I need to make a copy of an azure database but I don't have access to any management tools, only a connection string.
I know that to use the CREATE DATABASE x AS COPY OF y command I need to be in the master database but I don't know how to tell Azure to run my command from there. For example, I have this code:
var commandText = "CREATE DATABASE foobar AS COPY OF " + database;
var connectionString = <my_connection_string>;
using (var conn = new SqlConnection(connectionString))
{
using (var cmd = new SqlCommand(commandText, conn))
{
cmd.CommandType = CommandType.Text;
conn.Open();
cmd.ExecuteNonQuery();
}
}
which fails with error "User must be in the master database" - as I expected.
However my connection string is not valid for the master database, so how do I execute this command from the master database? If I was in SQL Management Studio I would just do:
use master
CREATE DATABASE x AS COPY OF y
Is there any way of emulating that in my code?
Change your connection string to access the master database instead of your regular one. It's as simple as that and the only solution.
Related
I am trying to create to a local database via a mdf file, like so:
scon = new SqlConnection(#"Data Source=(LocalDB)\MSSQLLocalDB;AttachDBFilename=|DataDirectory|\articles.mdf; Integrated Security=True");
scon.Open();
scmd = new SqlCommand("Insert INTO articles(url) VALUES(#url)");
scmd.Parameters.AddWithValue("#url", "http://google.com");
scmd.ExecuteNonQuery();
MY mdf file is in the root folder, and in the debug folder too. When I run the following code I get an error saying the following:
I can't use the full connection path because it's a long url with spaces, here is my file structure:
My database exists:
How can I fix this so I can connect to my database?
Pass the connection object to the SqlCommand constructor
scmd = new SqlCommand("Insert INTO articles(url) VALUES(#url)", scon);
The connectionstring is fine, the error message informs you that it is not possible to execute a command if the database is not known. The SqlConnection contains this information and you need to pass it to your command.
Another possibility is through the
scmd.Connection = scon;
but, personally, I prefer to pass that info in the constructor.
Final but really important note:
SqlConnection and SqlCommand are disposable objects. You should always dispose these kind of objects. The using statement is the correct method
using(scon = new SqlConnection(....))
using(scmd = new SqlCommand("Insert INTO articles(url) VALUES(#url)",scon))
{
scon.Open();
scmd.Parameters.AddWithValue("#url", "http://google.com");
scmd.ExecuteNonQuery();
}
The Problem With Your Code Is That You Have A Command and a Connection But There Is Nothing To Till The Command To Use This Connection Object ... You Can Use The SqlCommand Constructor To Do That
scmd = new SqlCommand("Insert INTO articles(url) VALUES(#url)",scon)
Or Use The Connection Property Of The SqlCommand Class Like This
scmd.Connection = scon
Consider Adding Using To Your SQL Connection ... Or Else You Will Have To Manually Close The Connection By Calling scon.Close();
if You Didn't Do either Of Those You Will Run Into An Exception If Your Tried To Open The Connection Again While It's Already Open
I just added a new "local database" in my project using visual studio. Now I added the "New Data Source".
What I want to know is how you can do sql queries to the DB. I know how this is done in PHP but cant find good information about how to do this in C#. All I find is tutorials on how to drag detail or gridviews into the form.
I have one database called 'words' with three tables. I want to be able to do update queries to a row in each of these tables. something like this:
UPDATE easy SET words='blahblahblah' WHERE id=1;
How do you do this?
I am going to use SQL Server as example.
First you need to find out the connection string which should be similar to
_connectionString = "Data Source=(localdb)\\v11.0; Initial Catalog=words;Integrated Security=true;"
and then you do
using (SqlConnection connection = new SqlConnection(_connectionString))
{
connection.Open();
using (SqlCommand cmd = new SqlCommand("UPDATE easy SET words='blahblahblah' WHERE id=1;", connection))
{
cmd.ExecuteNonQuery();
}
}
I have a T-SQL script to create a Database. I need to create this database runtime. When the application is Running.
What Connection String do I use?
How do I connect to the server and Create the Database? I am connecting to the server as a Network user. I am not using User "sa" I have a user "DBCreator"
My application is in C#.
I have this Script in T-SQL:
USE [master]
GO
CREATE DATABASE [XYZ]
-- Table Creation Code etc.
You can have two connection strings. One for master database to issue the CREATE DATABASE ... statement and another one for database created.
// You can use replace windows authentication with any user credentials who has proper permissions.
using (SqlConnection connection = new SqlConnection(#"server=(local);database=master;Integrated Security=SSPI"))
{
connection.Open();
using (SqlCommand command = connection.CreateCommand())
{
command.CommandText = "CREATE DATABASE [XYZ]";
command.ExecuteNonQuery();
}
}
// Quering the XYZ database created
using (SqlConnection connection = new SqlConnection(#"server=(local);database=XYZ;Integrated Security=SSPI"))
{
connection.Open();
using (SqlCommand command = connection.CreateCommand())
{
command.CommandText = "select * from sys.objects";
...
}
}
You can use the SMO objects to do that. I don't think i should explain what is already explained in details in a very good tutorial here
Definitely use SMO its intended to do everything that SSMS can do, and more! it actually has a command called Database.Create(), follow this MSDN page
I am trying to create an application which will synchronize its database with another software's database..
Problems are:
How will the database will synchronize with external database after I have created the installer and installed..i.e. how will it take the connection string.
I am looking for a solution which will provide a button to select the required database and based on the selection automatically generate the connection string.
Is it possible to run SQL create queries on external database while installation after the database is selected via browse button?
You have an option to create a Connection Settings form, which will help user to construct the connection string.
Yes, it's possible. It looks something like this:
using (var sqlConnection = new SqlConnection(#"Data Source=myServerAddress;User Id=myUsername;Password=myPassword;"))
{
sqlConnection.Open();
string query = "CREATE DATABASE...";
using (var sqlCommand = new SqlCommand())
{
sqlCommand.Connection = sqlConnection;
sqlCommand.CommandText = query;
sqlCommand.ExecuteNonQuery();
}
}
If it won't work, try to set Initial Catalog to master:
#"Data Source=myServerAddress;Initial Catalog=master;User Id=myUsername;Password=myPassword;"
after connecting to database in C#
string MyConString2 = "SERVER=localhost;" + "user id=mytest;" + "DATABASE=clusters;" + "PASSWORD=mypass;";
I have an algorithm which I need to after each run of algorithm that will fill the database, drop the database "clusters" of mysql manually and again connect to the empty database and run it again,gaining new data in tables
I want to make it automatically how can I drop or empty my database if exists in C# and then run my algorithm?
Here is example code that works and I think this is what you are talking about, if not, feel free to correct me.
using (var connection = new MySqlConnection("server=localhost;user=root;password="))
{
connection.Open();
var command = connection.CreateCommand();
command.CommandText = "drop schema if exists clusters";
command.ExecuteNonQuery();
command = connection.CreateCommand();
command.CommandText = "create schema clusters";
command.ExecuteNonQuery();
}
Prepare sql query for clearing your DB and test it in f.e. MySQL workbench. Following this, just execute it as you would execute regular query against DB in C#. One way is to clear all the tables in your database by using TRUNCATE statement and the second way is to DROP DATABASE and recreate it.