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Add support for dividing money by money (yielding a float8 result) and for

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casting between money and numeric.

Andy Balholm, reviewed by Kevin Grittner
This commit is contained in:
Tom Lane 2010-07-16 02:15:56 +00:00
parent e11cfa87be
commit 7590ddb3eb
7 changed files with 148 additions and 34 deletions
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54
doc/src/sgml/datatype.sgml
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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.250 2010/07/03 04:03:06 tgl Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.251 2010/07/16 02:15:53 tgl Exp $ -->
<chapter id="datatype">
<title>Data Types</title>
@ -839,32 +839,11 @@ ALTER SEQUENCE <replaceable class="parameter">tablename</replaceable>_<replaceab
fractional precision; see <xref
linkend="datatype-money-table">. The fractional precision is
determined by the database's <xref linkend="guc-lc-monetary"> setting.
The range shown in the table assumes there are two fractional digits.
Input is accepted in a variety of formats, including integer and
floating-point literals, as well as typical
currency formatting, such as <literal>'$1,000.00'</literal>.
Output is generally in the latter form but depends on the locale.
Non-quoted numeric values can be converted to <type>money</type> by
casting the numeric value to <type>text</type> and then
<type>money</type>, for example:
<programlisting>
SELECT 1234::text::money;
</programlisting>
There is no simple way of doing the reverse in a locale-independent
manner, namely casting a <type>money</type> value to a numeric type.
If you know the currency symbol and thousands separator you can use
<function>regexp_replace()</>:
<programlisting>
SELECT regexp_replace('52093.89'::money::text, '[$,]', '', 'g')::numeric;
</programlisting>
</para>
<para>
Since the output of this data type is locale-sensitive, it might not
work to load <type>money</> data into a database that has a different
setting of <varname>lc_monetary</>. To avoid problems, before
restoring a dump into a new database make sure <varname>lc_monetary</> has the same or
equivalent value as in the database that was dumped.
</para>
<table id="datatype-money-table">
@ -888,6 +867,35 @@ SELECT regexp_replace('52093.89'::money::text, '[$,]', '', 'g')::numeric;
</tbody>
</tgroup>
</table>
<para>
Since the output of this data type is locale-sensitive, it might not
work to load <type>money</> data into a database that has a different
setting of <varname>lc_monetary</>. To avoid problems, before
restoring a dump into a new database make sure <varname>lc_monetary</> has
the same or equivalent value as in the database that was dumped.
</para>
<para>
Values of the <type>numeric</type> data type can be cast to
<type>money</type>. Other numeric types can be converted to
<type>money</type> by casting to <type>numeric</type> first, for example:
<programlisting>
SELECT 1234::numeric::money;
</programlisting>
A <type>money</type> value can be cast to <type>numeric</type> without
loss of precision. Conversion to other types could potentially lose
precision, and it must be done in two stages, for example:
<programlisting>
SELECT '52093.89'::money::numeric::float8;
</programlisting>
</para>
<para>
When a <type>money</type> value is divided by another <type>money</type>
value, the result is <type>double precision</type> (i.e., a pure number,
not money); the currency units cancel each other out in the division.
</para>
</sect1>

