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* Questions on Virtual Attributes
@ 1994-10-01 23:38 WEIX%PTHWRK.allin1@puget.com
1994-10-02 19:34 ` Re: Questions on Virtual Attributes Paul M. Aoki <aoki@cs.berkeley.edu>
0 siblings, 1 reply; 3+ messages in thread
From: WEIX%PTHWRK.allin1@puget.com @ 1994-10-01 23:38 UTC (permalink / raw)
To: legacy
From: NAME: Xinguo Wei
FUNC:
TEL: <WEIX AT A1 AT PTHWRK>
To: smtp%"postgres@postgres.berkeley.edu"@mrgate
Hi,
I am testing the virtual attribute function using the SET expression and I have
two questions here.
1. When define the attribute using X = setof Y, the keyword "setof" seems not
necessary if Y is a class name, i.e., "members = EMP" is the same as "members =
setof EMP". If Y is not a class name, then "setof" is needed. Am I right?
2. In the following test case, I defined a set attribute for DEPT. But I
couldn't find the way to retrive its value!! Please help me.
create EMP (name = text, dept = text)\g
create DEPT (name = text, emp_no = setof int4) \g
append EMP (name = "a", dept = "candy")\g
append EMP (name = "b", dept = "candy")\g
append DEPT (name = "candy",
EMP_no = "retrieve (a = count{EMP.name where EMP.dept = \\"candy\\"})") \g
retrieve (DEPT.name, DEPT.emp_no) \g
Query sent to backend is "retrieve (dept.name, dept.emp_no) "
-----------------------------
| name | emp_no |
-----------------------------
| candy | 25252 |
-----------------------------
The value of emp_no here looks like an OID. What kind of object is that? How
can i get the correct value of 2 ?
Thanks!!
Xinguo Wei
weix@puget.com
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^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: Questions on Virtual Attributes
1994-10-01 23:38 Questions on Virtual Attributes WEIX%PTHWRK.allin1@puget.com
@ 1994-10-02 19:34 ` Paul M. Aoki <aoki@cs.berkeley.edu>
0 siblings, 0 replies; 3+ messages in thread
From: Paul M. Aoki @ 1994-10-02 19:34 UTC (permalink / raw)
To: WEIX%PTHWRK.allin1@puget.com; +Cc: legacy
"WEIX%PTHWRK.allin1"@puget.com writes:
> create EMP (name = text, dept = text)\g
> create DEPT (name = text, emp_no = setof int4) \g
create FOO (a = int4) \g
create DEPT (name = text, emp_no = setof FOO) \g
> append EMP (name = "a", dept = "candy")\g
> append EMP (name = "b", dept = "candy")\g
> append DEPT (name = "candy",
> emp_no = "retrieve (a = count{EMP.name where EMP.dept = \\"candy\\"})") \g
> retrieve (DEPT.name, DEPT.emp_no) \g
> Query sent to backend is "retrieve (dept.name, dept.emp_no) "
> -----------------------------
> | name | emp_no |
> -----------------------------
> | candy | 25252 |
> -----------------------------
> The value of emp_no here looks like an OID. What kind of object is that? How
> can i get the correct value of 2 ?
by dereferencing it. the only thing you can do with a set is project
an attribute from it.
* retrieve (DEPT.name, DEPT.emp_no.a)\g
Query sent to backend is "retrieve (DEPT.name, DEPT.emp_no.a)"
-----------------------------
| name | a |
-----------------------------
| candy | 2 |
-----------------------------
Go
*
--
Paul M. Aoki | University of California at Berkeley
aoki@CS.Berkeley.EDU | Dept. of EECS, Computer Science Division (#1776)
| Berkeley, CA 94720-1776
==============================================================================
To add/remove yourself to/from the POSTGRES mailing list: send mail with
the subject line ADD or DEL to "postgres-request@postgres.Berkeley.EDU"
If this fails, send mail to "post_questions@postgres.Berkeley.EDU" and
a human will deal with it. DO NOT post to the "postgres" mailing list.
==============================================================================
^ permalink raw reply [nested|flat] 3+ messages in thread
* Questions on Virtual Attributes....
@ 1994-10-03 15:36 WEIX%PTHWRK.allin1@puget.com
0 siblings, 0 replies; 3+ messages in thread
From: WEIX%PTHWRK.allin1@puget.com @ 1994-10-03 15:36 UTC (permalink / raw)
To: legacy
From: NAME: Xinguo Wei
FUNC:
TEL: <WEIX AT A1 AT PTHWRK>
To: smtp%"postgres@nobozo.CS.Berkeley.EDU"@mrgate
Hi,
I am testing the virtual attribute function using the SET expression and I have
two questions here.
1. When define the attribute using X = setof Y, the keyword "setof" seems not
necessary if Y is a class name, i.e., "members = EMP" is the same as "members =
setof EMP". If Y is not a class name, then "setof" is needed. Am I right?
2. In the following test case, I defined a set attribute for DEPT. But I
couldn't find the way to retrive its value!! Please help me.
create EMP (name = text, dept = text)\g
create DEPT (name = text, emp_no = setof int4) \g
append EMP (name = "a", dept = "candy")\g
append EMP (name = "b", dept = "candy")\g
append DEPT (name = "candy",
EMP_no = "retrieve (a = count{EMP.name where EMP.dept = \\"candy\\"})") \g
retrieve (DEPT.name, DEPT.emp_no) \g
Query sent to backend is "retrieve (dept.name, dept.emp_no) "
-----------------------------
| name | emp_no |
-----------------------------
| candy | 25252 |
-----------------------------
The value of emp_no here looks like an OID. What kind of object is that? How
can i get the correct value of 2 ?
Thanks!!
Xinguo Wei
weix@puget.com
==============================================================================
To add/remove yourself to/from the POSTGRES mailing list: send mail with
the subject line ADD or DEL to "postgres-request@postgres.Berkeley.EDU"
If this fails, send mail to "post_questions@postgres.Berkeley.EDU" and
a human will deal with it. DO NOT post to the "postgres" mailing list.
==============================================================================
^ permalink raw reply [nested|flat] 3+ messages in thread
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1994-10-01 23:38 Questions on Virtual Attributes WEIX%PTHWRK.allin1@puget.com
1994-10-02 19:34 ` Paul M. Aoki <aoki@cs.berkeley.edu>
1994-10-03 15:36 Questions on Virtual Attributes.... WEIX%PTHWRK.allin1@puget.com
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