Good morning guys,
I feel quite silly to ask this question, but I have looked everywhere and possibly at all questions in this matter and could not find a solution that would work for me.
Long story short.
I am using a local database called TestDB.mdf in windows form application. The application is designed to do (as per current) two simple things.
1. Import data from excel document into the database - which I don't have any issues with.
and...
2. Clear all data stored in that database - this is where I am struggling
For the import data into the database (point 1) I am using two connection strings. One for excelConnectionString
string excelConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source= " +
"C:\\Users\\User.AR\\Desktop\\export.xls; " +
"Extended Properties=\"Excel 8.0;HDR=YES;IMEX=1;\"";
and second for sqlConnectionString
string sqlConnectionString = #"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=c:\users\arkadiusz.rzepka\source\repos\Database_application\Database_application\TestDB.mdf;Integrated Security=True";
Then I use SqlBulkCopy to import all data and all is working like a charm.
Now the issue I can see is that I cannot open a connection to clear all data from the same database.
I have navigated to properties of my database to find connection string and this has been presented in the below format:
Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Users\User.AR\source\repos\Database_application\Database_application\TestDB.mdf;Integrated Security=True
I have had to amend the above connection string as I was getting errors such as missing provider, should be like Provider=SQLOLEDB, after adding a provider, I have had to change Integrated Security = SSPI, and now I am getting error such as SQL Server does not exist or access denied
My code just to check if the connection was opened is presented below and I would be grateful if you could advise of what I am doing wrong.
private void DeleteAllRecords()
{
string connectionString = #"Provider=Sqloledb;Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Users\User.AR\source\repos\Database_application\Database_application\TestDB.mdf;Integrated Security=SSPI";
using (OleDbConnection connection = new OleDbConnection(connectionString))
{
try
{
connection.Open();
MessageBox.Show("Connection openned successfully!");
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
If you run this in the command prompt.
SqlLocalDB.exe i "MSSQLLocalDB"
You will get the instance pipe name. You should be able to use that in your OLEDB connection. This has worked for me when connecting Excel using OLEDB connection to my MSSQLLocalDB.
Name: MSSQLLocalDB
Version: 13.1.4001.0
Shared name:
Owner: Foo\Foo.Bar
Auto-create: Yes
State: Running
Last start time: 18/03/2021 09:00:34
Instance pipe name: np:\\.\pipe\LOCALDB#DA1FAFF6\tsql\query
So my final connection string in excel looked like this.
provider=SQLOLEDB;initial catalog=IpsosDC;data source=np:\\.\pipe\LOCALDB#DA1FAFF6\tsql\query
Try using double bar on the paths of your connection strings, instead of one. So it would be like this:
string connectionString = #"Provider=Sqloledb;Data Source=(LocalDB)\\MSSQLLocalDB;AttachDbFilename=C:\\Users\\User.AR\\source\\repos\\Database_application\\Database_application\\TestDB.mdf;Integrated Security=SSPI";
Related
I have the following code.
private void CreateDBFFile()
{
string connection = ConfigurationManager.ConnectionStrings["conn"].ConnectionString;
using (OleDbConnection dbconnection = new OleDbConnection(connection))
using (OleDbCommand command = dbconnection.CreateCommand())
{
dbconnection.Open();
command.CommandText = "CREATE TABLE Test (Id Integer, Changed Double, Name Text)";
command.ExecuteNonQuery();
}
}
My web.config file has connection string
<connectionStrings>
<add name="conn"
connectionString="Provider=Microsoft.Jet.OLEDB.4.0; Data Source=k:\temp1"
providerName="System.Data.OleDb" />
</connectionStrings>
I am trying to create a dbf file on my K drive. I keep getting an error on my dbConnection.Open() statement saying:
The Microsoft Jet database engine cannot open the file 'k:\temp1'. It is already opened exclusively by another user, or you need permission to view its data.
K:\ is not a mapped drive. I gave network service userName to temp1 folder by going under security tab. I also gave modify rights to the Network service. Still keep getting this error. I also tried to put the entire above code in console application, that didn't work either. I keep getting the same error.
Any help will be greatly appreciated.
