Re: optional reference - Mailing list pgsql-novice

From Pushpendra Singh Thakur
Subject Re: optional reference
Date
Msg-id d6a413081001240200p34710c25w30683c53fbf14049@mail.gmail.com
Whole thread Raw
In response to optional reference  (bill house <wchouse@bellsouth.net>)
Responses Re: optional reference  (Mark Kelly <pgsql@wastedtimes.net>)
List 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

pgsql-novice by date:

Previous
From: Rikard Bosnjakovic
Date:
Subject: Comparing times to "now + 45 seconds"
Next
From: "Jean-Yves F. Barbier"
Date:
Subject: Re: Comparing times to "now + 45 seconds"