Hi Massimo,

Regarding the MySQL error,  re-created the database and started a new app 
with auth.signature=True

Here is the auth_user creation log on MySQL followed by the insert that 
generates the error :

CREATE TABLE auth_user(
    id INT AUTO_INCREMENT NOT NULL,
    first_name VARCHAR(128),
    last_name VARCHAR(128),
    email VARCHAR(255),
    username VARCHAR(128),
    password VARCHAR(255),
    registration_key VARCHAR(255),
    reset_password_key VARCHAR(255),
    registration_id VARCHAR(255),
    is_active CHAR(1),
    created_on DATETIME,
    created_by INT, INDEX created_by__idx (created_by), FOREIGN KEY 
(created_by) REFERENCES auth_user(id) ON DELETE CASCADE,
    modified_on DATETIME,
    modified_by INT, INDEX modified_by__idx (modified_by), FOREIGN KEY 
(modified_by) REFERENCES auth_user(id) ON DELETE CASCADE,
    PRIMARY KEY(id)
) ENGINE=InnoDB CHARACTER SET utf8
            3 Query    COMMIT

  
INSERT INTO 
auth_user(username,first_name,last_name,modified_by,is_active,registration_id,created_by,
reset_password_key,created_on,modified_on,password,registration_key,email) 
VALUES ('rakesh','Rakesh','Singh',0,'T','',0,'','2012-04-10 
20:47:09','2012-04-10 20:47:09',
'0835d7189a6927648202bd9d8a8562a8','','rakeshsingh...@gmail.com')
            6 Query    ROLLBACK

Manually executing the insert returns:
ERROR 1452 (23000): Cannot add or update a child row: a foreign key 
constraint fails (`web2py_dev`.`auth_user`, CONSTRAINT `auth_user_ibfk_1` 
FOREIGN KEY (`created_by`) REFERENCES `auth_user` (`id`) ON DELETE CASCADE)


Which makes sense, since the value for created_by (and modified_by) 
defaults to 0 and that ID does not exist in auth_user.id
Modifying the created_by and modified_by values to NULL allows this record 
to be inserted.

Thank you for your help once again.