99
src/backend/utils/adt/cash.c
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@ -13,7 +13,7 @@
* this version handles 64 bit numbers and so can hold values up to
* $92,233,720,368,547,758.07.
*
* $PostgreSQL: pgsql/src/backend/utils/adt/cash.c,v 1.82 2009/06/11 14:49:03 momjian Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/cash.c,v 1.83 2010/07/16 02:15:53 tgl Exp $
*/
#include "postgres.h"
@ -26,6 +26,7 @@
#include "libpq/pqformat.h"
#include "utils/builtins.h"
#include "utils/cash.h"
#include "utils/numeric.h"
#include "utils/pg_locale.h"
#define CASH_BUFSZ 36
@ -114,7 +115,6 @@ cash_in(PG_FUNCTION_ARGS)
psymbol;
const char *nsymbol,
*csymbol;
struct lconv *lconvert = PGLC_localeconv();
/*
@ -263,7 +263,6 @@ cash_out(PG_FUNCTION_ARGS)
*nsymbol;
char dsymbol;
char convention;
struct lconv *lconvert = PGLC_localeconv();
/* see comments about frac_digits in cash_in() */
@ -478,6 +477,26 @@ cash_mi(PG_FUNCTION_ARGS)
}
/* cash_div_cash()
* Divide cash by cash, returning float8.
*/
Datum
cash_div_cash(PG_FUNCTION_ARGS)
{
Cash dividend = PG_GETARG_CASH(0);
Cash divisor = PG_GETARG_CASH(1);
float8 quotient;
if (divisor == 0)
ereport(ERROR,
(errcode(ERRCODE_DIVISION_BY_ZERO),
errmsg("division by zero")));
quotient = (float8) dividend / (float8) divisor;
PG_RETURN_FLOAT8(quotient);
}
/* cash_mul_flt8()
* Multiply cash by float8.
*/
@ -845,3 +864,77 @@ cash_words(PG_FUNCTION_ARGS)
/* return as text datum */
PG_RETURN_TEXT_P(cstring_to_text(buf));
}
/* cash_numeric()
* Convert cash to numeric.
*/
Datum
cash_numeric(PG_FUNCTION_ARGS)
{
Cash money = PG_GETARG_CASH(0);
Numeric result;
int fpoint;
int64 scale;
int i;
Datum amount;
Datum numeric_scale;
Datum quotient;
struct lconv *lconvert = PGLC_localeconv();
/* see comments about frac_digits in cash_in() */
fpoint = lconvert->frac_digits;
if (fpoint < 0 || fpoint > 10)
fpoint = 2;
/* compute required scale factor */
scale = 1;
for (i = 0; i < fpoint; i++)
scale *= 10;
/* form the result as money / scale */
amount = DirectFunctionCall1(int8_numeric, Int64GetDatum(money));
numeric_scale = DirectFunctionCall1(int8_numeric, Int64GetDatum(scale));
quotient = DirectFunctionCall2(numeric_div, amount, numeric_scale);
/* forcibly round to exactly the intended number of digits */
result = DatumGetNumeric(DirectFunctionCall2(numeric_round,
quotient,
Int32GetDatum(fpoint)));
PG_RETURN_NUMERIC(result);
}
/* numeric_cash()
* Convert numeric to cash.
*/
Datum
numeric_cash(PG_FUNCTION_ARGS)
{
Datum amount = PG_GETARG_DATUM(0);
Cash result;
int fpoint;
int64 scale;
int i;
Datum numeric_scale;
struct lconv *lconvert = PGLC_localeconv();
/* see comments about frac_digits in cash_in() */
fpoint = lconvert->frac_digits;
if (fpoint < 0 || fpoint > 10)
fpoint = 2;
/* compute required scale factor */
scale = 1;
for (i = 0; i < fpoint; i++)
scale *= 10;
/* multiply the input amount by scale factor */
numeric_scale = DirectFunctionCall1(int8_numeric, Int64GetDatum(scale));
amount = DirectFunctionCall2(numeric_mul, amount, numeric_scale);
/* note that numeric_int8 will round to nearest integer for us */
result = DatumGetInt64(DirectFunctionCall1(numeric_int8, amount));
PG_RETURN_CASH(result);
}

4
src/include/catalog/catversion.h
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@ -37,7 +37,7 @@
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.587 2010/04/26 14:22:37 momjian Exp $
* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.588 2010/07/16 02:15:54 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 201004261
#define CATALOG_VERSION_NO 201007151
#endif

4
src/include/catalog/pg_cast.h
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@ -10,7 +10,7 @@
*
* Copyright (c) 2002-2010, PostgreSQL Global Development Group
*
* $PostgreSQL: pgsql/src/include/catalog/pg_cast.h,v 1.44 2010/01/05 01:06:56 tgl Exp $
* $PostgreSQL: pgsql/src/include/catalog/pg_cast.h,v 1.45 2010/07/16 02:15:54 tgl Exp $
*
* NOTES
* the genbki.pl script reads this file and generates .bki
@ -124,6 +124,8 @@ DATA(insert ( 1700 21 1783 a f ));
DATA(insert ( 1700 23 1744 a f ));
DATA(insert ( 1700 700 1745 i f ));
DATA(insert ( 1700 701 1746 i f ));
DATA(insert ( 790 1700 3823 a f ));
DATA(insert ( 1700 790 3824 a f ));
/* Allow explicit coercions between int4 and bool */
DATA(insert ( 23 16 2557 e f ));

3
src/include/catalog/pg_operator.h
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@ -8,7 +8,7 @@
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/catalog/pg_operator.h,v 1.170 2010/01/14 16:31:09 teodor Exp $
* $PostgreSQL: pgsql/src/include/catalog/pg_operator.h,v 1.171 2010/07/16 02:15:54 tgl Exp $
*
* NOTES
* the genbki.pl script reads this file and generates .bki
@ -415,6 +415,7 @@ DATA(insert OID = 915 ( "/" PGNSP PGUID b f f 790 21 790 0 0 cash_div_
DATA(insert OID = 916 ( "*" PGNSP PGUID b f f 701 790 790 908 0 flt8_mul_cash - - ));
DATA(insert OID = 917 ( "*" PGNSP PGUID b f f 23 790 790 912 0 int4_mul_cash - - ));
DATA(insert OID = 918 ( "*" PGNSP PGUID b f f 21 790 790 914 0 int2_mul_cash - - ));
DATA(insert OID = 3825 ( "/" PGNSP PGUID b f f 790 790 701 0 0 cash_div_cash - - ));
DATA(insert OID = 965 ( "^" PGNSP PGUID b f f 701 701 701 0 0 dpow - - ));
DATA(insert OID = 966 ( "+" PGNSP PGUID b f f 1034 1033 1034 0 0 aclinsert - - ));

