Random display database record

xiaoxiao2021-03-06  130

Author: Meng will come from: [it] would be a wonderful world Meng Date: 2003 at 12:00:00 on April 13

The SYSTEM namespace has a Random class that generates random number. This article introduces this Random class to randomize database records. The Random class has a heavy-load method called next, which can generate random numbers, which allows two parameters to generate random numbers between the two numbers. For example: random r = new random (); random.next (1,100); will be random number between 1-100. To randomize database records, you need to know the maximum number of records and minimum records of the database. int RecNo = 0, MaxRecNo, MinRecNo; Random R = new Random (); SqlDataReader DR; SqlConnection CN = newSqlConnection ( "Server = Mengxianhui; Database = Northwind; uid = sa"); CN.Open (); SqlCommand Cmd = new Sqlcommand ("SELECTID) AS MAXPRODID, Min (Productid) AS MinProdiDID, CN); DR = cmd.executeReader (); Dr.Read (); maxRecno = (int) DR [" MAXPRODID "]; MinRecno = (int) DR ["minprodid"]; recno = r.next (minRecno, maxRecno); then get randomly logged. CMD = New SQLCOMMAND ("Select * from products where product); DR = cmd.executeReader (); Dr.Read (); response.write (" Today's product name: " DR [" ProductID "] " - " DR [" ProductName "] " ""; cn.close (); full code as follows:

<% @ Page language = "c #" debug = "true"%>

<% @ Import namespace = "system.data.sqlclient"%>

<% @ Import namespace = "system.data"%>

Random Display Database Record </ Title></p> <p></ hEAD></p> <p><body></p> <p><script runat = "server"></p> <p>Void Page_Load (Object Sender, Eventargs E)</p> <p>{</p> <p>INT Recno = 0, MaxRecno, MinRecno;</p> <p>Random r = new random ();</p> <p>SqlDataReader DR;</p> <p>// **** Connect to the database</p> <p>SqlConnection CN = New SqlConnection ("Server = mengxianhui; database = northwind; uid = sa"); cn.open ();</p> <p>// **** Find the largest and smallest ID number</p> <p>Sqlcommand cmd = new sqlcommand ("SELECT MAX (ProductID) AS MaxProdid, Min (Productid) AS MinProdid from Products, CN);</p> <p>DR = cmd.executeReader ();</p> <p>Dr.read ();</p> <p>MaxRecno = (int) DR ["MAXPRODID"];</p> <p>MinRecno = (int) DR ["minprodid"];</p> <p>Dr.close ();</p> <p>// **** Create a random number</p> <p>Recno = R. Next (MinRecno, MaxRecno);</p> <p>// **** Display random record information.</p> <p>CMD = New Sqlcommand ("SELECT * from Products Where ProductId =" Recno, CN);</p> <p>DR = cmd.executeReader ();</p> <p>Dr.read ();</p> <p>Response.write ("Today's Product Name: <B>" " " " " "" ProductName "] " </ b> ");</p> <p>Dr.close ();</p> <p>Cn.close ();</p> <p>}</p> <p></ script></p> <p></ body></p> <p></ html></p></div><div class="text-center mt-3 text-grey"> 转载请注明原文地址:https://www.9cbs.com/read-127050.html</div><div class="plugin d-flex justify-content-center mt-3"></div><hr><div class="row"><div class="col-lg-12 text-muted mt-2"><i class="icon-tags mr-2"></i><span class="badge border border-secondary mr-2"><h2 class="h6 mb-0 small"><a class="text-secondary" href="tag-2.html">9cbs</a></h2></span></div></div></div></div><div class="card card-postlist border-white shadow"><div class="card-body"><div class="card-title"><div class="d-flex justify-content-between"><div><b>New Post</b>(<span class="posts">0</span>) </div><div></div></div></div><ul class="postlist list-unstyled"> </ul></div></div><div class="d-none threadlist"><input type="checkbox" name="modtid" value="127050" checked /></div></div></div></div></div><footer class="text-muted small bg-dark py-4 mt-3" id="footer"><div class="container"><div class="row"><div class="col">CopyRight © 2020 All Rights Reserved </div><div class="col text-right">Processed: <b>0.028</b>, SQL: <b>9</b></div></div></div></footer><script src="./lang/en-us/lang.js?2.2.0"></script><script src="view/js/jquery.min.js?2.2.0"></script><script src="view/js/popper.min.js?2.2.0"></script><script src="view/js/bootstrap.min.js?2.2.0"></script><script src="view/js/xiuno.js?2.2.0"></script><script src="view/js/bootstrap-plugin.js?2.2.0"></script><script src="view/js/async.min.js?2.2.0"></script><script src="view/js/form.js?2.2.0"></script><script> var debug = DEBUG = 0; var url_rewrite_on = 1; var url_path = './'; var forumarr = {"1":"Tech"}; var fid = 1; var uid = 0; var gid = 0; xn.options.water_image_url = 'view/img/water-small.png'; </script><script src="view/js/wellcms.js?2.2.0"></script><a class="scroll-to-top rounded" href="javascript:void(0);"><i class="icon-angle-up"></i></a><a class="scroll-to-bottom rounded" href="javascript:void(0);" style="display: inline;"><i class="icon-angle-down"></i></a></body></html><script> var forum_url = 'list-1.html'; var safe_token = 'MCNUbzMVjlLSjc6YTC_2BLqE6mWgz4VDfxi0Q0q0P9FIj86t25o_2BA2dgnBTOdRNGsti4mXSi6RbC7IJwGyW9nSRg_3D_3D'; var body = $('body'); body.on('submit', '#form', function() { var jthis = $(this); var jsubmit = jthis.find('#submit'); jthis.reset(); jsubmit.button('loading'); var postdata = jthis.serializeObject(); $.xpost(jthis.attr('action'), postdata, function(code, message) { if(code == 0) { location.reload(); } else { $.alert(message); jsubmit.button('reset'); } }); return false; }); function resize_image() { var jmessagelist = $('div.message'); var first_width = jmessagelist.width(); jmessagelist.each(function() { var jdiv = $(this); var maxwidth = jdiv.attr('isfirst') ? first_width : jdiv.width(); var jmessage_width = Math.min(jdiv.width(), maxwidth); jdiv.find('img, embed, iframe, video').each(function() { var jimg = $(this); var img_width = this.org_width; var img_height = this.org_height; if(!img_width) { var img_width = jimg.attr('width'); var img_height = jimg.attr('height'); this.org_width = img_width; this.org_height = img_height; } if(img_width > jmessage_width) { if(this.tagName == 'IMG') { jimg.width(jmessage_width); jimg.css('height', 'auto'); jimg.css('cursor', 'pointer'); jimg.on('click', function() { }); } else { jimg.width(jmessage_width); var height = (img_height / img_width) * jimg.width(); jimg.height(height); } } }); }); } function resize_table() { $('div.message').each(function() { var jdiv = $(this); jdiv.find('table').addClass('table').wrap('<div class="table-responsive"></div>'); }); } $(function() { resize_image(); resize_table(); $(window).on('resize', resize_image); }); var jmessage = $('#message'); jmessage.on('focus', function() {if(jmessage.t) { clearTimeout(jmessage.t); jmessage.t = null; } jmessage.css('height', '6rem'); }); jmessage.on('blur', function() {jmessage.t = setTimeout(function() { jmessage.css('height', '2.5rem');}, 1000); }); $('#nav li[data-active="fid-1"]').addClass('active'); </script>