sqlite c#: database connection not valid - c#

I have a sqlite database file in .s3db, It has all the tables and data already populated in it. I am trying to connect to to the database use sqliteConnection. But it does not seem to work..I have added the reference of sqlite.dll, does c# needs some other reference to make the connection? If I make a new sqlite db, it is made as xyz.sqlite, maybe it is not recognizing the database extension.
This is how I am making the connection:
// Creates a connection with our database file.
public void connectToDatabase()
{
//this.dbConnection = new SQLiteConnection(#"data source=Fut_Autobuyer_2012.s3db;version=3;");
string dbConnectionString = #"Data Source=Fut_Autobuyer_2012.s3db";
this.dbConnection = new SQLiteConnection(dbConnectionString);
}
This is what I get when the connection is made:
Database connection not valid for getting number of changes.
Database connection not valid for getting last insert rowid.
Database connection not valid for getting maximum memory used.
Database connection not valid for getting memory used.

It looks like you must open database connection:
using (var connection = SQLiteFactory.Instance.CreateConnection())
{
Debug.Assert(connection != null, "connection != null");
connection.ConnectionString = connectionString;
connection.Open();
try
{
using (var command = connection.CreateCommand())
{
// Execute connection
}
}
finally
{
connection.Close();
}
}

Related

Connect and insert data from my computer to server's MySQL DB table with the help of C#.NET

I want to connect with a server's MySql DB(cpanel) . Though there are no errors every time I'm getting a message for Messegebox : unable to connect to any of the specified any of the MySql hosts.
using MySql.Data.MySqlClient;
connString = "SERVER = ********;PORT=3306;DATABASE=********;UID=**********;PASSWORD=*********";
try
{
conn = new MySqlConnection();
conn.ConnectionString = connString;
conn.Open();
MessageBox.Show("Server is online");
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{ MessageBox.Show(ex.Message);}
If you try to connect to your MySQL server externally, external connections need to be enabled.
Be aware that it is a security hole if you provide your app to others which contain the DB information. To go around that, you need to create a Web-API.
The first step to connect to your app to a remote server MySql Server is verify if it allows external connections, for default the root user is locked, to allow local you can try to connect with the root user typing the following command in MySql:
GRANT ALL PRIVILEGES ON *.* TO 'root'#'%' IDENTIFIED BY 'password' WITH GRANT OPTION;
FLUSH PRIVILEGES;
'root': You can change it with your user.
'%': allows all connections, you can limit it typing an IP.
Second step is verify your MySql .net connector
Cheers!
I would look into using ConnectionStringBuilder. Also note the use of 'using'. This will ensure resources are disposed once finished with.
private MySqlConnectionStringBuilder sConnString = new MySqlConnectionStringBuilder
{
Server = "",
UserID = "",
Password = "",
Database = ""
};
private void Test(){
// open connection to db
using (MySqlConnection conn = new MySqlConnection(sConnString.ToString()))
{
using (MySqlCommand cmd = conn.CreateCommand())
{
try
{
conn.Open();
cmd.CommandText = "SELECT * FROM foo WHERE OrderID = #OrderID";
// Add any params
cmd.Parameters.AddWithValue("#OrderID", "1111");
cmd.Prepare();
cmd.ExecuteNonQuery();
}
catch (Exception e)
{
MessageBox.Show(e.ToString());
return;
}
}
}
}

Changing Connection string from one database to another in c#.net

I am using connection string in Global.cs which is static.But i want to make change database connection during run time. So I am storing data base name in ini file and am changing it in run time. I wants to point my connection string to the next database which i updated. I am able to fetch that database name from ini file.
I tried to change the connection string db1 to db2. Any one please tell me how can i change that connection String to another database in run time...
iam using Connection string in static Global.cs file that is
static Global()
{
try
{
ConnectionStringSettingsCollection getConFromAPP = ConfigurationManager.ConnectionStrings;
string con = getConFromAPP["DatabseConnection"].ConnectionString;
conStrYearDatabase = new SqlConnection(con);
conStrYearDatabase.Open();
}
catch (Exception e1)
{
Console.Write(e1.Message);
}
}
how to run the same static class file for the second time during run time
Should not be a tough ask.
Close the open connection.
Change your connection string on the existing Connection object.
Reopen the connection.
OleDbConnection connection = new OleDbConnection("old conn string>");
connection.Open();
//do somthing with db 1
connection.Close();
//Change the connection string
connection.ConnectionString="<new connection string>";
connection.Open();
//do somthing with db 2
connection.Close();

