Re: A couple of newbie questions ...

Raymond O'Donnell wrote:

>> 1. Is a SEQUENCE what I use instead of auto_increment?
>
> Yes. The easiest thing is to define the column as type SERIAL - this
> will create the sequence for you and associate it with the column.
> Alternatively, you can create the sequence by hand, create the column
> as an integer type, and then set the default for the column as
> nextval('<sequence name>'). Have a look in the docs for the gory
> details:
>
> http://www.postgresql.org/docs/8.3/static/datatype-numeric.html#DATATYPE-SERIAL
>

Of sorts - the correct definition would be the sequence is where the
auto_increment equivalent gets the next value. A straight conversion
would be replace auto_increment with DEFAULT nextval('this_table_seq')
after creating the sequence definition but these steps are automated by
using a data type of serial.

>> 3. Does this work in PostgreSQL:
>>
>> INSERT INTO table VALUES ('','y','z')
>>
>> where the empty first item is intended for an
>> auto_increment/SEQUENCE id field?
>
> No - this will try to stuff a string value (here, an empty string)
> into an integer column, which will cause an error.
>
> INSERT INTO table (fld_y, fld_z) VALUES ('y', 'z');

Another way is INSERT INTO table VALUES (NULL,'y','z')

--

Shane Ambler
pgSQL (at) Sheeky (dot) Biz

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