Re: Creating Primary Key after CREATE TABLE: Is Sequence created?

mdr wrote
> I had a question on creating PK with alter table, after table is created. 
> 
> I understand I create a PK id during create table by stating id as
> follows:
> id serial primary key
> 
> It implicitly creates index and the sequence testing_id_seq to be
> associated with the id field.
> I can list the sequence with \ds.

"PRIMARY KEY" implicitly creates an index
"serial" (i.e., the column type) implicitly creates a sequence (of type
integer; bigserial creates a biginteger sequence)

psuedo-sql:

CREATE TABLE a (id serial);  ALTER TABLE a ADD CONSTRAINT PRIMARY KEY (id);

The first creates the serial; the second creates the index and unique
constraint.  Should be equivalent to:  

CREATE TABLE a (id serial PRIMARY KEY);

David J.








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