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();
}
}
Related
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 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.
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;"
I have installed SQLite and am using the wrapper from: http://sqlite.phxsoftware.com/
I have created my database and table in the server explorer in VS2010 but when I create the connection, I don't understand what to do from there and how to get it to work.
Can someone provide code examples on how to connect to a db, get a table, insert data into the table and select data from a table and output it.
I would really appreciate it.
Thanks
Server Explorer is overkill, SQLite is meant to be simple and light. Just use plain code as follows.
SQLiteConnection connection = new SQLiteConnection("Data source=PATH_TO_YOUR_DB;Version=3");
connection.Open();
SQLiteCommand command = connection.CreateCommand();
command.CommandText = "insert into something values (1,2,3)";
command.ExecuteNonQuery();
connection.Close();
Hope it helps.
OK here is what I did (assuming that you have that s**t installed):
1.-right click on server explorer
2.-then click on add conection
3.-on data source click Change then select sqlite
4.-fill out da details
5.-you are done... you can now add datasets....
How can I get a DataSet with all the data from a SQL Express server using C#?
Thanks
edit: To clarify, I do want all the data from every table. The reason for this, is that it is a relatively small database. Previously I'd been storing all three tables in an XML file using DataSet's abilities. However, I want to migrate it to a database.
You can use the GetSchema method to get all the tables in the database and then use a data adapter to fill a dataset. Something like this (I don't know if it compiles, I just paste some code and change it a bit):
DbProviderFactory factory = DbProviderFactories.GetFactory("System.Data.SqlClient");
DataTable tables = null;
DataSet database = new DataSet();
using (DbConnection connection = factory.CreateConnection())
{
connection.ConnectionString = "Data Source=(local);Initial Catalog=Northwind;Integrated Security=True";
string[] restrictions = new string[4];
// Catalog
restrictions[0] = "Northwind";
// Owner
restrictions[1] = "dbo";
// Table - We want all, so null
restrictions[2] = null;
// Table Type - Only tables and not views
restrictions[3] = "BASE TABLE";
connection.Open();
// Here is my list of tables
tables = connection.GetSchema("Tables", restrictions);
// fill the dataset with the table data
foreach (DataRow table in tables.Rows)
{
string tableName = table["TABLE_NAME"].ToString();
DbDataAdapter adapter = factory.CreateDataAdapter();
DbCommand command = factory.CreateCommand();
command.Connection = connection;
command.CommandType = CommandType.Text;
command.CommandText = "select * from [" + tableName + "]";
adapter.SelectCommand = command;
adapter.Fill(database, tableName);
}
}
EDIT:
Now I refactored it a bit and now it's working as it should. The use of DbConnection and DbProviderFactories is for database engine abstraction, I recommend using it so you can change the database engine changing this line and the connection string:
DbProviderFactory factory = DbProviderFactories.GetFactory("System.Data.OracleClient");
The GetSchema method will retrive all tables from your database to a DataTable and then we get all the data from each table to the DataSet using the DataAdapter.
I think you need to narrow down the question somewhat... All the data? You mean, all the data in every table in every database? Well, the only answer to that is, a lot of code.
To connect to and talk to a SQL Server Express database engine, use the classes in the System.Data.SqlClient namespace, namely:
SqlConnection: Connect to the database
SqlCommand: Talk to the database
SqlDataReader: Iterate over data retrieved from the database
You can check the MSDN pages for all of these classes by clicking on the links above.
Here are some overview-links with more information:
CodeProject: Beginners guide to accessing SQL Server through C#
DevHood: Accessing SQL Server Data in C# with ADO.NET
Note that by and large, you use a SQL Server Express database engine the same way as the full SQL Server product, the difference is more in the tools you get with it, and some limitations in the express engine. Other than that you can just use the classes and language that you would use for a normal SQL Server database engine installation.
If this post didn't answer your question, please elaborate, and you have a higher chance of getting the answer you seek.
This can be done by using dataAdapter class.