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Programming => Databases => Topic started by: Weitentaaal on November 17, 2020, 02:51:42 pm

Title: Error Handlicng when Table Doesn't Exists
Post by: Weitentaaal on November 17, 2020, 02:51:42 pm

Hey Guys,

So i Got This Code:

Code: Pascal  [Select][+][-]

1. try
2.      MacAd := dbHist.FieldByName('ProgID').AsString;
3. except
4.       on E : EDatabaseError do begin
5.            //ShowMessage('DB ERROR:' + ' ' + E.ClassName + ' ' + E.Message);
6.           //If This Table (RollBK) Doesnt Exists, then create it -->
7.           //SQL := 'CREATE TABLE ROLLBK (Td DATE, Tt TIME, Zeichnung INTEGER, Part INTEGER, Act INTEGER, Pid TEXT(20));';
8.       end;
9.    end;
10.  

Any1 any Idea how i Can do this ?

Thanks A Lot :)

Title: Re: Error Handlicng when Table Doesn't Exists
Post by: Zvoni on November 17, 2020, 03:29:33 pm

Huh?

https://www.freepascal.org/docs-html/fcl/sqldb/tsqlconnection.gettablenames.html

Why not just look it up beforehand?

Title: Re: Error Handlicng when Table Doesn't Exists
Post by: Weitentaaal on November 18, 2020, 10:31:55 am

i just searched for the Wrong Thing Sorry :o

Title: Re: Error Handlicng when Table Doesn't Exists
Post by: rvk on November 18, 2020, 10:38:48 am

And besides that... you have the try/except around the wrong code. That will only trigger the except if there is no FIELD ProgID.

If you use a table which doesn't exists (like stated in your title) you need to put the sql.open (with SELECT) inside try/except. Then you can examine the exception if it contains "table not found" or something (depending on your database).

Checking beforehand with gettablenames would indeed be preferable over exceptionhandling.

Title: Re: Error Handlicng when Table Doesn't Exists
Post by: Weitentaaal on November 25, 2020, 10:26:26 am

Thanks rvk :)

Understand this whole thing better now.
I went with the gettablenames :)