我如何使用像运营商，在一个SQLite查询参数？

本文介绍了我如何使用像运营商，在一个SQLite查询参数？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 我可以通过在LINQPad中输入这个结果来获得我想要的结果：I can get the result I expect by entering this in LINQPad:SELECT * FROM WorkTable WHERE WTName LIKE "DSD__20090410014953000%"（它显示了WTName值为DSD__20090410014953000.xml的记录）(it shows me the record which has a WTName value of DSD__20090410014953000.xml")但是试图这样做是编程方式正在尝试。我尝试：But trying to do this programmatically is proving trying. I tried:const string qry = "SELECT SiteNum FROM WorkTable WHERE WTName LIKE @wtName%";using (SQLiteConnection con = new SQLiteConnection(HHSUtils.GetDBConnection())){ con.Open(); SQLiteCommand cmd = new SQLiteCommand(qry, con); cmd.Parameters.Add(new SQLiteParameter("wtName", tableName)); siteNum = Convert.ToInt32(cmd.ExecuteScalar());} ...但是会导致应用程序崩溃，日志文件告诉我为什么：...but it causes the app to crash, and my log file tells me why:Message: From application-wide exception handler: System.Data.SQLite.SQLiteException: SQL logic error or missing databasenear "%": syntax error因此，也许它认为查询参数被命名为wtName％而不是wtName;但是用空格分隔参数和无论什么操作符（％）不起作用。So maybe it thinks the query parameter is named "wtName%" instead of "wtName"; but separating the parameter and the "whatever" opertor ("%") with a space doesn't work, either.我可以通过嵌入查询参数到字符串中，如下所示：I could go retro/kludgy by just embedding the query parameter into the string like so:const string qry = String.Format("SELECT SiteNum FROM WorkTable WHERE WTName LIKE {0}%", tableName); ...并且没有查询参数，但恐怕如果我这样做 Troy Hunt 会出现在我的房子，在栏杆关于SQL注入时，我躺在床上。...and doing without the query parameter altogether, but I'm afraid if I did that Troy Hunt would show up at my house and flail me with a bedrail while railing about SQL Injection.如何获得我的数据并同时写入安全代码？How can I get my data and simultaneously write safe code?推荐答案通配符％应添加到参数值，而不是参数名称The wildcard % should be added to the parameter value, not to the parameter nameconst string qry = "SELECT SiteNum FROM WorkTable WHERE WTName LIKE @wtName";using (SQLiteConnection con = new SQLiteConnection(HHSUtils.GetDBConnection())){ con.Open(); SQLiteCommand cmd = new SQLiteCommand(qry, con); cmd.Parameters.Add(new SQLiteParameter("@wtName", tableName + "%")); siteNum = Convert.ToInt32(cmd.ExecuteScalar());}然而，我不知道这是否重要，请使用占位符（@wtName）And, I am not sure if it matters here, but, usually, I insert the parameter name with the exact name used in the placeholder ( @wtName ) 这篇关于我如何使用像运营商，在一个SQLite查询参数？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！