I am not sure what I am doing wrong, If I use the connection string shown here, my application works fine.
SqlConnection conn = new SqlConnection();
string DbPath = Application.StartupPath;
DbPath = DbPath.Substring(0, DbPath.LastIndexOf("\\bin"));
DbPath = DbPath + "\\MyDatabase.mdf";
conn.ConnectionString = "Data Source=.\\EXPRESS2008;AttachDbFilename=" + DbPath + ";Integrated Security=True;User Instance=True";
but if I use connection string here, it's not inserting data into MyDatabase table
conn.ConnectionString = Properties.Settings.Default.MyDatabaseConnectionString;
My app.config is
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
</startup>
<connectionStrings>
<add name="ERPSystem.Properties.Settings.MyDatabaseConnectionString"
connectionString="Data Source=.\EXPRESS2008; AttachDbFilename=|DataDirectory|\MyDatabase.mdf;Integrated
Security=True;User Instance=True"
providerName="System.Data.SqlClient" />
</connectionStrings>
INSERT statement and preceding code:
comm = new SqlCommand("CreateUser", MyConnection.MyConn("Open"));
comm.CommandType = CommandType.StoredProcedure;
comm.Parameters.Add("#UserName", SqlDbType.VarChar).Value = userName.Text;
comm.Parameters.Add("#Password", SqlDbType.VarChar).Value = userPassword.Text;
comm.Parameters.Add("#UserRole", SqlDbType.VarChar).Value = UserRole.SelectedItem.ToString();
comm.ExecuteNonQuery();
This is the code to get the connection
class MyConnection
{
public static SqlConnection MyConn(string str)
{
SqlConnection conn = new SqlConnection();
try
{
//get application path
string DbPath = Application.StartupPath;
if (Program.RunFrEn == true) //bool var
//remove string after bin folder
DbPath = DbPath.Substring(0, DbPath.LastIndexOf("\\bin"));
//add database name with new path
DbPath = DbPath + "\\MyDatabase.mdf";
//generate new connection string for database
conn.ConnectionString = "Data Source=.\\EXPRESS2008;AttachDbFilename="
+ DbPath
+ ";Integrated Security=True;User Instance=True";
//conn.ConnectionString = Properties.Settings.Default.MyDatabaseConnectionString;
if (str == "Open")
{
if (conn.State == ConnectionState.Closed)
conn.Open();
}
else
{
if (conn.State == ConnectionState.Open)
conn.Close();
}
}
catch (System.Data.SqlClient.SqlException ex)
{
MessageBox.Show(ex.Message);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
return conn;
}
}
I am not getting any error
Thank you
The whole AttachDbFileName= approach is flawed - at best! When running your app in Visual Studio, it will be copying around the .mdf file (from your App_Data directory to the output directory - typically .\bin\debug - where you app runs) and most likely, your INSERT works just fine - but you're just looking at the wrong .mdf file in the end!
If you want to stick with this approach, then try putting a breakpoint on the myConnection.Close() call - and then inspect the .mdf file with SQL Server Mgmt Studio Express - I'm almost certain your data is there.
The real solution in my opinion would be to
install SQL Server Express (and you've already done that anyway)
install SQL Server Management Studio Express
create your database in SSMS Express, give it a logical name (e.g. MyDatabase)
connect to it using its logical database name (given when you create it on the server) - and don't mess around with physical database files and user instances. In that case, your connection string would be something like:
Data Source=.\\SQLEXPRESS;Database=MyDatabase;Integrated Security=True
and everything else is exactly the same as before...
Also see Aaron Bertrand's excellent blog post Bad habits to kick: using AttachDbFileName for more background info.
I also had fighted long time with same problem. And I saw many same questions & answers.
You're using |DataDirectory|. I assume you can get values from the DB file and you don't get error to run insert command but the values are not inserted into the DB file.
This is absolutely my private idea and my private conclusion is that this behavior is normal as |DataDirectory| does. I mean a data file of an application should be protected from manipulation once after deployment. The 'Data' file should provide data inside the file so that we can read the data.