Regards,

Rakesh









>> On Tue, Apr 10, 2012 at 9:33 AM, Massimo Di Pierro <
>> massimo.dipie...@gmail.com> wrote:
>>
>>> Actually I was wrong. this is not the problem. Web2py does the right 
>>> thing. Is there any way you can look into the mysql logs what is the sql 
>>> string that causes the problem?
>>>
>>>
>>> On Tuesday, 10 April 2012 08:23:03 UTC-5, Massimo Di Pierro wrote:
>>>>
>>>> I figured this out. The table has a self reference and web2py inserts a 
>>>> zero in it instead of NULL. Works for sqlite but not MySQL.
>>>> Changing zero with NULL may be treated as a bug fix it will constitute 
>>>> a minor change of backward compatibility in case you incorrectly do 
>>>>
>>>> db(db.table.reference_field==**0).select()
>>>>
>>>> while the correct thing to do would be 
>>>>
>>>> db(~(db.table.reference_field>**0)).select() 
>>>>
>>>> I will try fix it and then will ask for comments.
>>>>
>>>> On Monday, 9 April 2012 18:29:10 UTC-5, tomt wrote:
>>>>>
>>>>> I have declared the table in db.py with auth.signature, and 
>>>>> uncommented auth.enable_record_versioning(**db), but the _archive 
>>>>> table isn't created.
>>>>>  - Tom
>>>>>
>>>>> On Monday, April 9, 2012 8:33:18 AM UTC-6, Massimo Di Pierro wrote:
>>>>>>
>>>>>> the signature=True only adds a signature to the auth_* tables so that 
>>>>>> if a user creates an account for another user or creates a group, you 
>>>>>> can 
>>>>>> keep track of who did it.
>>>>>>
>>>>>> The mything_archive table should be created by:
>>>>>>
>>>>>> auth.enable_record_versioning(**db)
>>>>>>
>>>>>> This should be called after the mything table is defined. Does it 
>>>>>> work?
>>>>>>
>>>>>> On Sunday, 8 April 2012 22:08:47 UTC-5, tomt wrote:
>>>>>>>
>>>>>>> Hi,
>>>>>>> Thanks for your response.  I deleted the database as you suggested 
>>>>>>> and changed signature=False.  The problem did go away and I was able to 
>>>>>>> add 
>>>>>>> users without the error.  
>>>>>>> I then reverted to signature=True.  While subsequent modifications 
>>>>>>> did show the signature, the 'mything_archive' was never created.
>>>>>>>
>>>>>>> - Tom
>>>>>>>
>>>>>>> On Sunday, April 8, 2012 9:04:14 AM UTC-6, Massimo Di Pierro wrote:
>>>>>>>>
>>>>>>>> Can you try again with mysql, delete the database and replace:
>>>>>>>>
>>>>>>>> auth.define_tables(signature=**True)
>>>>>>>> with
>>>>>>>> auth.define_tables(signature=**False)
>>>>>>>>
>>>>>>>> Does the problem does away? It looks like it does not like the self 
>>>>>>>> reference in auth_user. 
>>>>>>>>
>>>>>>>> On Saturday, 7 April 2012 22:09:31 UTC-5, tomt wrote:
>>>>>>>>>
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>> I tried using your new versioning feature in trunk.
>>>>>>>>> I created an app using a mysql database:
>>>>>>>>> db = DAL('mysql://version:version@**localhost/version')
>>>>>>>>> When I used the admin function to define a new user
>>>>>>>>> I received the following error:
>>>>>>>>> ..............................**..........
>>>>>>>>> <class 'gluon.contrib.pymysql.err.**IntegrityError'> 
>>>>>>>>> (1452, u'Cannot add or update a child row: a foreign key 
>>>>>>>>> constraint fails 
>>>>>>>>> (`version/auth_user`, CONSTRAINT `auth_user_ibfk_1` 
>>>>>>>>> FOREIGN KEY (`created_by`) REFERENCES `auth_user` (`id`) ON DELETE 
>>>>>>>>> CASCADE)')
>>>>>>>>> ..............................**..........
>>>>>>>>>
>>>>>>>>> I rebuilt the app to use sqlite instead of mysql:
>>>>>>>>> db = DAL('sqlite://storage.sqlite')
>>>>>>>>>
>>>>>>>>> I was then able to add a user without the error
>>>>>>>>>
>>>>>>>>> I was using MySQL client version: 5.0.84
>>>>>>>>>
>>>>>>>>> - any suggestions?  - Tom
>>>>>>>>>
>>>>>>>>> On Thursday, April 5, 2012 4:16:04 PM UTC-6, Massimo Di Pierro 
>>>>>>>>> wrote:
>>>>>>>>>>
>>>>>>>>>> This is how it works:
>>>>>>>>>>
>>>>>>>>>> # define auth 
>>>>>>>>>> auth = Auth(db, hmac_key=Auth.get_or_create_**key())
>>>>>>>>>> auth.define_tables(username=**True,signature=True)
>>>>>>>>>>
>>>>>>>>>> # define your own tables like
>>>>>>>>>> db.define_table('mything',**Field('name'),auth.signature)
