Re: migrating numeric to serial from MSSQL to postgres

> I believe:
> IDENTITY(1, 1) just means "Primary Key" in M$SQL
> 

IDENTITY is not obligatory a primary key.  It's an auto-incremented column.
It might correspond to a PostgreSQL sequence.

[http://msdn.microsoft.com/library/default.asp?url=/library/en-us/tsqlref/ts
_ia-iz_3iex.asp]

> numeric 18,0 means a numeric field of zero decimal points.  Hence we are
> looking at a 18 byte integer.  bigint is not big enough, so probably
> should use the same in numeric 18,0 in postgres
> 

numeric[ (precision[ , scale] )], where precision refers to the maximum
total number of decimal digits that can be stored.  The default precision is
18, and for such a value the storage is of 9 bytes.

[http://msdn2.microsoft.com/en-us/library/ms187746.aspx]

Because it seems that a default value has been used here, I'd say that
Kenneth doesn't have any particular requirement, haven't you Kenneth?... :-)
An int or a bigint would be perhaps sufficient.  My two cents.


I don't know whether Kenneth requires migrating database structure only or
whether he needs to migrate data too.

When migrating data, Kenneth might want to define a sequence which start
value begins at the next value of its IDENTITY column (cf.
IDENT_SEED(my_table)).

[http://msdn.microsoft.com/library/default.asp?url=/library/en-us/tsqlref/ts
_ia-iz_9yxw.asp]

Kenneth might want to transfer his data first and to define the sequence
after (for transfer performance reason?):

CREATE TABLE my_table
( Id INTEGER NOT NULL, ...
);

[DTS process here]

CREATE SEQUENCE my_sequence INCREMENT BY 1 MINVALUE 1 NO MAXVALUE START WITH <IDENTITY current value + 1> CACHE 1 NO
CYCLE;

ALTER TABLE m_table ALTER COLUMN Id SET DEFAULT NEXTVAL('my_sequence');

Does that make sense?


--
Daniel