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array_length() function, and for SQL compatibility also cardinality()

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function as a special case.

This version still has the suspicious behavior of returning null for an
empty array (rather than zero), but this may need a wholesale revision of
empty array behavior, currently under discussion.

Jim Nasby, Robert Haas, Peter Eisentraut
REL8_5_ALPHA1_BRANCH
Peter Eisentraut 17 years ago
parent 4c22564471
commit f98f6ee064
8 changed files with 135 additions and 7 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 14
      doc/src/sgml/array.sgml
  2. 26
      doc/src/sgml/func.sgml
  3. 30
      src/backend/utils/adt/arrayfuncs.c
  4. 4
      src/include/catalog/catversion.h
  5. 6
      src/include/catalog/pg_proc.h
  6. 3
      src/include/utils/array.h
  7. 50
      src/test/regress/expected/arrays.out
  8. 9
      src/test/regress/sql/arrays.sql

14
doc/src/sgml/array.sgml
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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/array.sgml,v 1.67 2008/10/29 11:24:52 petere Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/array.sgml,v 1.68 2008/11/12 13:09:27 petere Exp $ -->
<sect1 id="arrays">
<title>Arrays</title>
@ -324,6 +324,18 @@ SELECT array_upper(schedule, 1) FROM sal_emp WHERE name = 'Carol';
-------------
2
(1 row)
</programlisting>
<function>array_length</function> will return the length of a specified
array dimension:
<programlisting>
SELECT array_length(schedule, 1) FROM sal_emp WHERE name = 'Carol';
array_length
--------------
2
(1 row)
</programlisting>
</para>
</sect2>

26
doc/src/sgml/func.sgml
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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.456 2008/11/07 22:54:41 tgl Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.457 2008/11/12 13:09:27 petere Exp $ -->
<chapter id="functions">
<title>Functions and Operators</title>
@ -9408,6 +9408,17 @@ SELECT NULLIF(value, '(none)') ...
<entry><literal>array_fill(7, ARRAY[3], ARRAY[2])</literal></entry>
<entry><literal>[2:4]={7,7,7}</literal></entry>
</row>
<row>
<entry>
<literal>
<function>array_length</function>(<type>anyarray</type>, <type>int</type>)
</literal>
</entry>
<entry><type>int</type></entry>
<entry>returns the length of the requested array dimension</entry>
<entry><literal>array_length(array[1,2,3], 1)</literal></entry>
<entry><literal>3</literal></entry>
</row>
<row>
<entry>
<literal>
@ -9452,6 +9463,19 @@ SELECT NULLIF(value, '(none)') ...
<entry><literal>array_upper(ARRAY[1,2,3,4], 1)</literal></entry>
<entry><literal>4</literal></entry>
</row>
<row>
<entry>
<literal>
<function>cardinality</function>(<type>anyarray</type>)
</literal>
</entry>
<entry><type>int</type></entry>
<entry>returns the length of the first dimension of the array
(special case of <function>array_length</function> for SQL
compatibility)</entry>
<entry><literal>cardinality(array[1,2,3])</literal></entry>
<entry><literal>3</literal></entry>
</row>
<row>
<entry>
<literal>

30
src/backend/utils/adt/arrayfuncs.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.148 2008/11/04 14:49:11 petere Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.149 2008/11/12 13:09:27 petere Exp $
*
*-------------------------------------------------------------------------
*/
@ -1640,6 +1640,34 @@ array_upper(PG_FUNCTION_ARGS)
PG_RETURN_INT32(result);
}
/*
* array_length :
* returns the length, of the dimension requested, for
* the array pointed to by "v", as an int4
*/
Datum
array_length(PG_FUNCTION_ARGS)
{
ArrayType *v = PG_GETARG_ARRAYTYPE_P(0);
int reqdim = PG_GETARG_INT32(1);
int *dimv;
int result;
/* Sanity check: does it look like an array at all? */
if (ARR_NDIM(v) <= 0 || ARR_NDIM(v) > MAXDIM)
PG_RETURN_NULL();
/* Sanity check: was the requested dim valid */
if (reqdim <= 0 || reqdim > ARR_NDIM(v))
PG_RETURN_NULL();
dimv = ARR_DIMS(v);
result = dimv[reqdim - 1];
PG_RETURN_INT32(result);
}
/*
* array_ref :
* This routine takes an array pointer and a subscript array and returns

4
src/include/catalog/catversion.h
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@ -37,7 +37,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.503 2008/11/09 21:24:33 tgl Exp $
* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.504 2008/11/12 13:09:27 petere Exp $
*
*-------------------------------------------------------------------------
*/
@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 200811091
#define CATALOG_VERSION_NO 200811121
#endif

