Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>I'd use something like this:</p> <pre><code>var Safe: IObjectSafe; cds1 : TClientDataSet; cds2 : TClientDataSet; cds3 : TClientDataSet; cds4 : TClientDataSet; begin Safe := ObjectSafe; cds1 := Safe.Guard(TClientDataSet.Create(nil)) as TClientDataSet; cds2 := Safe.Guard(TClientDataSet.Create(nil)) as TClientDataSet; cds3 := Safe.Guard(TClientDataSet.Create(nil)) as TClientDataSet; cds4 := Safe.Guard(TClientDataSet.Create(nil)) as TClientDataSet; /////////////////////////////////////////////////////////////////////// /// DO WHAT NEEDS TO BE DONE /////////////////////////////////////////////////////////////////////// // if Safe goes out of scope it will be freed and in turn free all guarded objects end; </code></pre> <p>For the implementation of the interface see <a href="http://dn.codegear.com/article/28217" rel="noreferrer">this</a> article, but you can easily create something similar yourself.</p> <p><strong>EDIT:</strong></p> <p>I just noticed that in the linked article Guard() is a procedure. In my own code I have overloaded Guard() functions that return TObject, above sample code assumes something similar. Of course with generics much better code is now possible...</p> <p><strong>EDIT 2:</strong></p> <p>If you wonder why try ... finally is completely removed in my code: It's impossible to remove the nested blocks without introducing the possibility of memory leaks (when destructors raise exceptions) or access violations. Therefore it's best to use a helper class, and let the reference counting of interfaces take over completely. The helper class can free all objects it guards, even if some of the destructors raise exceptions.</p>
    singulars
    1. This table or related slice is empty.
    1. POBest practice to do nested TRY / FINALLY statement
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USmghie
    1. USmghie
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. CONice implementation, +1 for use, but it eliminates the try finally completely which might be good enough for this example.
      singulars
      1. PO
      1. USskamradt
    2. COI see try ... finally as little more than a crutch, necessary because RAII is not possible in Delphi without interfaces. If Delphi had stack-allocated objects there would not be much need for try ... finally. Still, it could be used together with the SafeGuard interface.
      singulars
      1. PO
      1. USmghie
    3. CO@mghie: Except for cases when the destructor closes the handle or frees some other resources, which is quite often.
      singulars
      1. PO
      1. UShimself
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload