I have a problem with connecting to the database.
private static readonly string s_connectionString = "Server=db.inu.hu; Database=patientRegistry;UID=****; Password=****; Port=3306; Trusted_Connection=true";
That's my connection string and with this I can't open the connection.
using (SQLiteConnection conn = new SQLiteConnection(s_connectionString))
{
conn.Open();
}
I thought the problem might be that I have a table in the database and need to add that to the connection string.
Are you trying to connect to MySQL or SQLite? You are referencing a SQLiteConnection object, but I think you need to be using a MySqlConnection connection object instead.
Related
So, I want to create a SQL database in Microsoft SQL Management Studio and connect it to Microsoft Visual Studio. I linked the database to Visual Studio and it worked. Now, I want to open that connection to test it with a button on a windows form application. Every time I try, it says "invalid pointer" but the database name is correct. I don't know what is wrong.
I still get the invalid pointer error...My instance name is DESKTOP-BJSAO6B but it doesnt seem to work...
You need provide a proper connection string like
string connectionString =
"data source=.\SQLEXPRESS;initial catalog=student;integrated security=True;";
using (SqlConnection connection =
new SqlConnection(connectionString))
{
connection.Open();
MessageBox.Show("You are connected");
}
where SQLEXPRESS - name your MSSQL instance ( may be different). More you can see here
For Ex:
string connectionString = "Data Source=Server-Name; Initial Catalog= Database-Name;Integrated Security=True"; //If you are using a local Database.
SqlConnection conn = new SqlConnection(connectionString);
conn.Open();
MessageBox.Show("You are connected");
So I'm following this tutorial: http://support.microsoft.com/kb/314145/
and I get an unexpected error: A first chance exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll
My class looks like this:
class Database
{
public Database()
{
string connectionString = "Password=pass;User ID=userid;Initial Catalog=soksko;Data Source=(local)";
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.Open();
Console.WriteLine("ServerVersion: {0}", connection.ServerVersion);
Console.WriteLine("State: {0}", connection.State);
}
Console.WriteLine("Database: OK");
}
}
I googled, but I couldnt find anything valuable. I am using MySQL database, it is on the same computer and I am using VS 2013. I successfully added my database to Server Explorer with the same connection information that I use above, but I get exception, when I try to open the connection.
See this link for how a MySQL connection string should look:
ASP.NET use SqlConnection Connect Mysql
See this link for an explanation of the oft mis-used Data Source=(local):
http://blogs.msdn.com/b/sql_protocols/archive/2008/09/19/understanding-data-source-local-in-sql-server-connection-strings.aspx
hint you're not using SQL-Server so it won't work for you
SqlConnection is for MS SQL Server. For MySql you need to use a MySqlConnection class provided by the MySQL connector (http://dev.mysql.com/doc/connector-net/en/index.html)
using MySql.Data.MySqlClient;
using(MySqlConnection myConnection = new MySqlConnection(myConnectionString))
{
myConnection.Open();
// execute queries, etc
}
The tutorial you're using is for Sql Server, not MySQL.
I want to know how to update a database installed on two computers. I want to update only a single database. Whether I work on 1st computer or 2nd computer I want to update the database once. How can I do this?
This is my database connect method:
public static SqlConnection connect() {
String conct = #"Data Source=.\SQLEXPRESS;AttachDbFilename=E:\3000Apliance\3000Apliance\300Apliance.mdf;Integrated Security=True;User Instance=True";
SqlConnection con = new SqlConnection(conct);
con.Open();
return con;
}
Use one Computer as Server keep your database there. on other computer use sqlmanagement and connect to server computer via Ip/name 192.0.0.0/name and create a path to database.
this way you can use more then 2 computers to update database at a time. you can connect computers by peer to peer or use a switch to connect multiple computers.
your new connection string should look like this:
Data
Source = . \ SQLEXPRESS; AttachDbFilename=192.0.0.0\name\3000Apliance\3000Apliance\300Apliance.mdf; Integrated Security=True;User Instance=True";
SqlConnection con = new SqlConnection(conct);
Looks like SQLite database connection doesn't actually try to open database connection when I call Open() function. Here's a simple test:
var factory = DbProviderFactories.GetFactory("System.Data.SQLite");
connection = factory.CreateConnection();
connection.ConnectionString = "data source=NonExistentDB.db3";
conn.Open();
The above code does not generate any kind of exception. Moreover, the connection state is Open after this. Is there a way to do "Test Connection" that would physically establish a connection with the database?
