c# - Append values to a column value in database -

c# - Append values to a column value in database -

i want append big string values existing values of column value in db. column set nvarchar(max). when trying, first few parts of new string appending old value. others not appending. please suggest .

string initial_result ="xxxxxx";//reading values db column , assigning string string final_result="yyyyyyyyyy";//lengthier 1 sqlcommand cmd71 = new sqlcommand("update details set result='" + initial_result + "'+'"+finalresult+"' student_id ='11' ", con7); cmd71.executenonquery();

because using unnecessary single quotes when concatenate initial_result , finalresult values.

result='" + initial_result + "'+'"+finalresult+"' ^ ^

but more important, should utilize parameterized queries. kind of string concatenations open sql injection attacks.

also utilize using statement dispose database connections , objects.

using (sqlconnection con7 = new sqlconnection(cs)) { using (sqlcommand cmd71 = con7.createcommand()) { cmd71.commandtext = "update details set result = @result student_id ='11'"; cmd71.parameters.add("@result", sqldbtype.nvarchar).value = initial_result + finalresult; cmd71.executenonquery(); } }

c# sql asp.net sql-server