Hi, Norman,

Here's the Firebird DDL. I altered the table and field properties using IBExpert.

Note that the ID field is created without non null:

CREATE GENERATOR GEN_TBLTESTDATA_ID;

CREATE TABLE TBLTESTDATA (
ID INTEGER,
INTFIELD SMALLINT,
DESCDATA VARCHAR(255)
);

ALTER TABLE TBLTESTDATA ADD CONSTRAINT PK_TBLTESTDATA PRIMARY KEY (ID)
USING INDEX PIPPO;

SET TERM ^ ;

CREATE OR ALTER TRIGGER TBLTESTDATA_BI FOR TBLTESTDATA
ACTIVE BEFORE INSERT POSITION 0
AS
BEGIN
NEW.ID = GEN_ID(GEN_TBLTESTDATA_ID,1);
END
^

SET TERM ; ^

Cheers,

Mike

--- In firebird-support@yahoogroups.com, "Dunbar, Norman" <norman.dunbar@...> wrote:
>
> Hi Mike,
>
> >> You're right about keeping the rules and regulations of data
> >> integrity in the database rather than the application. Good
> >> working practice.
> Indeed, and one that I wish all my vendors here would follow! :-(
>
> >> Maybe Firebird is different from Oracle in that I have
> >> successfully created my ID column as a primary key without
> >> the non-null constraint. So, it's possible even if not
> >> perhaps advisable.
> Possibly not! In Oracle if I do such a thing then Oracle silently adds
> NOT NULL to the column(s) I have used in the PK.
>
> On Firebird (2.1) I can do this:
>
> SQL> create table norman (
> CON> id integer primary key,
> CON> b varchar(100));
> SQL> commit;
>
> So far so good, but ....
>
> SQL> show table norman;
> ID INTEGER Not Null
> B VARCHAR(100) Nullable
> CONSTRAINT INTEG_2: Primary key (ID)
>
> So, Firebird has quietly added NOT NULL to my ID column. Trying again,
> another way:
>
> SQL> create table norman (
> CON> id integer,
> CON> b varchar(100));
>
> SQL> alter table norman2
> CON> add constraint pk_norman2
> CON> primary key (id);
>
> Statement failed, SQLCODE = -607
> unsuccessful metadata update
> -Column: ID not defined as NOT NULL - cannot be used in PRIMARY KEY
> constraint definition.
>
> So it looks like you might have a NOT NULL constraint (back) on your ID
> columns after all? (In the latter example, Oracle would have NOT NULLed
> the ID column silently and allowed me to make the PK constraint work.)
>
>
> Cheers,
> Norman.
>
> Norman Dunbar
> Contract Senior Oracle DBA
> CIS Engineering Services
> Internal : 7 28 2051
> External : 0113 231 2051
>
>
> Information in this message may be confidential and may be legally privileged. If you have received this message by mistake, please notify the sender immediately, delete it and do not copy it to anyone else. We have checked this email and its attachments for viruses. But you should still check any attachment before opening it. We may have to make this message and any reply to it public if asked to under the Freedom of Information Act, Data Protection Act or for litigation. Email messages and attachments sent to or from any Environment Agency address may also be accessed by someone other than the sender or recipient, for business purposes. If we have sent you information and you wish to use it please read our terms and conditions which you can get by calling us on 08708 506 506. Find out more about the Environment Agency at www.environment-agency.gov.uk
>
> Information in this message may be confidential and may be legally privileged. If you have received this message by mistake, please notify the sender immediately, delete it and do not copy it to anyone else.
>
> We have checked this email and its attachments for viruses. But you should still check any attachment before opening it.
> We may have to make this message and any reply to it public if asked to under the Freedom of Information Act, Data Protection Act or for litigation. Email messages and attachments sent to or from any Environment Agency address may also be accessed by someone other than the sender or recipient, for business purposes.
>
> If we have sent you information and you wish to use it please read our terms and conditions which you can get by calling us on 08708 506 506. Find out more about the Environment Agency at www.environment-agency.gov.uk
>