I have a Windows Application written in C#, using Sqlite3 as its database. I want to update my database in Host with my Windows Application database.
You can connect to an SQLite3 database using the following code.
SQLiteConnection db = new SQLiteConnection("Data Source=/path/to/file.db;Version=3;");
db.Open();
If you want to specify additional connection parameters, ConnectionStrings.com is always a good resource. Also, you might check out this question which is similar to yours.
Related
I have a problem I need to solve, but not know how exactly. I have a WinForms application (C#) which connects to an online MySQL server - no problem there. In this application I have an option to make database backups (basically I dump this database to a local file on a computer).
I would like to locally "open" this backup on client's computer (to check some old data) - I don't want to make database restore on my server, because database must still be in use for other users. I want to make clean install of MySQL on a local computer and connect to it trough localhost (like I do for testing ), but I do not have physical access to that computer. I can send MySQL installer to my client, but how to go about automatically creating user with password and database from my dump file?
I know how to create a new database if it doesn't exist, but how to do it if it's clean install of MySQL server - no user and password yet.
string connStr = "server=localhost;user=root;port=3306;password=????;";
using (var conn = new MySqlConnection(connStr))
using (var cmd = conn.CreateCommand())
{
conn.Open();
cmd.CommandText = "CREATE DATABASE IF NOT EXISTS `hello`;";
cmd.ExecuteNonQuery();
}
Any help and direction is appreciated.
Regards!
I don't know whether I understand your problem. However,if you install a new Mysql，you can use root user through no database.
Anyway, one thing you need to know,Connect database must has user and password for mysql or sqlserver.
You may need to be more concise description of your problem.
This question already has an answer here:
SqlConnection not being able to open the connection
(1 answer)
Closed 6 years ago.
I am trying to connect to my free sql database that I opened in: www.freesqldatabase.com/account/.
When using this www.phpmyadmin.co/ admin tool I can get into the databse, add tables and all that. But i can't connect to this database from my project.
using this code:
SqlConnection sql = new SqlConnection("Server=sql7.freesqldatabase.com;Database=sql7115***;User Id=sql7115***;Password =*****;");
sql.Open();
I get an SqlException saying that "Could not find the server".
Am I missing something?
By the way i am getting those warnings
and if i click "here" i see this.
P.S:
When i ping the host with the right port (that was sent to me with the email) I get a reply, so it is probably listening.
At the moment, the service you are using only offers MySql databases (though they intend offering MS SQL Server databases in the near future.
The problem is that the SqlConnection class you are using is deliberately tailored to MS Sql Server Databases, and - as I just said - that's not what you are talking to.
You will want to find an ADO.Net solution for MySQL - something like this.
Alternatively, you might be able to use OLEDB if you have suitable drivers installed...
You can use the NuGet Package MySql.Data. To use it in your project insert following in the Package Manager Console.
Install-Package MySql.Data
After that you can use the class MySqlConnection.
Don't forget to include the reference in your class!
using MySql.Data;
using MySql.Data.MySqlClient;
You should be able to establish a connection like this:
string connectionString = "server=sql7.freesqldatabase.com;user=sql7115***;database=sql7115***;password=******;";
MySqlConnection mySqlConnection= new MySqlConnection(connectionString);
mySqlConnection.Open();
For further information you can look in the tutorial.
How can I connect my Trgovina.mdf with dataGridView?
I follow this tutorial, but it seems that program doesn't find my database.
Connection string looks like that:
string connString = #"Data Source=(LocalDB)\v11.0;AttachDbFilename=C:\Users\Klemen\documents\visual studio 2012\Projects\Trgovina\Trgovina\Trgovina.mdf;Integrated Security=True";
Everything else is the same as tutorial example.
Error string is An OLE DB Provider was not specified in the ConnectionString. An example would be, 'Provider=SQLOLEDB;'
Full code looks like this.
The tutorial you talk about in your question use an Access Database and thus uses the OleDB engine to reach and work with the database. Instead your connection string use the syntax reserved for SQLServer LocalDB.
You should change your objects to SqlConnection (instead of OleDbConnection), SqlCommand (instead of OleDbCommand) and so on...
