My Object able solution.....??
От | alex@AvengerGear.com (Debian User) |
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Тема | My Object able solution.....?? |
Дата | |
Msg-id | 20020312085642.A3026@AvengerGear.com обсуждение исходный текст |
Ответы |
Re: My Object able solution.....??
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Список | pgsql-hackers |
Here is my short hack for the object reference ( tuple ) return as int4 function. Datum spycastoid(PG_FUNCTION_ARGS); Datum spycastoidbyname(PG_FUNCTION_ARGS); /* Composite types */ PG_FUNCTION_INFO_V1(spycastoid); Datum spycastoid(PG_FUNCTION_ARGS) { TupleTableSlot *t = (TupleTableSlot *) PG_GETARG_POINTER(0); int32 slot = PG_GETARG_INT32(1); int32 myid; bool isnull; myid = DatumGetInt32(GetAttributeByNum(t, slot, &isnull)); if (isnull) PG_RETURN_INT32(0); PG_RETURN_INT32(myid); } PG_FUNCTION_INFO_V1(spycastoidbyname); Datum spycastoidbyname(PG_FUNCTION_ARGS) { TupleTableSlot *t = (TupleTableSlot *) PG_GETARG_POINTER(0); text *slot = PG_GETARG_TEXT_P(1); int32 myid; bool isnull; /*printf( "cast -->%s<----", slot+VARHDRSZ );*/ myid = DatumGetInt32(GetAttributeByName(t, slot->vl_dat, &isnull)); if (isnull) PG_RETURN_INT32(0); PG_RETURN_INT32(myid); } ***************FUNCTION A****************************** CREATE FUNCTION spycastoid( table_has_other_object, int4) RETURNS int4 AS '/usr/lib/postgresql/lib/castfunc.so' LANGUAGE'c'; ***************FUNCTION A2****************************** CREATE FUNCTION castoid(table_has_other_object) RETURNS int4 AS 'select spycastoid($1, 1);' <---colnum LANGUAGE 'sql'; ***************FUNCTION B****************************** CREATE FUNCTION spycastoidbyname( table_has_other_object , text) RETURNS int4 AS '/usr/lib/postgresql/lib/castfunc.so' LANGUAGE'c'; ***************FUNCTION B2***************************** CREATE FUNCTION spycastoidbyname( table_has_other_object ) RETURNS int4 AS 'select spycastoidbyname( $1, \'colname\')' LANGUAGE'sql'; so now at lease you can do select * from child where spycastoid(child, 1)=178120 or preset A2 select * from child where spycastoid(child)=178120 select * from child where spycastoidbyname(child, 'myfather')=178120 or preset B2 select * from child where spycastoidbyname( child )=178120 There may be some bug in between. I'm not sure. When the tuple get by name, something the string compare is not correct. Let me know if that work. I really want to see some real object action in PostgreSQL I'm currently building a Java API for all database to enable object-relation mapping for rapid application development. Let me know if you want to talk about this also. Alex
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