Re: Parent Id
От | Gene Vital |
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Тема | Re: Parent Id |
Дата | |
Msg-id | 3F85CE8D.3040500@karibe.com обсуждение исходный текст |
Ответ на | Re: Parent Id (Bruno Wolff III <bruno@wolff.to>) |
Ответы |
Re: Parent Id
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Список | pgsql-general |
ok, I am new to Postgres so could you give a little better explanation of this ?? I haven't created any sequence for this I am just using a type serial field. will I have to create a sequence for it? Here is my code to create the tables CREATE TABLE workstations (station_id INT4 PRIMARY KEY, name VARCHAR(50), description VARCHAR(250)) CREATE TABLE wsoptions (option_id SERIAL PRIMARY KEY, station_id INT4 REFERENCES workstations (station_id) ON DELETE CASCADE, type VARCHAR(20), data TEXT) insert into workstations (name, description) values("new", "This is a test") insert into wsoptions (stations_id, type, data) values( ????, "LOCATION", "10th floor outer, office 27") thanks.... Bruno Wolff III wrote: > On Thu, Oct 09, 2003 at 15:55:27 -0400, > Gene Vital <genevital@karibe.com> wrote: > >>have an example :) >> >>Bruno Wolff III wrote: >> >> >>>On Thu, Oct 09, 2003 at 14:26:21 -0400, >>> Gene Vital <genevital@karibe.com> wrote: >>> >>> >>>>when inserting new records into parent / child tables, what is the best >>>>recommended way of retrieving the pkey value from the parent table when >>>>using auto incrementing fields ? >>> >>> >>>You want to use currval. currval will return the last value obtained >>>by nextval in the same session, so it is safe to use without any additional >>>locking. >>> > > > You would do something like: > insert into parent_table (pk, col1, col2) values (default, 'val1', 'val2'); > insert into child_table (pk, parent, col1, col2) > values (default, currval('parent_table_pk_seq'), 'val3', 'val4'); > > I don't remember when being able to use default in insert statements was > added. You may need to just leave the pk columns off the list. I added them > so that you could see what the normal sequence name looks like. I also > assume that the two pk columns are declared to be of type serial. If not, > then you have to do the sequence and default creation yourself. > -- Eugene Vital Any technology indistinguishable from magic is insufficiently advanced.
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