>>>>>>>>>>
>>>>>>>>>> # than do:
>>>>>>>>>> auth.enable_record_versioning(**db)
>>>>>>>>>>
>>>>>>>>>> how does it work? every table, including auth_user will have an 
>>>>>>>>>> auth.signature including created_by, created_on, modified_by, 
>>>>>>>>>> modified_on, 
>>>>>>>>>> is_active fields. When a record of table mything (or any other 
>>>>>>>>>> table) is 
>>>>>>>>>> modified, a copy of the previous record is copied into 
>>>>>>>>>> mything_archive 
>>>>>>>>>> which references the current record. When a record is deleted, it is 
>>>>>>>>>> not 
>>>>>>>>>> actually deleted but is_active is set to False, all records with 
>>>>>>>>>> is_active==False are filtered out in searches except in appadmin.
>>>>>>>>>>
>>>>>>>>>> Pros:
>>>>>>>>>> - your app will get full record archival for auditing purposes
>>>>>>>>>> - could not be simpler. nothing else to do. Try with 
>>>>>>>>>> SQLFORM.grid(db.mything) for example.
>>>>>>>>>> - does not break references and there is no need for uuids
>>>>>>>>>> - does not slow down searches because archive is done in separate 
>>>>>>>>>> archive tables
>>>>>>>>>>
>>>>>>>>>> Cons:
>>>>>>>>>> - uses lots of extra memory because every version of a record is 
>>>>>>>>>> stored (it would be more efficient to store changes only but that 
>>>>>>>>>> would 
>>>>>>>>>> make more difficult to do auditing).
>>>>>>>>>> - slows down db(...).update(...) for multi record because it 
>>>>>>>>>> needs to copy all records needing update from the original table to 
>>>>>>>>>> the 
>>>>>>>>>> archive table. This requires selecting all the records.
>>>>>>>>>>
>>>>>>>>>> Comments? Suggestions?
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>
On Tuesday, 10 April 2012 18:53:05 UTC+2, Massimo Di Pierro wrote:
>
> I agree that is people would normally use the feature. And that's a matter 
> of deleting older archived records. What I am not sure is if it should be 
> built-in into web2py.
>
> If would be easy to do db(db.table_archive).delete() which event should 
> trigger it? perhaps this is one of those actions should be 
> called explicitly and not done automatically.
>
> On Tuesday, 10 April 2012 09:22:44 UTC-5, Richard wrote:
>>
>> Hi,
>>
>> It looks like a great new feature... I would suggest something. Instead 
>> of copying every update, I would keep the records only once the it gets in 
>> a particular state. In my case a records could have no review, can be 
>> reviewed and approved, so I just want to keep the changes that occured once 
>> the records have been reviewed. Before that it is only noise to me. I mean 
>> if the records don't need a review process I don't need the audit trail and 
>> if it needs a review or an approval I only need to audit the change after 
>> it has been review once what happen before I don't care. I think it is a 
>> really good trade off between size of the database and an audit trail 
>> feature. But it means that you have to build a reviewing process feature... 
>> It could be option maybe, I mean audit all vs audit after get the state 
>> review.
>>
>> Thanks for this Massimo any way our lives can't be easier without you :)
>>
>> Richard
>>
>> On Tue, Apr 10, 2012 at 9:33 AM, Massimo Di Pierro <
>> massimo.dipie...@gmail.com> wrote:
>>
>>> Actually I was wrong. this is not the problem. Web2py does the right 
>>> thing. Is there any way you can look into the mysql logs what is the sql 
>>> string that causes the problem?
>>>
>>>
>>> On Tuesday, 10 April 2012 08:23:03 UTC-5, Massimo Di Pierro wrote:
>>>>
>>>> I figured this out. The table has a self reference and web2py inserts a 
>>>> zero in it instead of NULL. Works for sqlite but not MySQL.
>>>> Changing zero with NULL may be treated as a bug fix it will constitute 
>>>> a minor change of backward compatibility in case you incorrectly do 
>>>>
>>>> db(db.table.reference_field==**0).select()
>>>>
>>>> while the correct thing to do would be 
>>>>
>>>> db(~(db.table.reference_field>**0)).select() 
>>>>
>>>> I will try fix it and then will ask for comments.