With these changes you should be able to connect to the automatic instance of SqlServer LocalDB. The rest of the tutorial could work or not, depending on what is present in the MDF file used.
You trying to connect to database .mdf file, but you have a wrong provider.
An MDF is a Microsoft SQL Server database not a Jet Database like
Access (*.mdb). You cannot just connect to the flat file and read it.
You would need to mount the database in an instance of SQL Server.
You could install SQL Server 2005 Express
Source
Note: Just download MS SQL Server 2005 Express or later and you must use the System.Data.SqlClient instead of OLE DB to solve your problem.
I have an application with a database called voodoobase.sdf.
Using .NET Framework Data Provider for Microsoft SQL Server Compact 3.5
I can see it in Server Explorer and connect to it fine from there. The DB File is located in:
c:\Users\me\Documents\VisualStudio2010\Projects\testproj\voodoobase.sdf
The same named DB under Solution Explorer is said to reside at the same location.
c:\Users\me\Documents\VisualStudio2010\Projects\testproj\voodoobase.sdf
Assuming they are the same... why can my application which compiles successfully alwways crash with a connection error:
SqlConnection dbCon = new SqlConnection(Properties.Settings.Default.voodoobaseConnectionString);
dbCon.Open();
Throws an error on dbCon.Open() saying that could not get a connection to the SQL server. Let me know if further detail is required.
Do not use the SqlConnection class, but the SqlCeConnection class.
I'm using Linq2Entity for most of my database operations. However for database creation, table creation and initial data insertion I use plain SQL files. Therefore I need both an SqlConnection and an EntityConnection. Unfortunately the Entity Framework starts complaining that the Sql Server is not listening on the other end of the pipe.
I'm not sure what the problem is here, it could be due to user instancing. Clearing the pool of the SqlConnection or disposing the connection instance does not help.
The connection string I'm using is the following:
"Data Source=.\SQLEXPRESS; Initial Catalog=dbname; Integrated Security=SSPI;"
update:
I have tried to use the EntityConnection for database maintenance purposes but I'm running into troubles. I can't use the EntityConnection to create databases and drop databases. The following syntax is unsupported for an EntityConnection but works fine for an SqlConnection to ms SQL express.
CREATE DATABASE silverfit ON ( NAME = silverfit, FILENAME = 'c:\silverfit\silverfit.mdf' );
Also for some reason the EntityConnection does not allow me to change databases which is necessary to drop a database. I'm afraid I still need the SqlConnection to create the database and tables..
Is there a way for SqlConnections and EntityConnections to coexist for local ms SQL express databases?
Thanks,
Wouter
Have you tried creating a SqlConnection which you then pass to the constructor for your EntityConnection? One of the overloads for EntityConnection takes a MetadataWorkspace and a DbConnection (from which SqlConnection derives.) The slight drawback of this is that you must create your MetadataWorkspace manually, which gathers up the .csdl, .ssdl, and .msl files that define your workspace. However, in the long run, you should be able to share a single connection for both executing DML queries, and using Entity Framework.
I don't agree that you need a plain SQL connection and Entity connection for this task, at least as you've described it. You can execute SQL using the Entity connection. Look at EntityConnection.CreateDbCommand. Naturally, there's a danger here that you are doing DB-server-specific things on a non-DB-server-specific instance like a EntityConnection. But it probably beats having a separate connection, in this case.
Did you try to use the EntityConnection.StoreConnection to retrieve the SqlConnection and execute commands with it ?
If you're trying attaching your database file to SQL Server Express at run time, which it seems as if you are, then only one connection can be open on it at once. This is a problem for other things, not just what you're trying to accomplish. Say, for instance, you connect to 'c:\silverfit\silverfit.mdf' through the server explorer in VS and try to open one of the tables in the db. After you open the table, try running your application. It will bomb.
However, if you open up SQL Management Studio Express (you can download it here), and then attach the database to the SQL Server, the problems you are experiencing should go away. At that point you should be able to open multiple connections to your database, via SQLConnection or EntityConnection.
Attaching your database at run time to the SQL Server express engine really only works well for demoing purposes, or proof of concepts.
Is ADO.NET holding a connection open to the database through connection pooling? Try adding Pooling=False to the connection string, as this may allow the database to be closed before you drop it.