private void button1_Click(object sender, EventArgs e) { this.Hide(); Form21 form21 = new Form21(); form21.Show(); }
private void button2_Click(object sender, EventArgs e) { String connection = "Provider=OraOLEDB.Oracle;Data Source=localhost;User Id=system;Password=system;OLEDB.NET=True"; OleDbConnection obj3 = new OleDbConnection(connection); String query1 = "select isbn from book where title = '" + textBox1.Text + "'"; OleDbCommand cm4 = new OleDbCommand(query1, obj3); obj3.Open(); OleDbDataReader rd = cm4.ExecuteReader(); string isbn = string.Empty; while (rd.Read()) { isbn = rd[0].ToString(); } obj3.Close(); String query2 = "select count(*) from copy_book where isbn = '" + isbn + "'"; OleDbCommand cm5 = new OleDbCommand(query2, obj3); obj3.Open(); OleDbDataReader rd1 = cm5.ExecuteReader(); Int64 cps = 0; while (rd1.Read()) { cps = int.Parse(rd1[0].ToString()); } obj3.Close(); if (cps > 0) { MessageBox.Show("Please Delete copies of the Books First"); Form21 form21 = new Form21(); form21.Show(); } else { String query = "DELETE FROM book WHERE isbn ='" + isbn + "'"; obj3.Open(); try { OleDbCommand cm2 = new OleDbCommand(query, obj3); cm2.ExecuteNonQuery(); MessageBox.Show("Book Deleted from Database"); } catch (Exception ee) { MessageBox.Show("Error...Book not Deleted"); } obj3.Close(); } }