am currently working on a project with someone. We are connecting to a oracle Database using the NuGet Package Oracle.ManagedDataAccess.Core.
We are connecting using a connection string that looks like this:
"User Id={this._dbUser};Password={this._dbPassword};Data Source={this._dbServer};"
The Parameters we pass on are correct we checked multiple times.
At first I got a Connection Timed out error which we fixed by adding persist security info=false;Connection Timeout=120; to the connection string.
At first it seemed to be working but then we encountered a new error.
This time it was saying:
Oracle communication: Connection to server could not be established or connection string not parsed
(Might not be 100% accurate because I had to translate it from German to English)
We could not find a solution for this error but we discovered that the error only gets thrown when we run the code on my machine. His is doing totally fine and can connect without any problems.
Could it be that I have some settings set on my machine that would prevent me from accessing the Database?

U-SQL data source as SQL Server inside a UDF

I need to extract rows from a SQL table where some columns are encrypted using SQL Server's new 'Always Encrypted' feature. I see that I cannot use the 'AZURESQLDB' DataSource feature and there needs to be decryption done before reading the data in plain text. Are there plans to add this capability?. Meanwhile, I tried to write a user defined function that will do the same operation(connect, decrypt data and return object) in a registered assembly but when it runs, I get the following error:
Inner exception from user expression: 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: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)
I have checked the code and everything seems correct. The connection string is used by the SqlConnection object and works fine in all other applications. I am guessing that the connectivity to external data sources from within a UDF is blocked. Is there any way around this?

Are you using the DATA SOURCE in U-SQL for representing your SQL Server instance and you cannot get it to read encrypted data? If so, please file a feature request at http://aka.ms/adlfeedback.
You cannot call out to network resources directly from within U-SQL user code for the reasons explained here.

One way around this might be to create a stored procedure which does the hard work, the decryption then renders the data. Then use Azure Data Factory with a Stored Proc Task to access the decrypted data and move what you need to the Data Lake - not including the secure data. From there you could then access it using a U-SQL script. One idea? Let me know if you need me to work up more of an example.

Can't connect to local SQL Server 2014 from C# using OleDbConnection

I see several answers to problems similar to mine, but I don't know enough to adapt those answers to my problem. So, with apologies for what is probably a duplicate question, here goes:
I'm trying to connect to a Microsoft SQL 2014 database on my local machine from a ASP.NET application. The code is:
oCN = new OleDbConnection(connectionString);
With a connectionString of:
Provider=SQLNCLI11; Server=FLIPPY\SQLEXPRESS; Trusted_Connection=yes;
Database=FingerTipDisplay; User Id=<my user id>; Password=<my password>
oCN is as follows after the call to new OleDbConnection():
- oCN {System.Data.OleDb.OleDbConnection} System.Data.OleDb.OleDbConnection
CanRaiseEvents true bool
ConnectionString "Provider=SQLNCLI11; Server=FLIPPY\\SQLEXPRESS; Trusted_Connection=yes; Database=FingerTipDisplay; User Id=<my user id>; Password=<my password>" string
ConnectionTimeout 15 int
Container null System.ComponentModel.IContainer
DataSource "" string
Database "" string
DbProviderFactory null System.Data.Common.DbProviderFactory
DesignMode false bool
+ Events {System.ComponentModel.EventHandlerList} System.ComponentModel.EventHandlerList
Provider "SQLNCLI11" string
+ ServerVersion 'oCN.ServerVersion' threw an exception of type 'System.InvalidOperationException' string {System.InvalidOperationException}
Site null System.ComponentModel.ISite
State Closed System.Data.ConnectionState
+ Static members
+ Non-Public members
I believe my SQL server is running correctly:
I can't get SQL Server Agent to start, and am not sure if that's causing my problem or not. From other replies I've ensured TCP/IP is enabled:
This is my database structure:
and I think that the user name and password I'm connecting has the right permissions from the dbo schema:
I've checked the SQL Server logs and don't see anything that looks like a failed login attempt, and I don't know where to look in the OleDbConnection object for feedback on why the connection failed. I'm working on someone else's code, so I'm reluctant to use SqlConnection() since I don't know the implications for the rest of the app.
I'm guessing that the problem is in the connection string, but I don't know what to use for that. I've tried SQLOLEDB as the provider, and I've tried using Initial Catalog instead of Database.
Thanks in advance for your help.
Update:
Thanks for all the help so far. oCN.Open() was throwing an OleDbException immediately, and it was:
"Login failed for user 'riehlj2002#gmail.com'."
I made some changes to the connection string based on the advice below...this is what it looks like right now:
Provider=SQLNCLI11; server=localhost; DataSource=localhost\SQLEXPRESS; Database=FingerTipDisplay; user id=<my user id>; password=<my password>
Now it doesn't throw the exception right away, but it still throws it. This is the exception I get:
{"Login timeout expired\r\nA network-related or instance-specific error has occurred while establishing a connection to SQL Server. Server is not found or not accessible. Check if instance name is correct and if SQL Server is configured to allow remote connections. For more information see SQL Server Books Online.\r\nNamed Pipes Provider: Could not open a connection to SQL Server [2]. \r\nInvalid connection string attribute"}
A few things I notice.
First, if I change server to localhost\SQLEXPRESS I get an immediate exception telling me that I have an invalid connection string attribute, so the advice in this link doesn't work for me.
Second, it doesn't seem to matter whether I use localhost or my machine name...it does the same thing.
Third, I was surprised to see something in there about the named pipes protocol. I went into the SQL Server Configuration Manager and enabled that protocol...it didn't make a difference.
Fourth, it doesn't make a difference whether I specify DataSource or not in terms of the exception, but intuitively it seems like I have to specify the server instance somewhere so I've left it in.
Fifth, if I change the provider to SQLOLEDB I get a different exception: {"[DBNETLIB][ConnectionOpen (Connect()).]SQL Server does not exist or access denied.\r\nInvalid connection string attribute"}, so I think I'm on the right track with SQLNCLI11.
Sixth, in the OleDbConnection object the DataSource and Database properties are both empty strings despite their being specified in the connection string.
Finally, the very last part of the exception I'm getting now talks about an invalid connection string attribute, but I removed each one in turn and either got the same exception or got another one that I've already described.
Again, thanks for the help.

