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Attached is an update to contrib/dblink. Please apply if there are no

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objections.

Major changes:
   - removed cursor wrap around input sql to allow for remote
     execution of INSERT/UPDATE/DELETE
   - dblink now returns a resource id instead of a real pointer
   - added several utility functions

I'm still hoping to add explicit cursor open/fetch/close support before
7.3 is released, but I need a bit more time on that.

On a somewhat unrelated topic, I never got any feedback on the
unknownin/out patch and the mb_substring patch. Is there anything else I
need to do to get those applied?

Joe Conway
This commit is contained in:
Bruce Momjian 2002-04-24 02:28:28 +00:00
parent 30571b5496
commit 3bf6b8f06a
4 changed files with 1624 additions and 122 deletions

301
contrib/dblink/README.dblink

@ -3,7 +3,8 @@
* *
* Functions returning results from a remote database * Functions returning results from a remote database
* *
* Copyright (c) Joseph Conway <joe.conway@mail.com>, 2001; * Copyright (c) Joseph Conway <mail@joeconway.com>, 2001, 2002,
* ALL RIGHTS RESERVED;
* *
* Permission to use, copy, modify, and distribute this software and its * Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose, without fee, and without a written agreement * documentation for any purpose, without fee, and without a written agreement
@ -25,12 +26,19 @@
*/ */
Version 0.3 (14 June, 2001): Version 0.4 (7 April, 2002):
Function to test returning data set from remote database Functions allowing remote database INSERT/UPDATE/DELETE/SELECT, and
Tested under Linux (Red Hat 6.2 and 7.0) and PostgreSQL 7.1 and 7.2devel various utility functions.
Tested under Linux (Red Hat 7.2) and PostgreSQL 7.2 and 7.3devel
Release Notes: Release Notes:
Version 0.4
- removed cursor wrap around input sql to allow for remote
execution of INSERT/UPDATE/DELETE
- dblink now returns a resource id instead of a real pointer
- added several utility functions -- see below
Version 0.3 Version 0.3
- fixed dblink invalid pointer causing corrupt elog message - fixed dblink invalid pointer causing corrupt elog message
- fixed dblink_tok improper handling of null results - fixed dblink_tok improper handling of null results
@ -51,14 +59,36 @@ Installation:
installs following functions into database template1: installs following functions into database template1:
dblink() - returns a pointer to results from remote query dblink(text,text) RETURNS setof int
dblink_tok() - extracts and returns individual field results - returns a resource id for results from remote query
dblink_tok(int,int) RETURNS text
- extracts and returns individual field results
dblink_strtok(text,text,int) RETURNS text
- extracts and returns individual token from delimited text
dblink_get_pkey(name) RETURNS setof text
- returns the field names of a relation's primary key fields
dblink_last_oid(int) RETURNS oid
- returns the last inserted oid
dblink_build_sql_insert(name,int2vector,int2,_text,_text) RETURNS text
- builds an insert statement using a local tuple, replacing the
selection key field values with alternate supplied values
dblink_build_sql_delete(name,int2vector,int2,_text) RETURNS text
- builds a delete statement using supplied values for selection
key field values
dblink_build_sql_update(name,int2vector,int2,_text,_text) RETURNS text
- builds an update statement using a local tuple, replacing the
selection key field values with alternate supplied values
dblink_current_query() RETURNS text
- returns the current query string
dblink_replace(text,text,text) RETURNS text
- replace all occurences of substring-a in the input-string
with substring-b
Documentation Documentation
================================================================== ==================================================================
Name Name
dblink -- Returns a pointer to a data set from a remote database dblink -- Returns a resource id for a data set from a remote database
Synopsis Synopsis
@ -78,7 +108,7 @@ Inputs
Outputs Outputs
Returns setof int (pointer) Returns setof int (res_id)
Example usage Example usage
@ -94,13 +124,13 @@ dblink_tok -- Returns individual select field results from a dblink remote query
Synopsis Synopsis
dblink_tok(int pointer, int fnumber) dblink_tok(int res_id, int fnumber)
Inputs Inputs
pointer res_id
a pointer returned by a call to dblink() a resource id returned by a call to dblink()
fnumber fnumber
@ -131,6 +161,255 @@ Then you can simply write:
select f1, f2 from myremotetable where f1 like 'bytea%'; select f1, f2 from myremotetable where f1 like 'bytea%';
================================================================== ==================================================================
Name
dblink_strtok -- Extracts and returns individual token from delimited text
Synopsis
dblink_strtok(text inputstring, text delimiter, int posn) RETURNS text
Inputs
inputstring
