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Add casts from int4 and int8 to numeric.

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Joey Adams, per gripe from Ramanujam.  Review by myself and Tom Lane.
This commit is contained in:
Robert Haas 2011-04-05 09:35:43 -04:00
parent 88f32b7ca2
commit f5e524d92b
8 changed files with 161 additions and 7 deletions
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17
doc/src/sgml/datatype.sgml
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@ -886,15 +886,22 @@ ALTER SEQUENCE <replaceable class="parameter">tablename</replaceable>_<replaceab
</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:
Values of the <type>numeric</type>, <type>int</type>, and
<type>bigint</type> data types can be cast to <type>money</type>.
Conversion from the <type>real</type> and <type>double precision</type>
data types can be done by casting to <type>numeric</type> first, for
example:
<programlisting>
SELECT 1234::numeric::money;
SELECT '12.34'::float8::numeric::money;
</programlisting>
However, this is not recommended. Floating point numbers should not be
used to handle money due to the potential for rounding errors.
</para>
<para>
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:
precision, and must also be done in two stages:
<programlisting>
SELECT '52093.89'::money::numeric::float8;
</programlisting>

62
src/backend/utils/adt/cash.c
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@ -26,6 +26,7 @@
#include "libpq/pqformat.h"
#include "utils/builtins.h"
#include "utils/cash.h"
#include "utils/int8.h"
#include "utils/numeric.h"
#include "utils/pg_locale.h"
@ -92,7 +93,6 @@ num_word(Cash value)
return buf;
} /* num_word() */
/* cash_in()
* Convert a string to a cash data type.
* Format is [$]###[,]###[.##]
@ -938,3 +938,63 @@ numeric_cash(PG_FUNCTION_ARGS)
PG_RETURN_CASH(result);
}
/* int4_cash()
* Convert int4 (int) to cash
*/
Datum
int4_cash(PG_FUNCTION_ARGS)
{
int32 amount = PG_GETARG_INT32(0);
Cash result;
int fpoint;
int64 scale;
int i;
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;
/* compute amount * scale, checking for overflow */
result = DatumGetInt64(DirectFunctionCall2(int8mul, Int64GetDatum(amount),
Int64GetDatum(scale)));
PG_RETURN_CASH(result);
}
/* int8_cash()
* Convert int8 (bigint) to cash
*/
Datum
int8_cash(PG_FUNCTION_ARGS)
{
int64 amount = PG_GETARG_INT64(0);
Cash result;
int fpoint;
int64 scale;
int i;
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;
/* compute amount * scale, checking for overflow */
result = DatumGetInt64(DirectFunctionCall2(int8mul, Int64GetDatum(amount),
Int64GetDatum(scale)));
PG_RETURN_CASH(result);
}

2
src/include/catalog/catversion.h
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@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 201103201
#define CATALOG_VERSION_NO 201104051
#endif

2
src/include/catalog/pg_cast.h
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@ -126,6 +126,8 @@ 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 ));
DATA(insert ( 23 790 3811 a f ));
DATA(insert ( 20 790 3812 a f ));
/* Allow explicit coercions between int4 and bool */
DATA(insert ( 23 16 2557 e f ));

4
src/include/catalog/pg_proc.h
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@ -971,6 +971,10 @@ DATA(insert OID = 3823 ( numeric PGNSP PGUID 12 1 0 0 f f f t f s 1 0 1700
DESCR("convert money to numeric");
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("convert numeric to money");
DATA(insert OID = 3811 ( money PGNSP PGUID 12 1 0 0 f f f t f s 1 0 790 "23" _null_ _null_ _null_ _null_ int4_cash _null_ _null_ _null_ ));
DESCR("convert int4 to money");
DATA(insert OID = 3812 ( money PGNSP PGUID 12 1 0 0 f f f t f s 1 0 790 "20" _null_ _null_ _null_ _null_ int8_cash _null_ _null_ _null_ ));
DESCR("convert int8 to money");
/* OIDS 900 - 999 */

3
src/include/utils/cash.h
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@ -67,4 +67,7 @@ extern Datum cash_words(PG_FUNCTION_ARGS);
extern Datum cash_numeric(PG_FUNCTION_ARGS);
extern Datum numeric_cash(PG_FUNCTION_ARGS);
extern Datum int4_cash(PG_FUNCTION_ARGS);
extern Datum int8_cash(PG_FUNCTION_ARGS);
#endif /* CASH_H */

63
src/test/regress/expected/money.out
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@ -185,3 +185,66 @@ SELECT * FROM money_data;
$123.46
(1 row)
-- Cast int4/int8 to money
SELECT 1234567890::money;
money
-------------------
$1,234,567,890.00
(1 row)
SELECT 12345678901234567::money;
money
----------------------------
$12,345,678,901,234,567.00
(1 row)
SELECT 123456789012345678::money;
ERROR: bigint out of range
SELECT 9223372036854775807::money;
ERROR: bigint out of range
SELECT (-12345)::money;
money
-------------
-$12,345.00
(1 row)
SELECT (-1234567890)::money;
money
--------------------
-$1,234,567,890.00
(1 row)
SELECT (-12345678901234567)::money;
money
-----------------------------
-$12,345,678,901,234,567.00
(1 row)
SELECT (-123456789012345678)::money;
ERROR: bigint out of range
SELECT (-9223372036854775808)::money;
ERROR: bigint out of range
SELECT 1234567890::int4::money;
money
-------------------
$1,234,567,890.00
(1 row)
SELECT 12345678901234567::int8::money;
money
----------------------------
$12,345,678,901,234,567.00
(1 row)
SELECT (-1234567890)::int4::money;
money
--------------------
-$1,234,567,890.00
(1 row)
SELECT (-12345678901234567)::int8::money;
money
-----------------------------
-$12,345,678,901,234,567.00
(1 row)

15
src/test/regress/sql/money.sql
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@ -56,3 +56,18 @@ SELECT * FROM money_data;
DELETE FROM money_data;
INSERT INTO money_data VALUES ('$123.459');
SELECT * FROM money_data;
-- Cast int4/int8 to money
SELECT 1234567890::money;
SELECT 12345678901234567::money;
SELECT 123456789012345678::money;
SELECT 9223372036854775807::money;
SELECT (-12345)::money;
SELECT (-1234567890)::money;
SELECT (-12345678901234567)::money;
SELECT (-123456789012345678)::money;
SELECT (-9223372036854775808)::money;
SELECT 1234567890::int4::money;
SELECT 12345678901234567::int8::money;
SELECT (-1234567890)::int4::money;
SELECT (-12345678901234567)::int8::money;