Question

I am working on a project, and I have hit a brick wall. My code adds dates with a type to a database, but I need to create an error when there is already a similar entry within the code. However, I cannot get my loop to check for duplicates, and instead it adds duplicates! I am not very good at loops so I’m a bit stuck at this. Any help to check for duplicate entries and to stop it from creating too many would be a great help! Changed my code within this text area so it’s not exactly the same variable names.

Here is my code: –

if (DT != null && DT.Length > 0 || DF != null && DF.Length > 0)
            {
                for (int t = 0; t < Type.Length; t++)
                {
                    DateTime checkDate;

                    if (Type.IsSelectionValid(8, out typeError) && DateTime.TryParse(DF, out typeError) && DateTime.TryParse(DT, out checkDate))
                    {
                            TypeValid = true;
                            error.Error = false;
                        }
                        else
                        {
                            error.Errors = "Type-Invalid";
                            absenceTypeValid = false;
                            break;
                        }
                    }
                    else
                    {
                        error.Errors = "Type-Duplicate";
                        TypeValid = false;
                        break;
                    }
                }
            }

Answer 1

I’m ‘fairly’ sure you are going out of your way to make a problem more difficult than it is here, but I can’t say for sure since I’m not entirely sure what this is doing.

But here are the conditions that need to be met to get to your Type-Duplicate Error line:

1) Either DT or DF have to not be empty to get past the first if statement

2) Either IsSelectionValid() has to return false or either DT or DF have to be an invalid DateTime.

None of those things constitute a duplicate.

Let me try to explain what I see here:

I first see variables called DT, DF. I can see these are dates, but that’s all I know about them. I see ‘Type’ which I understand even less about than DT and DF. I see that you are doing a loop for Type.Length number of iterations… but what does this mean to me if I don’t have a clue what Type is?

If you had comments explaining what things are I ‘might’ be able to help you, but there’s just really not enough information to know what’s happening here.

If you simply want to know how to avoid adding duplicates to a database, then I would suggest adding a constraint or index to the column in the database and then you can just catch the exceptions that are thrown when you try to insert a duplicate and deal with it that way. Alternatively, account for it in your insert statement.