>>>>
>>>> On Monday, 9 April 2012 18:29:10 UTC-5, tomt wrote:
>>>>>
>>>>> I have declared the table in db.py with auth.signature, and 
>>>>> uncommented auth.enable_record_versioning(**db), but the _archive 
>>>>> table isn't created.
>>>>>  - Tom
>>>>>
>>>>> On Monday, April 9, 2012 8:33:18 AM UTC-6, Massimo Di Pierro wrote:
>>>>>>
>>>>>> the signature=True only adds a signature to the auth_* tables so that 
>>>>>> if a user creates an account for another user or creates a group, you 
>>>>>> can 
>>>>>> keep track of who did it.
>>>>>>
>>>>>> The mything_archive table should be created by:
>>>>>>
>>>>>> auth.enable_record_versioning(**db)
>>>>>>
>>>>>> This should be called after the mything table is defined. Does it 
>>>>>> work?
>>>>>>
>>>>>> On Sunday, 8 April 2012 22:08:47 UTC-5, tomt wrote:
>>>>>>>
>>>>>>> Hi,
>>>>>>> Thanks for your response.  I deleted the database as you suggested 
>>>>>>> and changed signature=False.  The problem did go away and I was able to 
>>>>>>> add 
>>>>>>> users without the error.  
>>>>>>> I then reverted to signature=True.  While subsequent modifications 
>>>>>>> did show the signature, the 'mything_archive' was never created.
>>>>>>>
>>>>>>> - Tom
>>>>>>>
>>>>>>> On Sunday, April 8, 2012 9:04:14 AM UTC-6, Massimo Di Pierro wrote:
>>>>>>>>
>>>>>>>> Can you try again with mysql, delete the database and replace:
>>>>>>>>
>>>>>>>> auth.define_tables(signature=**True)
>>>>>>>> with
>>>>>>>> auth.define_tables(signature=**False)
>>>>>>>>
>>>>>>>> Does the problem does away? It looks like it does not like the self 
>>>>>>>> reference in auth_user. 
>>>>>>>>
>>>>>>>> On Saturday, 7 April 2012 22:09:31 UTC-5, tomt wrote:
>>>>>>>>>
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>> I tried using your new versioning feature in trunk.
>>>>>>>>> I created an app using a mysql database:
>>>>>>>>> db = DAL('mysql://version:version@**localhost/version')
>>>>>>>>> When I used the admin function to define a new user
>>>>>>>>> I received the following error:
>>>>>>>>> ..............................**..........
>>>>>>>>> <class 'gluon.contrib.pymysql.err.**IntegrityError'> 
>>>>>>>>> (1452, u'Cannot add or update a child row: a foreign key 
>>>>>>>>> constraint fails 
>>>>>>>>> (`version/auth_user`, CONSTRAINT `auth_user_ibfk_1` 
>>>>>>>>> FOREIGN KEY (`created_by`) REFERENCES `auth_user` (`id`) ON DELETE 
>>>>>>>>> CASCADE)')
>>>>>>>>> ..............................**..........
>>>>>>>>>
>>>>>>>>> I rebuilt the app to use sqlite instead of mysql:
>>>>>>>>> db = DAL('sqlite://storage.sqlite')
>>>>>>>>>
>>>>>>>>> I was then able to add a user without the error
>>>>>>>>>
>>>>>>>>> I was using MySQL client version: 5.0.84
>>>>>>>>>
>>>>>>>>> - any suggestions?  - Tom
>>>>>>>>>
>>>>>>>>> On Thursday, April 5, 2012 4:16:04 PM UTC-6, Massimo Di Pierro 
>>>>>>>>> wrote:
>>>>>>>>>>
>>>>>>>>>> This is how it works:
>>>>>>>>>>
>>>>>>>>>> # define auth 
>>>>>>>>>> auth = Auth(db, hmac_key=Auth.get_or_create_**key())
>>>>>>>>>> auth.define_tables(username=**True,signature=True)
>>>>>>>>>>
>>>>>>>>>> # define your own tables like
>>>>>>>>>> db.define_table('mything',**Field('name'),auth.signature)
>>>>>>>>>>
>>>>>>>>>> # than do:
>>>>>>>>>> auth.enable_record_versioning(**db)
>>>>>>>>>>
>>>>>>>>>> how does it work? every table, including auth_user will have an 
>>>>>>>>>> auth.signature including created_by, created_on, modified_by, 
>>>>>>>>>> modified_on, 
>>>>>>>>>> is_active fields. When a record of table mything (or any other 
>>>>>>>>>> table) is 
>>>>>>>>>> modified, a copy of the previous record is copied into 
>>>>>>>>>> mything_archive 
>>>>>>>>>> which references the current record. When a record is deleted, it is 
>>>>>>>>>> not 
>>>>>>>>>> actually deleted but is_active is set to False, all records with 
>>>>>>>>>> is_active==False are filtered out in searches except in appadmin.
>>>>>>>>>>
>>>>>>>>>> Pros:
>>>>>>>>>> - your app will get full record archival for auditing purposes
>>>>>>>>>> - could not be simpler. nothing else to do. Try with 
