c# - FUNCTION not returning required value -

i have created class library generates number everytime use in other windows application , number gets updated everytime use it.

public int generate_num(string p_prm_type) {     try     {         int v_last_no = 0;         string query = @"select parm_value soc_parm_mast parm_type = '" + p_prm_type + "';";         command.commandtext = query;         oledbdatareader reader = command.executereader();         reader.read();         v_last_no = int32.parse(reader["parm_value"].tostring()) + 1;         reader.close();         command.commandtext = @"update soc_parm_mast set parm_value = parm_value+1 parm_type = " + p_prm_type + ";";         command.executenonquery();         return v_last_no;     }     catch(exception exception)     {         return 404;     } } 

i using class in other windows form application generate new no. everytime call it.but not working , returning 404.

int vtrans_no = gen_no.generate_num("tran"); 

there missing quotes on second query, p_prm_type string need put ' ' :

command.commandtext = @"update soc_parm_mast set parm_value = parm_value+1 parm_type = '" + p_prm_type + "';"