Thanks Kerry, I already have that working ( or very similar) from back
before I woke up to generators, but we did have some problems with deadlocks
on this when it was getting hit hard. Max you know about this problem as
well I think. Anyway, seems like thats the method to use with SQL Server
oui? It looks like Midas will give us an opportunity to control the code a
lot better, and avoid deadlock situations anyway. Using generators you never
ever get deadlock situations, not something you ever have to worry about.
Should this have been on another list? Database? How please?
-----Original Message-----
From: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
To: Multiple recipients of list database <[EMAIL PROTECTED]>
Date: Wednesday, 3 November 1999 16:36
Subject: [DUG-DB]: Re: [DUG]: Generators - Sequences, and Identities
>
>
>[ I moved this to 'database' too ]
>
>> OK. Thats what I meant by an increment table. Do you experiance any
>deadlock
>> issues with this idea?
>
>As long as you don't access the table inside a transaction, and don't care
>if you lose the odd sequence number, you should be fine.
>
>Implement something like this (except make it syntactically correct):
>
>create table incrementTable( keyid : varchar, nextValue : integer );
>
>function getNextSequence( keyid : String ) : integer
>var originalValue : integer;
> newValue : integer;
>begin
> repeat
> with Query1 do
> begin
> SQL.Add('select nextValue from incrementTable
> where keyid = :keyid');
>
> Params[0].AsString := keyid;
> Open;
> originalValue := fieldByName('nextValue');
>
> newValue := originalValue + 1;
>
> SQL.Clear;
> SQl.Add('update incrementTable
> set nextValue = :newValue
> where keyid = :keyid
> and nextValue = :originalValue');
>
> ParamsAsAppropriate :-)
> ExecSQL;
>
> // See if the update worked
> until Query1.RowsAffected = 1;
>
> result := newValue;
>end;
>
>
>Cheers,
>Kerry S
>PS: That's about right, isn't it Greg?
>
>-----Original Message-----
>From: Julien Thomas <[EMAIL PROTECTED]>
>To: Multiple recipients of list delphi <[EMAIL PROTECTED]>
>Date: Wednesday, 3 November 1999 3:53 PM
>Subject: RE: [DUG]: Generators - Sequences, and Identities
>
>
>>We use a separate table to maintain the nextID for all the tables.
>>
>>> -----Original Message-----
>>> From: Tony Blomfield [SMTP:[EMAIL PROTECTED]]
>>> Sent: Wednesday, November 03, 1999 3:47 PM
>>> To: Multiple recipients of list delphi
>>> Subject: [DUG]: Generators - Sequences, and Identities
>>>
>>> Unless I have missunderstood, SQL7 has no equivolent of Interbases
>>> generators, or Oracles Sequences? Instead it has the identity data type
>>> which is akin to Access or paradox Autoincrement columns.
>>>
>>> The only time you seem to be able to see what your identity value was/is
>>> is
>>> immediatly following a insert statement.
>>>
>>> Coming form an Interbase background for the last few years, this idea of
>>> identity columns looks very decadent, and extremely shortsighted of
>>> MS/Sybase, and really surprised me that it is still like this.
>>>
>>> So what about the multi user situation. Can we guarantee that Select
>>> Identity@@ will allways get the last identity for this specific user?
>>>
>>> What a dumb dumb idea. It more or less completely ignores the concept of
>>> using surrogate keys.
>>>
>>> What do others do about this for MSSQL based Delphi Apps? It seems to me
>>> that the only reasonable approach is to use an increment table, and
>>> copmpletely abandon the Indentity concept. What are others doing here?
>>>
>>> Thanks,
>>>
>>> Tony.
>>>
>>>
>-------------------------------------------------------------------------
>-
>>> -
>>> New Zealand Delphi Users group - Delphi List - [EMAIL PROTECTED]
>>> Website: http://www.delphi.org.nz
>>
>---------------------------------------------------------------------------
>> New Zealand Delphi Users group - Delphi List - [EMAIL PROTECTED]
>> Website: http://www.delphi.org.nz
>
>---------------------------------------------------------------------------
> New Zealand Delphi Users group - Delphi List - [EMAIL PROTECTED]
> Website: http://www.delphi.org.nz
>
>
>
>
>---------------------------------------------------------------------------
> New Zealand Delphi Users group - Database List - [EMAIL PROTECTED]
> Website: http://www.delphi.org.nz
---------------------------------------------------------------------------
New Zealand Delphi Users group - Database List - [EMAIL PROTECTED]
Website: http://www.delphi.org.nz
