add column in database using C# code

praveen maurya

hello there

i want to create a column in an existing table of my database using C# i mean in my window form 1 textbox and one button is there
i enter some text and clik on the button
then i creates a column named as i write in textbox
my database is sql server database .mdf file

help me out please

6 Replies

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Raja T10y ago
Hello Praveen, Try like

string constr = ConfigurationSettings.AppSettings["ConnectionString"].ToString();

private void button1_Click(object sender, EventArgs e)
{
string query = "alter table [FirstTable] add " + textBox1.Text+" int NULL ," +textBox2.Text+" varchar(50) NULL ";
SqlConnection con = new SqlConnection(constr);
SqlCommand cmd = new SqlCommand(query, con);
con.Open();
int i = Convert.ToInt32(cmd.ExecuteNonQuery());
con.Close();
}
shivkumar patil10y ago
hello there

i want to create a column in an existing table of my database using C# i mean in my window form 2 textbox and one button is there
i enter some text and click on the button
then i creates a 2 column named as i write in 2 textbox
my database is sql server database .mdf file

help me out please
Satyapriya Nayak14y ago
Hi Praveen,

string str = "alter table [dbo].new add" + textBox1.Text.ToString() + "varchar(50) null";

Change it to

str = "ALTER TABLE [dbo].[new] ADD " + TextBox1.Text.ToString() + " Varchar(50) NULL ";

Note

1.put space between add and " .
2.put space between " and varchar(50).
3.change [dbo].new to [dbo].[new].

Thanks
praveen maurya14y ago
hello kunal

i am using the following code

using System.Data.SqlClient;
System.Data.SqlClient.SqlConnection cn;

{ (button click event)

cn = new System.Data.SqlClient.SqlConnection();
cn.ConnectionString = "Data Source=.\\SQLEXPRESS;AttachDbFilename=|DataDirectory|\\testing.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True";
cn.Open();
string str = "alter table [dbo].new add" + textBox1.Text.ToString() + "varchar(50) null";
SqlCommand cmd = new SqlCommand(str, cn);
cmd.ExecuteNonQuery();
cn.Close();
}

and it shows error that is
Incorrect syntax near 'addexfvarchar'

where exf is the name i am entering in my textbox for new table
Satyapriya Nayak14y ago
Hi Praveen,

Kunal code is working fine

using System.Data.SqlClient;
string connStr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
SqlCommand com;
string str;

protected void Button1_Click(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection(connStr);
con.Open();
str = "ALTER TABLE [dbo].[Test] ADD " + TextBox1.Text.ToString() + " Varchar(50) NULL ";
com = new SqlCommand(str,con);
com.ExecuteNonQuery();
con.Close();
}

Please accept kunal's answer

Thanks
Kunal Vaishya14y ago
Dear praveen,

Set Command String in SqlCommand and Execute Command

ALTER TABLE [dbo].[DatabaseName] ADD ColumnName Varchar(50) NULL

ALTER TABLE [dbo].[Nothwind] ADD "+ textbox1.Text.ToString() +" Varchar(50) NULL

just do it column will created