Therefore, I coded to create a localDB .MDF file (SQL Server 2014) from users' side so that my applications can utilize the localDB to write and read data. My application automatically downloads data from cloud server which are we need to update frequently. On the other side, I put big and already fixed data into |DataDirectory| .MDF file, I mean inserted big data for read only and add the .MDF file to my project before deployment.
Hope my experience helps.. But, please keep in mind again that this is really my private opinion and I might be totally wrong and my experience is limited only to localDB. But again, I couldn't find a Microsoft's official document mentioning this behavior.
Do you have only 1 option like |DataDirectory|? Did this work to insert before? Is this code by you wrote on your own? If possible, try to find another option rather than |DataDirectory| to connect to the SQL Server database. I use a cloud SQL server with IP address but I can't understand why you use |DataDirectory|. There might be many various options as connection strings to SQL Server Express.
I am using this code but getting an error of 'Object reference not set to an instance of an object.' at con.open() ? what am I doing wrong ?
I have already download and installed ODAC component version 10 , 11 ,12 trying each one at the failure of the latest one but still same error
using Oracle.DataAccess.Client;
namespace WindowsFormsApplication1
{
class OraTest
{
public OracleConnection con = new OracleConnection();
public void Connect()
{
con.ConnectionString = "Data Source=(DESCRIPTION= (ADDRESS = (PROTOCOL = TCP)(HOST =myip) (PORT = myport))(CONNECT_DATA = (SERVER = dedicated)(SERVICE_NAME = mydb)));User ID=myid;Password=mypass;";
con.Open(); //error here
}
public void Close()
{
con.Close();
con.Dispose();
}
}
Please go through this link
Getting Started with Oracle Data Provider for .NET (C# Version)
http://www.oracle.com/webfolder/technetwork/tutorials/obe/db/dotnet/GettingStartedNETVersion/GettingStartedNETVersion.htm
If you add a try/catch block in Connect(), you'll be able to catch the error.
For example:
When opening an oracle connection, connection object is null
I added the try catch block, and it returned ORA12154 - TNS could not
be resolved. After some research, I added an SID to my tnsnames.ora
file in my ODP for .NET Oracle home path, and it worked
See also Troubleshooting Oracle Net Services for troubleshooting possible connection issues from Oracle clients (such as your C# program).
But your first step is absolutely to determine the Oracle-level error (for example, ORA-12543 (could not connect to server host) or TNS-12514 (could not find service name)
MSDN: OracleException Class
public void ShowOracleException()
{
OracleConnection myConnection =
new OracleConnection("Data Source=Oracle8i;Integrated Security=yes");
try
{
myConnection.Open();
}
catch (OracleException e)
{
string errorMessage = "Code: " + e.Code + "\n" +
"Message: " + e.Message;
System.Diagnostics.EventLog log = new System.Diagnostics.EventLog();
log.Source = "My Application";
log.WriteEntry(errorMessage);
Console.WriteLine("An exception occurred. Please contact your system administrator.");
}
}
It's significant that con.ConnectionString = xyz works, but the following `con.Open()" fails. This means .Net is creating the C# object, but Oracle/TNS is failing when you try to use it.
ADDITIONAL SUGGESTIONS:
Re-read
When opening an oracle connection, connection object is null.
Read all of the suggestions, including the one about "Data Source in your connection string".
Focus on your connection string. It couldn't hurt to specify the connection string in your OracleConnection() constructor, if possible. Here's another link:
ODP.NET Connection exception
It would be great if you can verify connectivity from your PC with some other Oracle client, besides your C#/.Net program. To verify you're talking to the right TNS host and service, with the correct username/password. For example, maybe you have SQLDeveloper or sqlplus.
Finally, re-read the TNS troubleshooting link:
https://docs.oracle.com/cd/E11882_01/network.112/e41945/trouble.htm#NETAG016
What worked for me with the same error was to simply switch from the 'plain' Oracle DataAccess library, to the 'Managed' version.