>>>>>>>>>> SQLFORM.grid(db.mything) for example.
>>>>>>>>>> - does not break references and there is no need for uuids
>>>>>>>>>> - does not slow down searches because archive is done in separate 
>>>>>>>>>> archive tables
>>>>>>>>>>
>>>>>>>>>> Cons:
>>>>>>>>>> - uses lots of extra memory because every version of a record is 
>>>>>>>>>> stored (it would be more efficient to store changes only but that 
>>>>>>>>>> would 
>>>>>>>>>> make more difficult to do auditing).
>>>>>>>>>> - slows down db(...).update(...) for multi record because it 
>>>>>>>>>> needs to copy all records needing update from the original table to 
>>>>>>>>>> the 
>>>>>>>>>> archive table. This requires selecting all the records.
>>>>>>>>>>
>>>>>>>>>> Comments? Suggestions?
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>
On Tuesday, 10 April 2012 18:53:05 UTC+2, Massimo Di Pierro wrote:
>
> I agree that is people would normally use the feature. And that's a matter 
> of deleting older archived records. What I am not sure is if it should be 
> built-in into web2py.
>
> If would be easy to do db(db.table_archive).delete() which event should 
> trigger it? perhaps this is one of those actions should be 
> called explicitly and not done automatically.
>
> On Tuesday, 10 April 2012 09:22:44 UTC-5, Richard wrote:
>>
>> Hi,
>>
>> It looks like a great new feature... I would suggest something. Instead 
>> of copying every update, I would keep the records only once the it gets in 
>> a particular state. In my case a records could have no review, can be 
>> reviewed and approved, so I just want to keep the changes that occured once 
>> the records have been reviewed. Before that it is only noise to me. I mean 
>> if the records don't need a review process I don't need the audit trail and 
>> if it needs a review or an approval I only need to audit the change after 
>> it has been review once what happen before I don't care. I think it is a 
>> really good trade off between size of the database and an audit trail 
>> feature. But it means that you have to build a reviewing process feature... 
>> It could be option maybe, I mean audit all vs audit after get the state 
>> review.
>>
>> Thanks for this Massimo any way our lives can't be easier without you :)
>>
>> Richard
>>
>> On Tue, Apr 10, 2012 at 9:33 AM, Massimo Di Pierro <
>> massimo.dipie...@gmail.com> wrote:
>>
>>> Actually I was wrong. this is not the problem. Web2py does the right 
>>> thing. Is there any way you can look into the mysql logs what is the sql 
>>> string that causes the problem?
>>>
>>>
>>> On Tuesday, 10 April 2012 08:23:03 UTC-5, Massimo Di Pierro wrote:
>>>>
>>>> I figured this out. The table has a self reference and web2py inserts a 
>>>> zero in it instead of NULL. Works for sqlite but not MySQL.
>>>> Changing zero with NULL may be treated as a bug fix it will constitute 
>>>> a minor change of backward compatibility in case you incorrectly do 
>>>>
>>>> db(db.table.reference_field==**0).select()
>>>>
>>>> while the correct thing to do would be 
>>>>
>>>> db(~(db.table.reference_field>**0)).select() 
>>>>
>>>> I will try fix it and then will ask for comments.
>>>>
>>>> On Monday, 9 April 2012 18:29:10 UTC-5, tomt wrote:
>>>>>
>>>>> I have declared the table in db.py with auth.signature, and 
>>>>> uncommented auth.enable_record_versioning(**db), but the _archive 
>>>>> table isn't created.
>>>>>  - Tom
>>>>>
>>>>> On Monday, April 9, 2012 8:33:18 AM UTC-6, Massimo Di Pierro wrote:
>>>>>>
>>>>>> the signature=True only adds a signature to the auth_* tables so that 
>>>>>> if a user creates an account for another user or creates a group, you 
>>>>>> can 
>>>>>> keep track of who did it.
>>>>>>
>>>>>> The mything_archive table should be created by:
>>>>>>
>>>>>> auth.enable_record_versioning(**db)
>>>>>>
>>>>>> This should be called after the mything table is defined. Does it 
>>>>>> work?
>>>>>>
>>>>>> On Sunday, 8 April 2012 22:08:47 UTC-5, tomt wrote:
>>>>>>>
>>>>>>> Hi,