any string you want to parse a token out of;
e.g. 'f=1&g=3&h=4'
delimiter
a single character to use as the delimiter;
e.g. '&' or '='
posn
the position of the token of interest, 0 based;
e.g. 1
Outputs
Returns text
Example usage
test=# select dblink_strtok(dblink_strtok('f=1&g=3&h=4','&',1),'=',1);
dblink_strtok
---------------
3
(1 row)
==================================================================
Name
dblink_get_pkey -- returns the field names of a relation's primary
key fields
Synopsis
dblink_get_pkey(name relname) RETURNS setof text
Inputs
relname
any relation name;
e.g. 'foobar'
Outputs
Returns setof text -- one row for each primary key field, in order of
precedence
Example usage
test=# select dblink_get_pkey('foobar');
dblink_get_pkey
-----------------
f1
f2
f3
f4
f5
(5 rows)
==================================================================
Name
dblink_last_oid -- Returns last inserted oid
Synopsis
dblink_last_oid(int res_id) RETURNS oid
Inputs
res_id
any resource id returned by dblink function;
Outputs
Returns oid of last inserted tuple
Example usage
test=# select dblink_last_oid(dblink('hostaddr=127.0.0.1 port=5432 dbname=mydb user=postgres password=mypasswd'
,'insert into mytable (f1, f2) values (1,2)'));
dblink_last_oid
----------------
16553
(1 row)
==================================================================
Name
dblink_build_sql_insert -- builds an insert statement using a local
tuple, replacing the selection key field
values with alternate supplied values
dblink_build_sql_delete -- builds a delete statement using supplied
values for selection key field values
dblink_build_sql_update -- builds an update statement using a local
tuple, replacing the selection key field
values with alternate supplied values
Synopsis
dblink_build_sql_insert(name relname
,int2vector primary_key_attnums
,int2 num_primary_key_atts
,_text src_pk_att_vals_array
,_text tgt_pk_att_vals_array) RETURNS text
dblink_build_sql_delete(name relname
,int2vector primary_key_attnums
,int2 num_primary_key_atts
,_text tgt_pk_att_vals_array) RETURNS text
dblink_build_sql_update(name relname
,int2vector primary_key_attnums
,int2 num_primary_key_atts
,_text src_pk_att_vals_array
,_text tgt_pk_att_vals_array) RETURNS text
Inputs
relname
any relation name;
e.g. 'foobar'
primary_key_attnums
vector of primary key attnums (1 based, see pg_index.indkey);
e.g. '1 2'
num_primary_key_atts
number of primary key attnums in the vector; e.g. 2
src_pk_att_vals_array
array of primary key values, used to look up the local matching
tuple, the values of which are then used to construct the SQL
statement
tgt_pk_att_vals_array
array of primary key values, used to replace the local tuple
values in the SQL statement
Outputs
Returns text -- requested SQL statement
Example usage
test=# select dblink_build_sql_insert('foo','1 2',2,'{"1", "a"}','{"1", "b''a"}');
dblink_build_sql_insert
--------------------------------------------------
INSERT INTO foo(f1,f2,f3) VALUES('1','b''a','1')
(1 row)
test=# select dblink_build_sql_delete('MyFoo','1 2',2,'{"1", "b"}');
dblink_build_sql_delete
---------------------------------------------
DELETE FROM "MyFoo" WHERE f1='1' AND f2='b'
(1 row)
test=# select dblink_build_sql_update('foo','1 2',2,'{"1", "a"}','{"1", "b"}');
dblink_build_sql_update
-------------------------------------------------------------
UPDATE foo SET f1='1',f2='b',f3='1' WHERE f1='1' AND f2='b'
(1 row)
==================================================================
Name
dblink_current_query -- returns the current query string
Synopsis
dblink_current_query () RETURNS text
Inputs
None
Outputs
Returns text -- a copy of the currently executing query
Example usage
test=# select dblink_current_query() from (select dblink('dbname=template1','select oid, proname from pg_proc where proname = ''byteacat''') as f1) as t1;
dblink_current_query
-----------------------------------------------------------------------------------------------------------------------------------------------------
select dblink_current_query() from (select dblink('dbname=template1','select oid, proname from pg_proc where proname = ''byteacat''') as f1) as t1;
(1 row)
==================================================================
Name
dblink_replace -- replace all occurences of substring-a in the
input-string with substring-b
Synopsis
dblink_replace(text input-string, text substring-a, text substring-b) RETURNS text
Inputs
input-string
the starting string, before replacement of substring-a
substring-a
the substring to find and replace
substring-b
the substring to be substituted in place of substring-a
Outputs
Returns text -- a copy of the starting string, but with all occurences of
substring-a replaced with substring-b
Example usage
test=# select dblink_replace('12345678901234567890','56','hello');
dblink_replace
----------------------------
1234hello78901234hello7890
(1 row)
==================================================================
-- Joe Conway -- Joe Conway