You are using Trusted_Connection=yes but specifying a username and password. It's either one or the other, I don't think you can do both in the same connection string (not sure if that'd raise any errors, but the supplied user and password would be at least ignored, for sure).
In your case, since you are using a user and a password, you'd need to set Trusted_Connection to no (or false), or just not set it (it should be false by default)

OK, I found the problem. My original connection string wasn't finding the database, so I got no additional information in the server logs. I changed the connection string to:
Provider=SQLNCLI11; server=localhost\SQLEXPRESS; Database=FingerTipDisplay; user id=<my user id>; password=<my user id>
And then I found in the server log that it was configured to use Windows authentication only. I used this link to allow SQL server authentication, and all is now well. Your answers got me going in the right direction...thanks.

Can connect mysql database via navicate but cant from c# application

here is all info.
Step 1
Step 2- Error Msg
Step 3- connection String
I have tried without using port number but the problem is same. There is IP restrictions for remote login. but if it is because of IP restriction why am I able to connect with Navicat.
Code of C# where i'm getting error.

As per step 1 it seems the connection has been successfully established, but still you are unable to connect to the specific database. Check the name of the database or confirm that the database exists with the name supplied in the connection string. You can do that even by creating a connection from Navicat. If the database exists you will find it there.
Cheers

Maybe you should invoke mysqlcon.Open() before using mysqlcon.

Data source for connection string

What connection string should I use if SSMS connects to it using simply machine name, without instance name?
I mean it connects using the following string: PCName
I used to connect using PCName/SQLExpress. I cannot set correct connection string in my app in order to connect app to database on this machine.
How can I check what data source I should use? I've checked in Sql Server configuration that server instance named as SQLEXPRESS.
So I tried data source as:
.\SQLEXPRESS
PCName\SQLEXPRESS
.
I'm trying to connect to a service-based database, located in my app folder. So I'm using the following connection string:
data source=PCName;attachdbfilename=|DataDirectory|\spareparts.mdf;integrated security=true;user instance=true;multipleactiveresultsets=true;App=EntityFramework;

If SSMS connects via PCName then your application should be able to use Data Source=PCName. However it depends on whether your application is on the same machine as SSMS or not. If on a different machine it might not be able to connect for a variety of reasons. We can't speculate what the problem might be if all you do to describe the issue is "It won't connect" - what does that mean? Do you get an error message? If so, what is it? Make sure:
SQL Browser service is started
TCP/IP is enabled
Add Network=DBMSSOCN; to the connection string
You've also tried the IP address in addition to PCName
Firewall isn't blocking the SQL Server port