Tim

Two questions:

1. What sequence are constraints tested in? I'm guessing creation order.

2. Are we going to be able customise (or as you would say customize) the violation messages? They're not very user friendly.

Roy Lambert

Roy,

<< 1. What sequence are constraints tested in? I'm guessing creation order.
>>

Yes.

<< 2. Are we going to be able customise (or as you would say customize) the
violation messages? They're not very user friendly.  >>

You can modify the edbconsts.pas unit to change the messages if you would
like.

--
Tim Young
Elevate Software
www.elevatesoft.com

> 1. What sequence are constraints tested in? I'm guessing creation order.
You should never rely on this fact, cause you can't control it (can't
arrange constraints) - I think this is not important at all and should make
no difference.

> 2. Are we going to be able customise (or as you would say customize) the
> violation messages? They're not very user friendly.
It seems like you should be able to handle error and provide custom message
depending on error code.


Regards,
Michael

Michael


>> 1. What sequence are constraints tested in? I'm guessing creation order.
>You should never rely on this fact, cause you can't control it (can't
>arrange constraints) - I think this is not important at all and should make
>no difference.

Fair enough, I was wondering because its weird that the PK being blank was noified after another non-nullable field

>> 2. Are we going to be able customise (or as you would say customize) the
>> violation messages? They're not very user friendly.
>It seems like you should be able to handle error and provide custom message
>depending on error code.

I presume you're thinking of the OnPostError event?

Roy Lambert

>>> 2. Are we going to be able customise (or as you would say customize) the
>>> violation messages? They're not very user friendly.
>> It seems like you should be able to handle error and provide custom message
>> depending on error code.
> I presume you're thinking of the OnPostError event?
Yep.


Michael

Roy,

<< Fair enough, I was wondering because its weird that the PK being blank
was noified after another non-nullable field >>

Actually, as of the build (I believe it was build 5) of EDB that added the
nullable status to columns, the nullable status is checked for all columns
prior to any constraints being checked.  However, you probably have an
actual CHECK constraint for the IS NULL check, which is why it is being
checked after the PK null checks.

--
Tim Young
Elevate Software
www.elevatesoft.com

Tim,

<< Actually, as of the build (I believe it was build 5) of EDB that added
the nullable status to columns, the nullable status is checked for all
columns prior to any constraints being checked.  >>

This is not an opinion of the order of constraint checking, but in theory
column constraints and table constraints are the same, i.e. a NOT NULL
constraint is effectively the same as a CHECK constraint making the column
not nullable. The same goes for any constraint, constraints defined at the
column level are effectively transformed to table constraint metadata.wise.

Ole Willy Tuv

Tim


Just thinking aloud. I don't know about others but it infuriates me to have error messages delivered one after another. Is there a way to get the whole lot at once and present a comprehensive error message eg in the OnPostError event?#

If not I'll just keep on suffering

Roy Lambert

Ole,

<< This is not an opinion of the order of constraint checking, but in theory
column constraints and table constraints are the same, i.e. a NOT NULL
constraint is effectively the same as a CHECK constraint making the column
not nullable. The same goes for any constraint, constraints defined at the
column level are effectively transformed to table constraint metadata.wise.
>>

Sure, and that's the way we initially had EDB designed (NOT NULL converted
into table-level CHECK constraint).  However, it is very difficult for
users/developers to deal with in terms of managing the table structures, so
we added the column-level Nullable attribute to make it more manageable.
This also jives with most of the information schema structures that are used
in CLI-compliant interfaces like ODBC.

--
Tim Young
Elevate Software
www.elevatesoft.com

Roy,

<< Just thinking aloud. I don't know about others but it infuriates me to
have error messages delivered one after another. Is there a way to get the
whole lot at once and present a comprehensive error message eg in the
OnPostError event?# >>

Well, it's done to avoid cascading error messages where all are caused by
the same issue and as a performance issue.

--
Tim Young
Elevate Software
www.elevatesoft.com