There have been a couple of recent threads bemoaning our lack of clarity
about how references to composite values work, eg
https://www.postgresql.org/message-id/flat/20161029121906.15993.79158%40wrigleys.postgresql.org
https://www.postgresql.org/message-id/flat/CAGwx4BnDQZyJJpzom-UU15wh7s3DQE%3DChEdEDQ2%2Brd5S7S2UNA%40mail.gmail.com
(same instigator but distinct threads)
I suggested that we ought to try to consolidate information about this
in one place, and attached is a WIP patch to that end. Some notes:
* I'm not completely sold on either the new section's title or its
location; but I cannot find a better location.
* Some of the text is borrowed from section 36.4.3 "SQL Functions on
Composite Types", which should probably now be shortened in favor of
linking to this section, but I didn't do that yet. There may be more
places that should get merged in.
* I noticed that there is noplace in Part II that describes RETURNING
clauses as such; there's some material in 7.8.2 "Data-Modifying Statements
in WITH", but that really is assuming that you know what RETURNING does
already, and in any case it fails to explain the clause's use in
standalone statements. This seems like an, um, oversight.
Comments, objections, better ideas? Should this get back-patched?
regards, tom lane
diff --git a/doc/src/sgml/queries.sgml b/doc/src/sgml/queries.sgml
index 718262f..30d487f 100644
*** a/doc/src/sgml/queries.sgml
--- b/doc/src/sgml/queries.sgml
*** SELECT tbl1.a, tbl2.a, tbl1.b FROM ...
*** 1457,1463
SELECT tbl1.*, tbl2.a FROM ...
! (See also .)
--- 1457,1464
SELECT tbl1.*, tbl2.a FROM ...
! See for more about the *
! notation.
diff --git a/doc/src/sgml/rowtypes.sgml b/doc/src/sgml/rowtypes.sgml
index 605dc71..23600a3 100644
*** a/doc/src/sgml/rowtypes.sgml
--- b/doc/src/sgml/rowtypes.sgml
***
*** 19,25
column of a table can be declared to be of a composite type.
!
Declaration of Composite Types
--- 19,25
column of a table can be declared to be of a composite type.
!
Declaration of Composite Types
*** CREATE TABLE inventory_item (
*** 90,96
! Composite Value Input
composite type
--- 90,96
! Constructing Composite Values
composite type
*** CREATE TABLE inventory_item (
*** 101,108
To write a composite value as a literal constant, enclose the field
values within parentheses and separate them by commas. You can put double
quotes around any field value, and must do so if it contains commas or
!parentheses. (More details appear below.) Thus, the general format of a
!composite constant is the following:
'( val1 , val2 , ... )'
--- 101,109
To write a composite value as a literal constant, enclose the field
values within parentheses and separate them by commas. You can put double
quotes around any field value, and must do so if it contains commas or
!parentheses. (More details appear below.) Thus, the general format of
!a composite constant is the following:
'( val1 , val2 , ... )'
*** CREATE TABLE inventory_item (
*** 129,135
the generic type constants discussed in . The constant is initially
treated as a string and passed to the composite-type input conversion
!routine. An explicit type specification might be necessary.)
--- 130,137
the generic type constants discussed in . The constant is initially
treated as a string and passed to the composite-type input conversion
!routine. An explicit type specification might be necessary to tell
!which type to convert the constant to.)
*** ROW('fuzzy dice', 42, 1.99)
*** 143,149
ROW('', 42, NULL)
The ROW keyword is actually optional as long as you have more than one
! field in the expression, so these can simplify to:
('fuzzy dice', 42, 1.99)
('', 42, NULL)
--- 145,151
ROW('', 42, NULL)
The ROW keyword is actually optional as long as you have more than one
! field in the expression, so these can be simplified to:
('fuzzy dice', 42, 1.99)
('', 42, NULL)
*** ROW('', 42, NULL)
*** 153,159
!
Accessing Composite Types
--- 155,161
!
Accessing Composite Types
*** SELECT (my_func(...)).field FROM ...
*** 198,203
--- 200,210
Without the extra parentheses, this will generate a syntax error.
+
+
+ The special field name * means all
+ fields, as further explained in .
+
*** INSERT INTO mytab (complex_col.r, comple
*** 243,248
--- 250,447
+
+ Using Composite Types in Queries
+
+
+There are various special syntax rules and behaviors associated with
+comp
