Solved

C#: adding field name to List of SQL Results

Posted on 2014-11-12
5
138 Views
Last Modified: 2014-11-20
I've written a piece to execute a SQL query and put the results into a List<object> where each record contains the fields of data from each SQL record returned. However, in my results, I no longer have the SQL field names that I can see but only have a dozen numbered fields. Is there a relatively easy way to keep the field names with the corresponding data? What I'd like to be able to do when dealing with the list is to interact with "JobID" rather than merely column 1, etc. But I've tried to write this in a generic way because this method will have to deal with many different SQL queries of varying complexity... returning anything from a single record to thousands (mostly in the 0 to several hundred range).

If you answer, please be very basic. While I've been programming for a while (almost all Delphi), I've only been working with C# for less than a week. I'm still very much in the "pirate" stage... looking for various answers online and "borrowing" and modifying to fit what I need to do. So while what I've written here works, it's is beyond my comfort level at this point. If you answer assuming that I can just pop off what's here, your answer will be over my head. (Generic suggestions to make this better or more efficient are also welcome.)

Anyway, here's what I've got so far.
    public class QueryResults : List<object[]>
    {
        public void GetData(string SQL, params object[] RequestParams)
        {
            using (FbConnection ibCon = new FbConnection(DBConnection.CreateConnString()))
            {
                try
                {
                    FbCommand cmdFBQuery = new FbCommand();

                    cmdFBQuery.Connection = ibCon;
                    cmdFBQuery.CommandType = CommandType.Text;
                    cmdFBQuery.CommandText = SQL;
                    int i = 0;
                    foreach (object obj in RequestParams)
                    {
                        cmdFBQuery.Parameters.Add(new FbParameter(i++.ToString(), obj));
                    }

                    ibCon.Open();
                    using (var reader = cmdFBQuery.ExecuteReader())
                    {
                        while (reader.Read())
                        {
                            var columns = new object[reader.FieldCount];
                            reader.GetValues(columns);
                            this.Add(columns);
                        }
                    }
                }
                catch (Exception ex)
                {
                    // handle error here
                }
            }
        }
    }

Open in new window

0
Comment
Question by:EricTaylor
  • 3
  • 2
5 Comments
 
LVL 143

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 40439277
you need to add the field names before doing the loop on the data.
however, as there is no GetColumnNames() function like the GetValues, you have to loop on the columns.
something like this (untested, not on a PC with .net installed...)

using (var reader = cmdFBQuery.ExecuteReader())
                    {
                       var columns = new object[reader.FieldCount];
                        int i = 0;
                       foreach( DBColumn f in reader.Columns)
                      {
                              columns[i++] = f.Name;
                      }
     
                        while (reader.Read())
                        {
                            var columns = new object[reader.FieldCount];
                            reader.GetValues(columns);
                            this.Add(columns);
                        }
                    }

Open in new window

0
 

Author Comment

by:EricTaylor
ID: 40443373
hmmm... this seems to have difficulties: compiler is objecting to reuse of columns and also saying that reader.Columns is invalid.

Oops... thought I responded yesterday, but this is still sitting here...
0
 
LVL 143

Accepted Solution

by:
Guy Hengel [angelIII / a3] earned 500 total points
ID: 40445673
sorry, it's not Columns, but Fields...

for ( System.Int32 iCol = 0; iCol < reader.FieldCount; iCol ++ )
  {
     columns[iCol] =reader.GetName( iCol ).ToString();
 }
0
 

Author Comment

by:EricTaylor
ID: 40451323
sorry for delay in interacting with your solution, Guy: got interrupted with another project. Will be back on this in a day or so.
0
 

Author Closing Comment

by:EricTaylor
ID: 40456454
Thanks
0

Featured Post

Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

We all know that functional code is the leg that any good program stands on when it comes right down to it, however, if your program lacks a good user interface your product may not have the appeal needed to keep your customers happy. This issue can…
Wouldn’t it be nice if you could test whether an element is contained in an array by using a Contains method just like the one available on List objects? Wouldn’t it be good if you could write code like this? (CODE) In .NET 3.5, this is possible…
This video shows how to use Hyena, from SystemTools Software, to bulk import 100 user accounts from an external text file. View in 1080p for best video quality.
I've attached the XLSM Excel spreadsheet I used in the video and also text files containing the macros used below. https://filedb.experts-exchange.com/incoming/2017/03_w12/1151775/Permutations.txt https://filedb.experts-exchange.com/incoming/201…

856 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question