Re: optional reference

Поиск
Список
Период
Сортировка
От Pushpendra Singh Thakur
Тема Re: optional reference
Дата
Msg-id d6a413081001240200p34710c25w30683c53fbf14049@mail.gmail.com
обсуждение исходный текст
Ответ на optional reference  (bill house <wchouse@bellsouth.net>)
Ответы Re: optional reference
Список pgsql-novice
create a third table to store your relations only.
Relation table C
create table C(
a_col1 char(8) references a(column_1),
b_col1 char(8) references b(column_1))

Both the tables will be independent (a and b) i mean they will not have any direct relations. 
 
2010/1/24 bill house <wchouse@bellsouth.net>
Hello,

What is a technique to reference some (but not all) rows from table a to a row in table b?

For example:

---------------------------

DROP TABLE a;
DROP TABLE b;


CREATE TABLE a (
 column_1 character(8),
 column_2 character(2),
 column_3 character(40)
 );

INSERT INTO a VALUES
 ('20901234', '01', 'This is a the first row'),
 ('20901234', '01', 'This is the second row'),
 ('20901234', '01', 'This is the third row'),
 ('20901235', '01', 'This is the fourth row'),
 ('20901236', '01', 'This is the fifth row'),
 ('20901236', '01', 'This is the sixth row'),
 ('20901237', '01', 'This is the seventh row'),
 ('20901238', '01', 'This is the eighth row');

CREATE TABLE b (
 column_1 character(8),
 column_2 character(2),
 column_3 character(40),
 PRIMARY KEY (column_1, column_2)
 );

 INSERT INTO b VALUES
 ('20901234', '01', 'Footnote #1'),
 ('20901234', '02', 'other stuff'),
 ('20901237', '01', 'Footnote #2');

--------------------------------------

Table a rows 1, 2 & 3 should point to table b row 1.

Table a row 7 should point to table b row 3.

Any guidance would be appreciated.

Thanks,

Bill House




--
Sent via pgsql-novice mailing list (pgsql-novice@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-novice



--
Pushpendra Singh Thakur

COREEXPERTS Technologies Private Limited
Business Process Automation & IT Support Services
http://www.corexprts.com
Phone - 91-761-4070036
Fax - 91-761-4010530
SMS - 91-799-66554

В списке pgsql-novice по дате отправления:

Предыдущее
От: Rikard Bosnjakovic
Дата:
Сообщение: Comparing times to "now + 45 seconds"
Следующее
От: "Jean-Yves F. Barbier"
Дата:
Сообщение: Re: Comparing times to "now + 45 seconds"