Question

I am attempting to dynamically update a set of database tables. I have two variables;
table_name & field_name. These are populated by a foreach loop, that loops through a DataTable. Everytime we hit a new row in the DataTable the names change respectively. Within this loop I create a new Oracle Connection and attempt to write an update with the current table_name/field_name. But Oracle keeps giving me an error on my ExcecuteNonQuery command.
Any help is greatly appreciated!!

EDIT: I have reformatted to include parameters, still does not work does anyone have any ideas on what I am doing wrong?

foreach (DataRow fieldtable in setofTables.Tables[0].Rows)
{

    //do work                   
    table_name = fieldtable["table_name"].ToString().Trim();
    field_name = fieldtable["field_name"].ToString().Trim();

    MessageBox.Show(table_name + field_name);

    //create parameters

    OracleParameter fieldParamater = new OracleParameter("field_name", OracleDbType.Varchar2);
    OracleParameter diffParameter = new OracleParameter("mark_diff_oracle", OracleDbType.BinaryFloat);
    OracleParameter wellIdParameter = new OracleParameter("id", OracleDbType.Char);
    //wellIdParameter.Size = 10;

    //create oracle connection and open 
    OracleConnection OrclCon2 = new OracleConnection("Data Source=" + dbname + "; User Id=" + userid + ";Password=" + password1 + ";");
    OrclCon2.Open();

    //prepare sql to be passed to oracle 
    string UpdateOraSQL = "UPDATE " +table_name+ " set :field_name = :field_name - (:mark_diff_oracle) where  id = ':id' and :field_name is not null;";
    MessageBox.Show(UpdateOraSQL);   



    //create dommand
    OracleCommand UpdateDB = new OracleCommand(UpdateOraSQL, OrclCon2);
    UpdateDB.CommandType = CommandType.Text;
    //add parameters
    UpdateDB.Parameters.Clear();
    UpdateDB.Prepare();
    UpdateDB.Parameters.Add(fieldParamater).Value = field_name;
    UpdateDB.Parameters.Add(diffParameter).Value = mark_diff_oracle;
    UpdateDB.Parameters.Add(wellIdParameter).Value = id;

Answer 1

Remove the semicolon from the end of the sql statement. Change the following code

string UpdateOraSQL = "UPDATE " +table_name+ " set :field_name = :field_name - (:mark_diff_oracle) where  id = ':id' and :field_name is not null;";

to

string UpdateOraSQL = "UPDATE " +table_name+ " set :field_name = :field_name - (:mark_diff_oracle) where  id = ':id' and :field_name is not null";

See the following link for more information

why the semicolon couldn't place in the CommandText of a OracleCommand when C#

If the problem is still not resolved, it might be helpful if you post the entire exception message also.