diff options
Diffstat (limited to 'doc/src/sgml/xindex.sgml')
| -rw-r--r-- | doc/src/sgml/xindex.sgml | 102 |
1 files changed, 53 insertions, 49 deletions
diff --git a/doc/src/sgml/xindex.sgml b/doc/src/sgml/xindex.sgml index 84b2c9050a1..485b6c06a1e 100644 --- a/doc/src/sgml/xindex.sgml +++ b/doc/src/sgml/xindex.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/xindex.sgml,v 1.63 2008/05/16 16:31:01 tgl Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/xindex.sgml,v 1.64 2008/12/07 23:46:39 alvherre Exp $ --> <sect1 id="xindex"> <title>Interfacing Extensions To Indexes</title> @@ -499,8 +499,8 @@ reduces the odds of getting inconsistent results for corner cases. Following this approach, we first write: -<programlisting> -#define Mag(c) ((c)->x*(c)->x + (c)->y*(c)->y) +<programlisting><![CDATA[ +#define Mag(c) ((c)->x*(c)->x + (c)->y*(c)->y) static int complex_abs_cmp_internal(Complex *a, Complex *b) @@ -508,17 +508,18 @@ complex_abs_cmp_internal(Complex *a, Complex *b) double amag = Mag(a), bmag = Mag(b); - if (amag < bmag) + if (amag < bmag) return -1; - if (amag > bmag) + if (amag > bmag) return 1; return 0; } +]]> </programlisting> Now the less-than function looks like: -<programlisting> +<programlisting><![CDATA[ PG_FUNCTION_INFO_V1(complex_abs_lt); Datum @@ -527,8 +528,9 @@ complex_abs_lt(PG_FUNCTION_ARGS) Complex *a = (Complex *) PG_GETARG_POINTER(0); Complex *b = (Complex *) PG_GETARG_POINTER(1); - PG_RETURN_BOOL(complex_abs_cmp_internal(a, b) < 0); + PG_RETURN_BOOL(complex_abs_cmp_internal(a, b) < 0); } +]]> </programlisting> The other four functions differ only in how they compare the internal @@ -617,15 +619,16 @@ CREATE FUNCTION complex_abs_cmp(complex, complex) Now that we have the required operators and support routine, we can finally create the operator class: -<programlisting> +<programlisting><![CDATA[ CREATE OPERATOR CLASS complex_abs_ops DEFAULT FOR TYPE complex USING btree AS - OPERATOR 1 < , - OPERATOR 2 <= , + OPERATOR 1 < , + OPERATOR 2 <= , OPERATOR 3 = , - OPERATOR 4 >= , - OPERATOR 5 > , + OPERATOR 4 >= , + OPERATOR 5 > , FUNCTION 1 complex_abs_cmp(complex, complex); +]]> </programlisting> </para> @@ -708,87 +711,88 @@ CREATE OPERATOR CLASS complex_abs_ops on one of these types can be searched using a comparison value of another type. The family could be duplicated by these definitions: -<programlisting> +<programlisting><![CDATA[ CREATE OPERATOR FAMILY integer_ops USING btree; CREATE OPERATOR CLASS int8_ops DEFAULT FOR TYPE int8 USING btree FAMILY integer_ops AS -- standard int8 comparisons - OPERATOR 1 < , - OPERATOR 2 <= , + OPERATOR 1 < , + OPERATOR 2 <= , OPERATOR 3 = , - OPERATOR 4 >= , - OPERATOR 5 > , + OPERATOR 4 >= , + OPERATOR 5 > , FUNCTION 1 btint8cmp(int8, int8) ; CREATE OPERATOR CLASS int4_ops DEFAULT