12
src/include/catalog/pg_proc.h
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@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.571 2010/05/27 16:20:11 tgl Exp $
* $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.572 2010/07/16 02:15:54 tgl Exp $
*
* NOTES
* The script catalog/genbki.pl reads this file and generates .bki
@ -1165,9 +1165,9 @@ DESCR("multiply");
DATA(insert OID = 867 ( cash_div_int2 PGNSP PGUID 12 1 0 0 f f f t f i 2 0 790 "790 21" _null_ _null_ _null_ _null_ cash_div_int2 _null_ _null_ _null_ ));
DESCR("divide");
DATA(insert OID = 886 ( cash_in PGNSP PGUID 12 1 0 0 f f f t f i 1 0 790 "2275" _null_ _null_ _null_ _null_ cash_in _null_ _null_ _null_ ));
DATA(insert OID = 886 ( cash_in PGNSP PGUID 12 1 0 0 f f f t f s 1 0 790 "2275" _null_ _null_ _null_ _null_ cash_in _null_ _null_ _null_ ));
DESCR("I/O");
DATA(insert OID = 887 ( cash_out PGNSP PGUID 12 1 0 0 f f f t f i 1 0 2275 "790" _null_ _null_ _null_ _null_ cash_out _null_ _null_ _null_ ));
DATA(insert OID = 887 ( cash_out PGNSP PGUID 12 1 0 0 f f f t f s 1 0 2275 "790" _null_ _null_ _null_ _null_ cash_out _null_ _null_ _null_ ));
DESCR("I/O");
DATA(insert OID = 888 ( cash_eq PGNSP PGUID 12 1 0 0 f f f t f i 2 0 16 "790 790" _null_ _null_ _null_ _null_ cash_eq _null_ _null_ _null_ ));
DESCR("equal");
@ -1197,6 +1197,12 @@ DATA(insert OID = 919 ( flt8_mul_cash PGNSP PGUID 12 1 0 0 f f f t f i 2 0
DESCR("multiply");
DATA(insert OID = 935 ( cash_words PGNSP PGUID 12 1 0 0 f f f t f i 1 0 25 "790" _null_ _null_ _null_ _null_ cash_words _null_ _null_ _null_ ));
DESCR("output amount as words");
DATA(insert OID = 3822 ( cash_div_cash PGNSP PGUID 12 1 0 0 f f f t f i 2 0 701 "790 790" _null_ _null_ _null_ _null_ cash_div_cash _null_ _null_ _null_ ));
DESCR("divide");
DATA(insert OID = 3823 ( numeric PGNSP PGUID 12 1 0 0 f f f t f s 1 0 1700 "790" _null_ _null_ _null_ _null_ cash_numeric _null_ _null_ _null_ ));
DESCR("(internal)");
DATA(insert OID = 3824 ( money PGNSP PGUID 12 1 0 0 f f f t f s 1 0 790 "1700" _null_ _null_ _null_ _null_ numeric_cash _null_ _null_ _null_ ));
DESCR("(internal)");
/* OIDS 900 - 999 */

6
src/include/utils/cash.h
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@ -1,5 +1,5 @@
/*
* $PostgreSQL: pgsql/src/include/utils/cash.h,v 1.27 2009/06/11 14:49:13 momjian Exp $
* $PostgreSQL: pgsql/src/include/utils/cash.h,v 1.28 2010/07/16 02:15:56 tgl Exp $
*
*
* cash.h
@ -37,6 +37,7 @@ extern Datum cash_cmp(PG_FUNCTION_ARGS);
extern Datum cash_pl(PG_FUNCTION_ARGS);
extern Datum cash_mi(PG_FUNCTION_ARGS);
extern Datum cash_div_cash(PG_FUNCTION_ARGS);
extern Datum cash_mul_flt8(PG_FUNCTION_ARGS);
extern Datum flt8_mul_cash(PG_FUNCTION_ARGS);
@ -63,4 +64,7 @@ extern Datum cashsmaller(PG_FUNCTION_ARGS);
extern Datum cash_words(PG_FUNCTION_ARGS);
extern Datum cash_numeric(PG_FUNCTION_ARGS);
extern Datum numeric_cash(PG_FUNCTION_ARGS);
#endif /* CASH_H */