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


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