6
src/include/catalog/pg_proc.h
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@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.524 2008/11/04 14:49:11 petere Exp $
* $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.525 2008/11/12 13:09:28 petere Exp $
*
* NOTES
* The script catalog/genbki.sh reads this file and generates .bki
@ -996,6 +996,10 @@ DATA(insert OID = 2091 ( array_lower PGNSP PGUID 12 1 0 0 f f t f i 2 23 "22
DESCR("array lower dimension");
DATA(insert OID = 2092 ( array_upper PGNSP PGUID 12 1 0 0 f f t f i 2 23 "2277 23" _null_ _null_ _null_ array_upper _null_ _null_ _null_ ));
DESCR("array upper dimension");
DATA(insert OID = 2176 ( array_length PGNSP PGUID 12 1 0 0 f f t f i 2 23 "2277 23" _null_ _null_ _null_ array_length _null_ _null_ _null_ ));
DESCR("array length");
DATA(insert OID = 2179 ( cardinality PGNSP PGUID 14 1 0 0 f f t f i 1 23 "2277" _null_ _null_ _null_ "select array_length($1, 1)" _null_ _null_ _null_ ));
DESCR("array length");
DATA(insert OID = 378 ( array_append PGNSP PGUID 12 1 0 0 f f f f i 2 2277 "2277 2283" _null_ _null_ _null_ array_push _null_ _null_ _null_ ));
DESCR("append element onto end of array");
DATA(insert OID = 379 ( array_prepend PGNSP PGUID 12 1 0 0 f f f f i 2 2277 "2283 2277" _null_ _null_ _null_ array_push _null_ _null_ _null_ ));

3
src/include/utils/array.h
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@ -49,7 +49,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/utils/array.h,v 1.69 2008/11/04 14:49:12 petere Exp $
* $PostgreSQL: pgsql/src/include/utils/array.h,v 1.70 2008/11/12 13:09:28 petere Exp $
*
*-------------------------------------------------------------------------
*/
@ -199,6 +199,7 @@ extern Datum array_ndims(PG_FUNCTION_ARGS);
extern Datum array_dims(PG_FUNCTION_ARGS);
extern Datum array_lower(PG_FUNCTION_ARGS);
extern Datum array_upper(PG_FUNCTION_ARGS);
extern Datum array_length(PG_FUNCTION_ARGS);
extern Datum array_larger(PG_FUNCTION_ARGS);
extern Datum array_smaller(PG_FUNCTION_ARGS);
extern Datum generate_subscripts(PG_FUNCTION_ARGS);

50
src/test/regress/expected/arrays.out
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@ -1075,3 +1075,53 @@ select array_to_string(string_to_array('1|2|3', '|'), '|');
1|2|3
(1 row)
select array_length(array[1,2,3], 1);
array_length
--------------
3
(1 row)
select array_length(array[[1,2,3], [4,5,6]], 0);
array_length
--------------
(1 row)
select array_length(array[[1,2,3], [4,5,6]], 1);
array_length
--------------
2
(1 row)
select array_length(array[[1,2,3], [4,5,6]], 2);
array_length
--------------
3
(1 row)
select array_length(array[[1,2,3], [4,5,6]], 3);
array_length
--------------
(1 row)
select cardinality(array[1,2,3]);
cardinality
-------------
3
(1 row)
select cardinality(array[[1,2,3], [4,5,6]]);
cardinality
-------------
2
(1 row)
select c, cardinality(c), d, cardinality(d) from arrtest;
c | cardinality | d | cardinality
-------------------+-------------+---------------+-------------
{} | | {} |
{foobar,new_word} | 2 | {{elt1,elt2}} | 1
{foo,new_word} | 2 | {bar,foo} | 2
(3 rows)

9
src/test/regress/sql/arrays.sql
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@ -386,3 +386,12 @@ select string_to_array('1|2|3', NULL);
select string_to_array(NULL, '|');
select array_to_string(string_to_array('1|2|3', '|'), '|');
select array_length(array[1,2,3], 1);
select array_length(array[[1,2,3], [4,5,6]], 0);
select array_length(array[[1,2,3], [4,5,6]], 1);
select array_length(array[[1,2,3], [4,5,6]], 2);
select array_length(array[[1,2,3], [4,5,6]], 3);
select cardinality(array[1,2,3]);
select cardinality(array[[1,2,3], [4,5,6]]);
select c, cardinality(c), d, cardinality(d) from arrtest;

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