c# - update the datetime value of a table MS SQL from ASP.NET code -

i've table "user_info" fields , datatypes.

user_id || user_reg_date [datetime] null default (getdate()) || user_next_visit_date [datetime] null

here user_reg_date default value, format :: 2015-06-02 12:17:12.307

for field, user_next_visit_date i've update asp.net code, same format user_reg_date.

string querystring = "update user_info set user_next_visit_date = ???     user_id ='" + user_id + "'"; 

how set value of user_next_visit_date [datetime] current date time in same format user_reg_date. face problem datetime values inserting asp.net database.

a datetime has no format. updating easy cake parametrized queries:

sqlcommand query = new sqlcommand(); query.connection = ...  // parameters start @ string querystring = "update user_info set user_next_visit_date = @somedatevar user_id=@userid"; query.commandtext = querystring;  // date parameter sqlparameter dtpar = new sqlparameter("@somedatevar", sqldbtype.datetime, 0); dtpar.value = datetime.now; // or datetime have query.parameters.add(dtpar);  // id parameter sqlparameter idpar = new sqlparameter("@userid", sqldbtype.int, 0); idpar.value = user_id; query.parameters.add(idpar);  // execute query.executenonquery(); 

this has side effect sql injections no longer possible.

in fact, use add-a-parameter part recommend shortcuts make them oneliners.