Difference between StartTransaction and Active:= True;
lazarus / 16-Databases

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egsuh · 2020-04-27 09:08

Hi,

I used to use  syntax as following, because this was the way Delphi
books explained.

   if not SQLTransaction1.Active then
SQLTransaction1.StartTransaction;

But I'm just curious following statement does what the previous one
does.

    SQLTransaction1.Active := True;

Does this start a new transaction if the transaction was not active ,
and do nothing if it was active?

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eljo · 2020-04-27 09:24

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TDBTransaction.SetActive(Value : boolean);begin  if FActive and (not
Value) then    EndTransaction  else if (not FActive) and Value then  
if csLoading in ComponentState then // if the properties are not
finished loading yet      begin      FOpenAfterRead := true; // call
start transaction at a later time.      exit;      end    else      
StartTransaction; end; So as you can see setting active true at
runtime will call startTransaction so yeah its the same.

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rvk · 2020-04-27 09:29

Quote from: eljo on April 27, 2020, 11:24:46 amCode: Pascal
 [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TDBTransaction.SetActive(Value : boolean);begin  if FActive and (not
Value) then    EndTransaction  else if (not FActive) and Value then  
if csLoading in ComponentState then // if the properties are not
finished loading yet      begin      FOpenAfterRead := true; // call
start transaction at a later time.      exit;      end    else      
StartTransaction; end; So as you can see setting active true at
runtime will call startTransaction so yeah its the same.
You missed something in the code   You see a "not FActive" in the
second if.
So setting Active to true will ONLY call starttransaction if the
transaction isn't already started.
That's different from just calling starttransaction.

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eljo · 2020-04-27 09:31

Nope you missed the code compared to and I quote.

Quote from: egsuh on April 27, 2020, 11:08:46 amI used to use  syntax
as following, because this was the way Delphi books explained.

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i    if not
SQLTransaction1.Active then SQLTransaction1.StartTransaction; 
So yes setting active to true is equivalent with the code above.

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egsuh · 2020-04-27 09:34

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i if
csLoading in ComponentState then // if the properties are not finished
loading yet      begin      FOpenAfterRead := true; // call start
transaction at a later time.      exit;      end
I'm not sure about the above codes, but except that it seems to act as
I want.
For example,

   Transaction.Active := True;   // Starts transaction if not active,
and do nothing if already active
   Transaction.Active := False;   // Closes transaction if active,
possibly using default action


Many thanks to you guys for kind comments.

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eljo · 2020-04-27 09:38

Quote from: egsuh on April 27, 2020, 11:34:56 amCode: Pascal
 [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i if
csLoading in ComponentState then // if the properties are not finished
loading yet      begin      FOpenAfterRead := true; // call start
transaction at a later time.      exit;      end
I'm not sure about the above codes, but except that it seems to act as
I want.
For example,

   Transaction.Active := True;   // Starts transaction if not active,
and do nothing if already active
   Transaction.Active := False;   // Closes transaction if active,
possibly using default action
Your assumption is correct it uses the default Action to determinate
what to do when endtransaction is called.

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rvk · 2020-04-27 09:48

Quote from: eljo on April 27, 2020, 11:31:57 amNope you missed the
code compared to and I quote.
Quote from: egsuh on April 27, 2020, 11:08:46 amI used to use  syntax
as following, because this was the way Delphi books explained.
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i    if not
SQLTransaction1.Active then SQLTransaction1.StartTransaction; So yes
setting active to true is equivalent with the code above.

Ah, Ok, Sorry. I only reacted to your statement (especially the words
marked in bold):
Quote from: eljo on April 27, 2020, 11:24:46 amSo as you can see
setting active true at runtime will call startTransaction so yeah its
the same.
Didn't realize you responded to the snippet gives.