2023年6月21日发(作者：)
带参数的sql语句using System;using c;using ent;using ;using ;using ;namespace 带参数的sql语句{class Program{static void Main(string[] args){string constr = “Server=localhost;Database=user;user=root;password=liuyang;”;while (true){ine(“请输⼊名称：”);string u = ne();ine(“请输⼊密码：”);string p = ne();using (SqlConnection conn = new SqlConnection(constr)){ //带参数的sql语句 @后代表参数名 string sql = "select id from users where username=@username and password=@password"; using (SqlCommand cmd = new SqlCommand(sql, conn)) { (); //声明变量，与sql语句中的参数绑定 //SqlParameter username = new SqlParameter("@username", r, 50) { Value = u }; //SqlParameter password = new SqlParameter("@password", r, 50) { Value = p }; //将变量添加到SqlCommand变量中 //(username); //(password); SqlParameter[] sq = new SqlParameter[] { new SqlParameter("@username", r, 50) { Value = u }, new SqlParameter("@password", r, 50) { Value = p } }; ge(sq); if (eScalar() != null) { //查询⼀个数据，使⽤eScalar() int id = (int)eScalar(); ine(id); } } } } }}}
2023年6月21日发(作者：)
带参数的sql语句using System;using c;using ent;using ;using ;using ;namespace 带参数的sql语句{class Program{static void Main(string[] args){string constr = “Server=localhost;Database=user;user=root;password=liuyang;”;while (true){ine(“请输⼊名称：”);string u = ne();ine(“请输⼊密码：”);string p = ne();using (SqlConnection conn = new SqlConnection(constr)){ //带参数的sql语句 @后代表参数名 string sql = "select id from users where username=@username and password=@password"; using (SqlCommand cmd = new SqlCommand(sql, conn)) { (); //声明变量，与sql语句中的参数绑定 //SqlParameter username = new SqlParameter("@username", r, 50) { Value = u }; //SqlParameter password = new SqlParameter("@password", r, 50) { Value = p }; //将变量添加到SqlCommand变量中 //(username); //(password); SqlParameter[] sq = new SqlParameter[] { new SqlParameter("@username", r, 50) { Value = u }, new SqlParameter("@password", r, 50) { Value = p } }; ge(sq); if (eScalar() != null) { //查询⼀个数据，使⽤eScalar() int id = (int)eScalar(); ine(id); } } } } }}}
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