Delete data from sql server(C#)

Member 10484848

hi friends How i can delete data from data base(sql server) in C#?????

Ade Ruyani Z

this is simple script to delete using webform asp.net C# here is my code: 1. adding connection in Web.config Web.config ==========

2. in default.aspx default.aspx ============ added namespace: using System.Data.SqlClient; using System.Configuration;

protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
string connProvider = ConfigurationManager.ConnectionStrings["myConnection"].ToString();
using (SqlConnection cnn = new SqlConnection(connProvider))
{
cnn.Open();
string userid = "1";
string query = "Delete Users Where UserID = '" + userid + "'";
using (SqlCommand cmd = new SqlCommand(query, cnn))
{
cmd.ExecuteNonQuery();
}
}
}
}

hope this help. (Update)= this code not recommended for develop, you can try it for learn and you can improve your code. regard, Ade Ruyani

OriginalGriff

Reason for my downvote: Do not concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead. Even in a simple example like this, it takes hardly any extra work to do it properly!

Never underestimate the power of stupid things in large numbers --- Serious Sam

Ade Ruyani Z

Thank you sam, this is just a simple code, whether they can improve they're code using store procedure or else.

Simon_Whale

int RowsAffected = 0;
using(SqlConnection cn = new SqlConnection(ConnectionStringHere))
{
cn.Open();

using(SqlCommand cmd = new SqlCommand())
{
cmd.Connection = cn;
cmd.CommandType = CommandType.Text;

 //This shows how to delete with a simple where clause
 cmd.CommandText = "Delete from tablename where id = @id"; 
 cmd.Parameters.AddWithValue("@id",id);
 RowsAffected = cmd.ExecuteNonQuery();

}
}

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Lost User

Ade.Ruyani.Z wrote:

this is just a simple code

It is still a bad example, because it leads to careless coding.

Veni, vidi, abiit domum

Rahul Rajat Singh

You can use ado.net: A Beginner's Tutorial for Understanding ADO.NET[^] Or any ORM like entity framework for the same: An Introduction to Entity Framework for Absolute Beginners[^]

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