This is an extemely easy change to make -
Add a Reference in your c# project to the Oracle.ManagedDataAccess library
Replace the existing use statements at the top of your Oracle client code with the following:
using Oracle.ManagedDataAccess.Client;
using Oracle.ManagedDataAccess.Types;
Include the Oracle.ManagedDataAccess.dll file with your exe
Ok, so I've been looking everywhere on how to connect a microsoft access database to a C# command line application. I have experience in visual studio when I was doing visual basic so I connected the database to the project via the "add new data source" menu. Now I'm here I have no clue how to declare the connection and open it. I know the basics of SQL code so that's not really a problem right now, it's just the connecting part. Looking around, I've found this:
using System.Data.SqlClient;
string connectionString = null;
connectionString = ;
SqlConnection cnn ;
cnn = new SqlConnection(connectionString);
try
{
cnn.Open();
Console.WriteLine("Connection Open!");
cnn.Close();
}
catch (Exception ex)
{
Console.WriteLine("Error: Connection Cannot be Opened!");
}
But I have no clue what this does. If this is wrong can someone please correct me and explain it. Please keep it as simple as possible.
You simply use OleDb* instead of Sql*. ie:
string connectionString = #"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=c:\MyFolder\Northwind.accdb";
using( OleDbConnection cnn = new OleDbConnection(connectionString))
{
try
{
cnn.Open();
Console.WriteLine("Connection Open!");
cnn.Close();
}
catch (Exception ex)
{
Console.WriteLine("Error: Connection Cannot be Opened!");
}
}
PS: I wouldn't recommend you using access as if it is a database. It is not a database. It is the wolf disguised like a sheep. If you don't care about your data then OK.
Setting the connectionString = null won't work!
See: http://www.connectionstrings.com/ for help on connection strings. This is really a great site.
And if you want a connection to Access, you need an OleDbConnection, not a SqlConnection. The latter is used for connections to SQL-Server.
You can find an example here: Getting values back from OleDbDataReader reading from Access database.
This is the 1st time I am using C# connection with db, also I dont use access.
I just want to know the initial steps required to connect the access db to visual studio C# windows application.
I have searched though the internet, It helped a lot. I cant find my mistake in the code. I think I am missing some steps in establishing the connection with the db.
here is the error that appears when I try to run the program "'\f38910\Users\kainat.baig\Desktop\AAA\Database101' is not a valid path. Make sure that the path name is spelled correctly and that you are connected to the server on which the file resides."
CODE:
OleDbConnection bookConn;
OleDbCommand oleDbCmd = new OleDbCommand();
String connParam = #"Provider=Microsoft.Jet.OLEDB.4.0;Data Source= \\f38910\Users\kainat.baig\Desktop\AAA\Database101; Persist Security Info=False";
public Form1()
{
bookConn = new OleDbConnection(connParam);
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
bookConn.Open(); //*ERROR LINE
oleDbCmd.Connection = bookConn;
bookConn.Close();
}
First your file name does not have the file extension name like .mdb
Database101\MyDB.mdb
Second, if it is in a network. Would it be better if you net use first in you DOS prompt to assign a drive letter for your network, like:
net use z: \\f38910\Users\kainat.baig\Desktop\AAA\Database101 your_password /USER:your_account
Then your connection string will be shorter then:
String connParam = #"Provider=Microsoft.Jet.OLEDB.4.0;Data Source= z:\MyDB.mdb; Persist Security Info=False";
If the file extension by the way is .accdb instead of .mdb it should be:
String connParam = #"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=z:\MyDB.mdb;;Persist Security Info=False;"
Or simply your path is simply wrong.
Go to windows explorer and just clink on the path where your file is and copy paste it.
You forget to add .mdb after database name or .accdb if you are using Microsoft Office Access 2007 or higher database but, for that you have to change Provider also.
String connParam = #"Provider=Microsoft.Jet.OLEDB.4.0;Data Source= \\f38910\Users\kainat.baig\Desktop\AAA\Database101.mdb; Persist Security Info=False";
Or you can use connection string like this
String connParam = #"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=\\f38910\Users\kainat.baig\Desktop\AAA\Database101.mdb;User Id=admin;Password=;"
EDITED:
for ACCESS 2010
#"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=\\f38910\Users\kainat.baig\Desktop\AAA\Database101.accdb"