C # Access SQL Server additions and Deletions check code instances _c# Tutorial

A special implementation of access to SQL Server database and delete the operation code to check, to share with you, the specific content as follows

Using System;
Using System.Collections.Generic;
Using System.ComponentModel;
Using System.Data;
Using System.Drawing;
Using System.Linq;
Using System.Text;
Using System.Windows.Forms;
Using System.Data;

Using System.Data.SqlClient; namespace WindowsFormsApplication1 {public partial class Form1:form {public Form1 () {Initializecomp
    Onent (); }//Query private void Button1_Click (object sender, EventArgs e) {string myconn = "Server=127.0.0.1;uid=s A;pwd=123654;database=libbook; Trusted_connection=no "//define database connection parameters SqlConnection myconnection = new SqlConnection (myconn);//define a data connection instance Sqlcomm and mycommand = new SqlCommand ("SELECT * from Book borrow", MyConnection); Define a database operation instruction SqlDataAdapter selectadapter = new SqlDataAdapter ();//define a data adapter Selectadapter.selectcommand = My command;//defines a data adapter's operation instruction DataSet myDataSet = new DataSet ();//define a DataSet Myconnection.open ();//Open database connection SelectA Dapter. Selectcommand.executenonquery ()//Execute dataLibrary query Instruction Myconnection.close ()//Close database Selectadapter.fill (myDataSet);//fill DataSet DataGrid1.DataSource = Mydatase
      T.tables[0];
      Datagrid1.databind ()//To populate the data table with data in a DataSet}//Add private void button2_click (object sender, EventArgs e) { String myconn = "Server=127.0.0.1;uid=sa;pwd=123654;database=libbook;"
      Trusted_connection=no ";
      SqlConnection myconnection = new SqlConnection (myconn); String Myinsert = "INSERT into book borrow (book Number, reader number, renew number) VALUES (' + convert.tostring (textbox2.text) +" ', ' "+ conver
      T.tostring (TextBox3.Text) + "', '" +convert.toint32 (textbox4.text) + "')";
      SqlCommand mycommand = new SqlCommand (Myinsert, MyConnection);
        try//exception Handling {myconnection.open ();
        Mycommand.executenonquery ();
      Myconnection.close (); The catch (Exception ex) {MessageBox.Show (ex).
      message); }//update private void Button3_Click (object sender, EventArgs e) {string myconn = "Server=127.0.0.1;uid=sa;pwd=123654;database=libbook;
      Trusted_connection=no ";
      SqlConnection myconnection = new SqlConnection (myconn);
      String myupdate = "Update book borrow set operator = '" + TextBox2.Text + "'" + "where to borrow number =" + "'" + TextBox1.Text + "'";
      SqlCommand mycommand = new SqlCommand (myupdate, MyConnection);
        try {myconnection.open ();
        Mycommand.executenonquery ();
        Myconnection.close ();
      TextBox1.Text = ""; The catch (Exception ex) {MessageBox.Show (ex).
      message); }//delete private void Button4_Click (object sender, EventArgs e) {string myconn = "server=127.0.0.1 ; Uid=sa;pwd=123654;database=libbook;
      Trusted_connection=no ";
      SqlConnection myconnection = new SqlConnection (myconn);
      String mydelete = "Delete from book borrow where borrow number =" + TextBox1.Text;
      SqlCommand mycommand = new SqlCommand (Mydelete, MyConnection);
        try {myconnection.open (); MycomMand.
        ExecuteNonQuery ();
        Myconnection.close ();
      TextBox1.Text = ""; The catch (Exception ex) {MessageBox.Show (ex).
      message);

 }
    }
  }
}

The database is as follows;

Query success in WinForm;

When inserting, because the borrowing number is the self increment, cannot insert the value, will generate itself;

Update, foreign key conflict; The inserted book number is 000999, no this book, so error;

Insert success;

Update operator for "teacher Wang";

Delete the record of loan number 31;

The above is the entire content of this article, I hope to help you learn, but also hope that we support the cloud habitat community.