Re[3]: [HACKERS] SERIAL data type

SS> sabato, 12 settembre 98, you wrote:

BGA>> t-ishii(at)sra(dot)co(dot)jp (Tatsuo Ishii) writes:
>>> A few questions for new SERIAL data type:
>>> [...]
>>> o explicit insertion to the serial column sets the value specified.
>>> This is good. However, next implicit insertion results in that
>>> previous value from the sequence + 1 is set.
>>>
>>> create table t (c text, i serial);
>>> insert into t values('a');
>>> insert into t values('b',100);
>>> insert into tvalues('c');
>>> select * from t;
>>>
>>> a 1
>>> b 100
>>> c 2
>>>
>>> This seems a little bit unnatural for me. may be i of the thrid row
>>> should be 101?

BGA>> The action above is definitely 'not right'. It is my opinion that either:

BGA>> 1. Explicit insertion into a serial column be dis-allowed.
BGA>> 2. If explicit insertion is allowed, then the sequence need to be set so
BGA>> the next implicit insertsion result in the last explicit insertion
BGA>> value + 1 being used (i.e. 101 instead of 2 in the example above).

BGA>> Of these two options, I prefer #1.

BGA>> Also, should we be able to specify a starting value for the sequence when the
BGA>> table is created? For example "create table t (c text, i serial(1000));" to
BGA>> set the starting value of the sequence to 1000.

I would like to remember there's another problem with sequences.
If you increment a sequence during a transaction and then the transaction
rolls back, the sequence's original value don't be restored.

Jose'