FOR TYPE int4 USING btree FAMILY integer_ops AS -- standard int4 comparisons - OPERATOR 1 < , - OPERATOR 2 <= , + OPERATOR 1 < , + OPERATOR 2 <= , OPERATOR 3 = , - OPERATOR 4 >= , - OPERATOR 5 > , + OPERATOR 4 >= , + OPERATOR 5 > , FUNCTION 1 btint4cmp(int4, int4) ; CREATE OPERATOR CLASS int2_ops DEFAULT FOR TYPE int2 USING btree FAMILY integer_ops AS -- standard int2 comparisons - OPERATOR 1 < , - OPERATOR 2 <= , + OPERATOR 1 < , + OPERATOR 2 <= , OPERATOR 3 = , - OPERATOR 4 >= , - OPERATOR 5 > , + OPERATOR 4 >= , + OPERATOR 5 > , FUNCTION 1 btint2cmp(int2, int2) ; ALTER OPERATOR FAMILY integer_ops USING btree ADD -- cross-type comparisons int8 vs int2 - OPERATOR 1 < (int8, int2) , - OPERATOR 2 <= (int8, int2) , + OPERATOR 1 < (int8, int2) , + OPERATOR 2 <= (int8, int2) , OPERATOR 3 = (int8, int2) , - OPERATOR 4 >= (int8, int2) , - OPERATOR 5 > (int8, int2) , + OPERATOR 4 >= (int8, int2) , + OPERATOR 5 > (int8, int2) , FUNCTION 1 btint82cmp(int8, int2) , -- cross-type comparisons int8 vs int4 - OPERATOR 1 < (int8, int4) , - OPERATOR 2 <= (int8, int4) , + OPERATOR 1 < (int8, int4) , + OPERATOR 2 <= (int8, int4) , OPERATOR 3 = (int8, int4) , - OPERATOR 4 >= (int8, int4) , - OPERATOR 5 > (int8, int4) , + OPERATOR 4 >= (int8, int4) , + OPERATOR 5 > (int8, int4) , FUNCTION 1 btint84cmp(int8, int4) , -- cross-type comparisons int4 vs int2 - OPERATOR 1 < (int4, int2) , - OPERATOR 2 <= (int4, int2) , + OPERATOR 1 < (int4, int2) , + OPERATOR 2 <= (int4, int2) , OPERATOR 3 = (int4, int2) , - OPERATOR 4 >= (int4, int2) , - OPERATOR 5 > (int4, int2) , + OPERATOR 4 >= (int4, int2) , + OPERATOR 5 > (int4, int2) , FUNCTION 1 btint42cmp(int4, int2) , -- cross-type comparisons int4 vs int8 - OPERATOR 1 < (int4, int8) , - OPERATOR 2 <= (int4, int8) , + OPERATOR 1 < (int4, int8) , + OPERATOR 2 <= (int4, int8) , OPERATOR 3 = (int4, int8) , - OPERATOR 4 >= (int4, int8) , - OPERATOR 5 > (int4, int8) , + OPERATOR 4 >= (int4, int8) , + OPERATOR 5 > (int4, int8) , FUNCTION 1 btint48cmp(int4, int8) , -- cross-type comparisons int2 vs int8 - OPERATOR 1 < (int2, int8) , - OPERATOR 2 <= (int2, int8) , + OPERATOR 1 < (int2, int8) , + OPERATOR 2 <= (int2, int8) , OPERATOR 3 = (int2, int8) , - OPERATOR 4 >= (int2, int8) , - OPERATOR 5 > (int2, int8) , + OPERATOR 4 >= (int2, int8) , + OPERATOR 5 > (int2, int8) , FUNCTION 1 btint28cmp(int2, int8) , -- cross-type comparisons int2 vs int4 - OPERATOR 1 < (int2, int4) , - OPERATOR 2 <= (int2, int4) , + OPERATOR 1 < (int2, int4) , + OPERATOR 2 <= (int2, int4) , OPERATOR 3 = (int2, int4) , - OPERATOR 4 >= (int2, int4) , - OPERATOR 5 > (int2, int4) , + OPERATOR 4 >= (int2, int4) , + OPERATOR 5 > (int2, int4) , FUNCTION 1 btint24cmp(int2, int4) ; +]]> </programlisting> Notice that this definition <quote>overloads</> the operator strategy and |