How to test connection to a data source in SSAS using C#

I have a database in Analysis Services on a remote server. This contains a data source for another database located on another remote server.
I am trying to write a connectivity test using C# which will check the database connection between the two databases.
I have been unable to do this using ADOMD.NET. I'm currently looking at using SMO to do this but I haven't had any luck so far.
I would greatly appreciate any advice or suggestions.
Update:
After further research, I have come up with the below test (Please note that I intend to add more try..catch blocks and Assertions later).
Also, this uses C:\Program Files\Microsoft SQL Server\100\SDK\Assemblies\Microsoft.AnalysisServices.DLL to access the Server, Database and
DataSource classes.
class ConnectivityTests
{
// Variables
String serverName = "";
String databaseName = "";
String dataSourceName = "";
[Test]
public void TestDataSourceConnection()
{
// Creates an instance of the Server
Server server = new Server();
server.Connect(serverName);
// Gets the Database from the Server
Database database = server.Databases[databaseName];
// Get the DataSource from the Database
DataSource dataSource = database.DataSources.FindByName(dataSourceName);
// Attempt to open a connection to the dataSource. Fail test if unsuccessful
OleDbConnection connection = new OleDbConnection(dataSource.ConnectionString);
try
{
connection.Open();
}
catch (OleDbException e)
{
Assert.Fail(e.ToString());
}
finally
{
connection.Close();
}
}
I believe that this test is sufficient for my testing (Once I've added some more try..catch blocks and Assertions). If the test passes, it means there are no connectivity issues between my machine and both servers, which implies that there shouldn't be any connectivity issues between the servers.
However, I have been unable to work out how to test the connection between the two servers directly and I am interested if anyone knows a way of doing this.
The best solution I have come across to doing this connectivity test is below:
Please note that this requires the Microsoft.AnalysisServices.DLL to be added as a reference.
class ConnectivityTests
{
// Variables
String serverName = "";
String databaseName = "";
String dataSourceName = "";
[Test]
public void TestDataSourceConnection()
{
try
{
// Creates an instance of the Server
Server server = new Server();
server.Connect(serverName);
// Gets the Database from the Server
Database database = server.Databases[databaseName];
// Get the DataSource from the Database
DataSource dataSource = database.DataSources.FindByName(dataSourceName);
// Attempt to open a connection to the dataSource. Fail test if unsuccessful
OleDbConnection connection = new OleDbConnection(dataSource.ConnectionString);
connection.Open();
}
catch (Exception e)
{
Assert.Fail(e.ToString());
}
finally
{
connection.Close();
}
}
}

I can't connect to my local SQL Server database

I'm currently learning ADO.NET on C#. I'm learning by a book and tutorials that I found online. I wanted to try some of the samples to get myself familiarized with the whole SQL connnection and command objects and so on. Hence, I tried this:
namespace ConsoleApplication
{
class SqlDemo
{
public void InitConnection ()
{
string connString = #"data source=C:\SQL Server 2000 Sample Databases; database=northwnd; integrated security=SSPI";
SqlConnection conn = null;
try
{
conn = new SqlConnection (connString);
conn.Open ();
Console.WriteLine ("DataBase connection established");
}
catch
{
Console.WriteLine ("DataBase connection not established");
}
finally
{
if (conn != null) conn.Close ();
}
Console.ReadKey (true);
}
static void Main (string[] args)
{
SqlDemo d = new SqlDemo ();
d.InitConnection ();
}
}
}
And no matter how I try, I can connect to the local database. "data source=(local)" don't work.
A couple of things:
1) It looks like you may have a typo in your database name. It should probably be:
database=northwind
2) Your data source should be (local) or . OR you may have an instance installed, in which case you may need to include the instance name as well, such as .\SQLExpress or .\SQLServer.
If you wish to connect to a database file using a path:
Server=.\SQLExpress;AttachDbFilename=|DataDirectory|mydbfile.mdf; Database=dbname;Trusted_Connection=Yes;
From: http://www.connectionstrings.com/sql-server-2008
However, you may also need to "Attach" the database to Sql Server. In Management studio, right click the Databases folder and select "Attach..."
If you are using SQL Server 2000, then just put 'local' or simply '.' (exclude the quotes) for the data source. And you have a typo in the database name. It should be 'Northwind'

