Invalid column name in delphi

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I have a problem with this code and I don't know how to fix it.

What I have tried:

Delphi

ADODataSet1.Close;
  if ListFiltr1.ItemIndex = 0 then
    ADODataSet1.CommandText :=
      'select [EmployeeID],LastName,FirstName,Title,City from Employees where '
      + ListeChampTxt.Items[ListeChampTxt.ItemIndex] +'= "' + TxtCherche.text +
      '" order by ' + ListTrie.Items[ListTrie.ItemIndex] + TxtTrie;
   ADODataSet1.Active := True;
   ADODataSet1.Requery();
end;

Posted 30-Jul-17 21:09pm

rezki_z

Updated 30-Jul-17 21:22pm

Graeme_Grant

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OriginalGriff · Answer 1 · 2017-07-30T21:19:00

Solution 1

Start by not doing that! Never concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead.

Then, use the debugger to find out exactly what string you are generating: I'd suspect this bit:

SQL

... order by ' + ListTrie.Items[ListTrie.ItemIndex] + TxtTrie ...

Since you don't close the quotes, and I'm pretty sure the open quote isn't what you wanted anyway, but since it all depends on the data in your fields we can't tell - and neither can you without using the debugger to find out exactly what is being sent to the DB.

Posted 30-Jul-17 21:19pm

OriginalGriff

Comments

rezki_z 31-Jul-17 3:35am

I have full code but this part show me error message and i hnow the problem is in +'="'+ but i don't hnow how to fix it

OriginalGriff 31-Jul-17 3:42am

Then use the debugger to find out exactly what you are generating. Compare that with what you wanted to generate and the problem should be obvious.

rezki_z 31-Jul-17 3:48am

This code show me this

select [EmployeeID],LastName,FirstName,Title,City from Employees where LastName= "anyname"
order by [EmployeeID] Asc
And this is not correct and i want this

select [EmployeeID],LastName,FirstName,Title,City from Employees where LastName= 'anyname'
order by [EmployeeID] Asc

But i don't know how to change it i try everything

OriginalGriff 31-Jul-17 3:59am

"The code shows me this"
No, it doesn't. You are reading what you meant to write, not what you did wrote.
Use the debugger. It's not difficult, and it will show you exactly what your code actually did.

Don't be frightened of it - it's the greatest tool you have to play with!

rezki_z 31-Jul-17 4:05am

Whay i need to find the problem and i already hnow the error but i don't know how to fix it and i already told you where is the error

OriginalGriff 31-Jul-17 4:10am

No, you don't. You have guessed "the problem is there" without looking at what you have actually done, and thinking about it. Looking at the code objectively shows what you types is not what you thought you typed.

The first stage in debugging is working out exactly what is going on, and you aren't do ing that. Yes, I *could* tell you what to do, but this is your homework, and the idea of homework is that you learn from it. Working it out for yourself - with some pretty damn big hints already - is worth doing as it gives you a foundation for debugging bigger, more complex apps later.

Yes, I know it seems like a lot of work, and unnecessary work at that. But that's how you learn a skill: by using it. So give it a try!

rezki_z 31-Jul-17 4:40am

I already find half answer and just i have problem with order by look

else if ListFiltr1.ItemIndex = 2 then
ADODataSet1.CommandText :=
'select [EmployeeID],LastName,FirstName,Title,City from Employees where '
+ ListeChampTxt.Items[ListeChampTxt.ItemIndex] + ' like ' +
quotedstr(TxtCherche.text) + '%" order by ' + ListTrie.Items[ListTrie.ItemIndex]
+ TxtTrie
else if ListFiltr1.ItemIndex = 3 then
ADODataSet1.CommandText :=
'select [EmployeeID],LastName,FirstName,Title,City from Employees where '
+ ListeChampTxt.Items[ListeChampTxt.ItemIndex] + ' like "%' +
quotedstr(TxtCherche.text) + '" order by ' + ListTrie.Items[ListTrie.ItemIndex]
+ TxtTrie
else
ADODataSet1.CommandText :=
'select [EmployeeID],LastName,FirstName,Title,City from Employees where '
+ ListeChampTxt.Items[ListeChampTxt.ItemIndex] + ' like "%' +
quotedstr(TxtCherche.text) + '%" order by ' + ListTrie.Items[ListTrie.ItemIndex]
+ TxtTrie;

ADODataSet1.Active := True;
ADODataSet1.Requery();

end;

OriginalGriff 31-Jul-17 4:48am

Yes. I know.
And if *you used the bedugger to look at what you generated* it would be obvious what the problem was.

Is there any point in me telling you what to do if you are just going to ignore it?

rezki_z 31-Jul-17 4:53am

Sorry i am here to learn but i don't hnow what you mean about debugging i think you mean start the program and read error message and i did it and give me invalid column name and sorry

OriginalGriff 31-Jul-17 5:02am

Debugging is more powerful than that! It allows you to run your code, and look at it while it's running, examining (and changing) variables while the program runs, executing it line by line so you can see exactly what it is doing, and why.

It's a very powerful tool, and one you need to get familiar with.
I can't give you explicit instructions for your particular development system (partly because I have no idea what you are using, and partly because this is a very little textbox) but Google can. Google for "debugger" and the name of your IDE and you should get full instructions.

Give it a go!

rezki_z 31-Jul-17 5:14am

I have questions you sead you cun find error inside any line how you hnow the error is belong to specific line and how you find solutions for any problem because i stock in code for week and find nothing

OriginalGriff 31-Jul-17 5:47am

:laugh:
Experience! It comes with experience, as do most things. In my case, I've been looking at code for thirty years or so, and some things just leap out at you regardless of the language used.

Practice is what gives you that - and the first thing to do is to learn how to debug things. It's the "long way round" to an extent, but it teaches you a way of thinking about problems that soon becomes second nature. That mindset lets you look at something and know it's wrong - but it takes time to develop fully.

You're stuck for so long because you aren't thinking about the "whole problem" - you are set on "that bit's right" rather than "what's wrong?". using the debugger gives you additional information, which lets you look at the problem in a different light, and that you can't easily get just by looking at the code. It's like driving a car: looks simple when your Dad does it, but when you are sat there with the engine running and you've got to pull out into moving traffic without hitting anything for the first time it's suddenly a whole load harder! That's why learner drivers aren't allowed to be alone - they need instruction and guidance (and panic braking and / or steering sometimes) from someone experienced.
In this case, that "experienced driver" is the debugger.

rezki_z 31-Jul-17 5:57am

There is some think bather me that i don't want to be collector i don't want to collect codes i want to think and write my own code and solve my own problem but its hard i can't even understand code so how i can find solutions i don't hnow what to do i have no tetcher and if i have they don't help because they don't want to be better than him i am lost

OriginalGriff 31-Jul-17 7:01am

Then get a book - Addison Wesley and Wrox do good ones - and work through it. It's not as good as a teacher (you can't ask a book questions) but it will guide you through, and hopefully not overwhelm you at the same time.
I get the feeling that you are out of your depth here at the moment, and need to take a step or two back and cover the basics better first.

rezki_z 1-Aug-17 1:36am

Thanks man i have found all the problems and fix it and the code work very well but man i love you because you help me so i want to help you to become a Muslim because only Muslim cun go to heaven i hnow you laf but take me seriously maybe you spend all your live on code but me i spend it on finding god he is the think we share skype and talk about the right religion if yiu win with evedense i will convert to your relegion if i win you convert to islam take it seriously please you don't loose any think just me talking and you asking about anithing you want and i give you the right answer thanks