>>>>>>> Thanks for your response.  I deleted the database as you suggested 
>>>>>>> and changed signature=False.  The problem did go away and I was able to 
>>>>>>> add 
>>>>>>> users without the error.  
>>>>>>> I then reverted to signature=True.  While subsequent modifications 
>>>>>>> did show the signature, the 'mything_archive' was never created.
>>>>>>>
>>>>>>> - Tom
>>>>>>>
>>>>>>> On Sunday, April 8, 2012 9:04:14 AM UTC-6, Massimo Di Pierro wrote:
>>>>>>>>
>>>>>>>> Can you try again with mysql, delete the database and replace:
>>>>>>>>
>>>>>>>> auth.define_tables(signature=**True)
>>>>>>>> with
>>>>>>>> auth.define_tables(signature=**False)
>>>>>>>>
>>>>>>>> Does the problem does away? It looks like it does not like the self 
>>>>>>>> reference in auth_user. 
>>>>>>>>
>>>>>>>> On Saturday, 7 April 2012 22:09:31 UTC-5, tomt wrote:
>>>>>>>>>
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>> I tried using your new versioning feature in trunk.
>>>>>>>>> I created an app using a mysql database:
>>>>>>>>> db = DAL('mysql://version:version@**localhost/version')
>>>>>>>>> When I used the admin function to define a new user
>>>>>>>>> I received the following error:
>>>>>>>>> ..............................**..........
>>>>>>>>> <class 'gluon.contrib.pymysql.err.**IntegrityError'> 
>>>>>>>>> (1452, u'Cannot add or update a child row: a foreign key 
>>>>>>>>> constraint fails 
>>>>>>>>> (`version/auth_user`, CONSTRAINT `auth_user_ibfk_1` 
>>>>>>>>> FOREIGN KEY (`created_by`) REFERENCES `auth_user` (`id`) ON DELETE 
>>>>>>>>> CASCADE)')
>>>>>>>>> ..............................**..........
>>>>>>>>>
>>>>>>>>> I rebuilt the app to use sqlite instead of mysql:
>>>>>>>>> db = DAL('sqlite://storage.sqlite')
>>>>>>>>>
>>>>>>>>> I was then able to add a user without the error
>>>>>>>>>
>>>>>>>>> I was using MySQL client version: 5.0.84
>>>>>>>>>
>>>>>>>>> - any suggestions?  - Tom
>>>>>>>>>
>>>>>>>>> On Thursday, April 5, 2012 4:16:04 PM UTC-6, Massimo Di Pierro 
>>>>>>>>> wrote:
>>>>>>>>>>
>>>>>>>>>> This is how it works:
>>>>>>>>>>
>>>>>>>>>> # define auth 
>>>>>>>>>> auth = Auth(db, hmac_key=Auth.get_or_create_**key())
>>>>>>>>>> auth.define_tables(username=**True,signature=True)
>>>>>>>>>>
>>>>>>>>>> # define your own tables like
>>>>>>>>>> db.define_table('mything',**Field('name'),auth.signature)
>>>>>>>>>>
>>>>>>>>>> # than do:
>>>>>>>>>> auth.enable_record_versioning(**db)
>>>>>>>>>>
>>>>>>>>>> how does it work? every table, including auth_user will have an 
>>>>>>>>>> auth.signature including created_by, created_on, modified_by, 
>>>>>>>>>> modified_on, 
>>>>>>>>>> is_active fields. When a record of table mything (or any other 
>>>>>>>>>> table) is 
>>>>>>>>>> modified, a copy of the previous record is copied into 
>>>>>>>>>> mything_archive 
>>>>>>>>>> which references the current record. When a record is deleted, it is 
>>>>>>>>>> not 
>>>>>>>>>> actually deleted but is_active is set to False, all records with 
>>>>>>>>>> is_active==False are filtered out in searches except in appadmin.
>>>>>>>>>>
>>>>>>>>>> Pros:
>>>>>>>>>> - your app will get full record archival for auditing purposes
>>>>>>>>>> - could not be simpler. nothing else to do. Try with 
>>>>>>>>>> SQLFORM.grid(db.mything) for example.
>>>>>>>>>> - does not break references and there is no need for uuids
>>>>>>>>>> - does not slow down searches because archive is done in separate 
>>>>>>>>>> archive tables
>>>>>>>>>>
>>>>>>>>>> Cons:
>>>>>>>>>> - uses lots of extra memory because every version of a record is 
>>>>>>>>>> stored (it would be more efficient to store changes only but that 
>>>>>>>>>> would 
>>>>>>>>>> make more difficult to do auditing).
>>>>>>>>>> - slows down db(...).update(...) for multi record because it 
>>>>>>>>>> needs to copy all records needing update from the original table to 
>>>>>>>>>> the 
>>>>>>>>>> archive table. This requires selecting all the records.
>>>>>>>>>>
>>>>>>>>>> Comments? Suggestions?
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>

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