How can I connect to a SDF database? No connection string I try seems to work

I've tried literally 50+ different attempts at my connection string for my local database and nothing seems to work. I'm essentially just trying to open a connection the database file so I can dump in the data I've pulled out of my excel spreadsheet. I'm using Visual C# making an offline winform application.
No matter what connection string I try in my app.config, it always fails when it tries to write "dReader" to the database.
The error is usually this depending on what string I try:
"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've gone through many online examples and resources and none seem to work. I'm hoping someone here can point out why it's failing.
Here is my app.config in its latest form:
<connectionStrings>
<add name="DDP_Project.Properties.Settings.DDP_DatabaseConnectionString"
connectionString="Data Source=E:\Other DDP Projects\DDP_Project_SDF\DDP_Project\DDP_Database.sdf;"
providerName="Microsoft.SqlServerCe.Client.3.5" />
</connectionStrings>
Here is my form code:
private void Profiles_Click(object sender, EventArgs e)
{
profilesDialog.FileName = "[YOUR_UPLOAD_FILE_HERE]";
var result = profilesDialog.ShowDialog();
if (result == DialogResult.OK)
{
HandleFileSelection();
}
}
private void HandleFileSelection()
{
var file = profilesDialog.FileName;
// Create a connection to the file datafile.sdf in the program folder
string dbfile = new System.IO.FileInfo(System.Reflection.Assembly.GetExecutingAssembly().Location).DirectoryName + "\\DDP_Database.sdf";
SqlCeConnection connection = new SqlCeConnection("datasource=" + dbfile);
string strConnection = ConfigurationManager.ConnectionStrings["DDP_Project.Properties.Settings.DDP_DatabaseConnectionString"].ConnectionString;
//Create connection string to Excel work book
string excelConnectionString = string.Format(
#"Provider=Microsoft.Jet.OLEDB.4.0;
Data Source=""{0}"";
Extended Properties=""Excel 8.0;HDR=YES;""", file
);
//Create Connection to Excel work book
OleDbConnection excelConnection = new OleDbConnection(excelConnectionString);
OleDbCommand cmd = new OleDbCommand("SELECT [ID],[STATUS],[FAN_NUM],[PROFILE_NAME],[DESTINATION_HOST],[USER_ID],[USER_PASSWORD],[PROTOCOL],[PORT],[PATH],[CONTACT_NAME],[CONTACT_EMAIL],[CONTACT_PHONE],[CONTACT_ALT_PHONE],[CONTACT_CITY],[CONTACT_STATE],[CONTACT_CONTACT_TIME] FROM [Sheet1$]", excelConnection);
excelConnection.Open();
OleDbDataReader dReader;
dReader = cmd.ExecuteReader();
SqlBulkCopy sqlBulk = new SqlBulkCopy(strConnection);
sqlBulk.DestinationTableName = "Profiles";
sqlBulk.ColumnMappings.Add("ID", "ID");
sqlBulk.ColumnMappings.Add("STATUS", "STATUS");
sqlBulk.ColumnMappings.Add("FAN_NUM", "FAN_NUM");
sqlBulk.ColumnMappings.Add("PROFILE_NAME", "PROFILE_NAME");
sqlBulk.ColumnMappings.Add("DESTINATION_HOST", "DESTINATION_HOST");
sqlBulk.ColumnMappings.Add("USER_ID", "USER_ID");
sqlBulk.ColumnMappings.Add("USER_PASSWORD", "USER_PASSWORD");
sqlBulk.ColumnMappings.Add("PROTOCOL", "PROTOCOL");
sqlBulk.ColumnMappings.Add("PORT", "PORT");
sqlBulk.ColumnMappings.Add("PATH", "PATH");
sqlBulk.ColumnMappings.Add("CONTACT_NAME", "CONTACT_NAME");
sqlBulk.ColumnMappings.Add("CONTACT_EMAIL", "CONTACT_EMAIL");
sqlBulk.ColumnMappings.Add("CONTACT_PHONE", "CONTACT_PHONE");
sqlBulk.ColumnMappings.Add("CONTACT_ALT_PHONE", "CONTACT_ALT_PHONE");
sqlBulk.ColumnMappings.Add("CONTACT_CITY", "CONTACT_CITY");
sqlBulk.ColumnMappings.Add("CONTACT_STATE", "CONTACT_STATE");
sqlBulk.ColumnMappings.Add("CONTACT_CONTACT_TIME", "CONTACT_CONTACT_TIME");
sqlBulk.WriteToServer(dReader);
sqlBulk.Close();
excelConnection.Close();
}
private void profilesDialog_FileOk(object sender, EventArgs e)
{
}
}
}
Try this...
First:
Create first a test method which you may check if you can connect to sqlcedatabase.
private void testconnection()
{
string strConnection = ConfigurationManager.ConnectionStrings["DDP_Project.Properties.Settings.DDP_DatabaseConnectionString"].ConnectionString;
using (var conn = new SqlCeConnection(string.Format("Data Source={0};Max Database Size=4091;Max Buffer Size = 1024;Default Lock Escalation =100;", strConnection)))
{
conn.Open();
try
{
//your Stuff
}
catch (SqlCeException)
{
throw;
}
finally
{
if (conn.State == ConnectionState.Open) conn.Close();
}
}
}
Second:
Just Load your excel file Data into a Datatable and use foreach then save it on your sql ce database file..
//Something like
//oledbcon
//oledb dataadapter
//datatable
// dapt.Fill(dt);
foreach(DataRow excel in dt.Rows)
{
ceCmd.Parameters.AddWithValue("ID",excel["ID"]);
ceCmd.ExecuteNonQuery();
}
Regards
I think the problem you are seeing is that you are trying to use a SqlConnection to connect to a SQL Compact database. The .sdf is a compact database and you have to use the SqlCeConnection to connect to it. You create the connection using this but then you don't use it. Instead you pass in the connection string to the SqlBulkCopy object which implicitly creates a SqlConnection from that string. I'm assuming it is on that line where you are getting the error. If you notice the namespace of the SqlBulkCopy is System.Data.SqlClient. The reason you are seeing the error is that its trying to go through SQL Server to make the connection and cannot resolve your connection string to a SQL Server database. Unfortunately, I don't think the System.Data.SqlServerCe has the equivalent to the SqlBulkCopy. Stick to using classes in System.Data.SqlServerCe and things should work as expected. You just will have to do the processing in a more manual fashion.
According to this post, SqlBulkCopy isn't supported with SqlCe.

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