Change to
connection.ConnectionString = "data source=NonExistentDB.db3;FailIfMissing=True"
Without the last argument, it will simply create a new database if the file is not found.
Newb questions incoming.
I'm running MySQL locally and I am having a really hard time connecting to it with C#.
Here's the code I'm using, much of the stuff I've tried out is commented out:
using System;
using System.Collections.Generic;
//using System.Data.Common.DbConnection;
using System.Threading;
using System.Data.OleDb;
using System.Data.SqlClient;
using System.Threading;
namespace mvpde
{
class Program
{
class DataReader_SQL
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main(string[] args)
{
//
// TODO: Add code to start application here
//
try
{
OleDbConnection con = new OleDbConnection(#"Provider=sqloledb;Data Source=127.0.0.1:3306;database=database_name;User id=id;Password=password;");
con.Open();
//Thread.Sleep(9999);
//SqlConnectionStringBuilder builder = new SqlConnectionStringBuilder();
//builder.DataSource = "localhost";
//builder.UserID = "hello";
//builder.Password = "password";
//builder.InitialCatalog = "db_123";
//SqlConnection thisConnection = new SqlConnection(builder.ToString());
//thisConnection.Open();
//SqlCommand thisCommand = thisConnection.CreateCommand();
//thisCommand.CommandText = "SELECT CustomerID, CompanyName FROM Customers";
//SqlDataReader thisReader = thisCommand.ExecuteReader();
//while (thisReader.Read())
//{
// Console.WriteLine("\t{0}\t{1}", thisReader["CustomerID"], thisReader["CompanyName"]);
//}
//thisReader.Close();
//thisConnection.Close();
}
catch (SqlException e)
{
Console.WriteLine(e.Message);
Thread.Sleep(9999999);
}
}
}
}
}
I've copied it nearly verbatim and tried to make it work from this site.
I have installed the MySQL on Windows 7 - I have created the user and the database I'm trying to access and I can do all this just fine using MySQL's own MySQL Workbench 5.2 CE software. I seem to have no clue what I'm doing using C# to connect to it.
All I want is to connect to it and send it a simple query like "USE DATABASE somedb" and then "SELECT TABLE sometable".
Errors I'm getting:
At first (when I used WAMP, before installing the MySQL package from mysql website) I would be able to connect once and see a login error; after that, it's as if the connection wasn't closed properly and I'd be unable to get even that far)
Now that I'm trying to connect to a MySQL instance that is created by MySQL's own software (or by running mysqld.exe) all I ever get is timeout problems\server not found\inaccessible.
Questions:
Am I using the wrong class?
What's the deal with "Provider="? where is the list of all the available variables for that part of the string? What does it mean? Why are the names involved so cryptic?
I imagined connecting to a locally-running MySQL server should be a breeze, but I've no idea what I'm doing.
Thank you.
You should use the MySql/Connector for DotNet.
Download it at this address then change your connection string accordingly.
For example "Server=127.0.0.1;Database=database_name;Uid=id;Pwd=password;Port=3306"
For other options, specific for MySQL, look at www.connectionstrings.com
have you had a look at http://www.connectionstrings.com/mysql ?
You can't use a SQL Connection object. You need a MySQL Connection object which is available in this library.http://www.connectionstrings.com/mysql
Download the MySQL Connection Library and use one of their connection strings provided on the site.
using MySql.Data.MySqlClient;
MySqlConnection myConnection = new MySqlConnection;();
myConnection.ConnectionString = myConnectionString;
myConnection.Open();
//execute queries, etc
myConnection.Close();
Then use the connection object to initalise the connection string and connect to MySQL