1325
contrib/dblink/dblink.c

File diff suppressed because it is too large Load Diff

79
contrib/dblink/dblink.h

@ -3,7 +3,8 @@
* *
* Functions returning results from a remote database * Functions returning results from a remote database
* *
* Copyright (c) Joseph Conway <joe.conway@mail.com>, 2001; * Copyright (c) Joseph Conway <mail@joeconway.com>, 2001, 2002,
* ALL RIGHTS RESERVED;
* *
* Permission to use, copy, modify, and distribute this software and its * Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose, without fee, and without a written agreement * documentation for any purpose, without fee, and without a written agreement
@ -33,10 +34,31 @@
#include "libpq-int.h" #include "libpq-int.h"
#include "fmgr.h" #include "fmgr.h"
#include "access/tupdesc.h" #include "access/tupdesc.h"
#include "access/heapam.h"
#include "catalog/catname.h"
#include "catalog/pg_index.h"
#include "catalog/pg_type.h"
#include "executor/executor.h" #include "executor/executor.h"
#include "executor/spi.h"
#include "lib/stringinfo.h"
#include "nodes/nodes.h" #include "nodes/nodes.h"
#include "nodes/execnodes.h" #include "nodes/execnodes.h"
#include "nodes/pg_list.h"
#include "parser/parse_type.h"
#include "tcop/tcopprot.h"
#include "utils/builtins.h" #include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/array.h"
#include "utils/syscache.h"
#ifdef NamespaceRelationName
#include "catalog/namespace.h"
#endif /* NamespaceRelationName */
/*
* Max SQL statement size
*/
#define DBLINK_MAX_SQLSTATE_SIZE 16384
/* /*
* This struct holds the results of the remote query. * This struct holds the results of the remote query.
@ -49,22 +71,75 @@ typedef struct
*/ */
int tup_num; int tup_num;
/*
* resource index number for this context
*/
int res_id_index;
/* /*
* the actual query results * the actual query results
*/ */
PGresult *res; PGresult *res;
} dblink_results; } dblink_results;
/*
* This struct holds results in the form of an array.
* Use fn_extra to hold a pointer to it across calls
*/
typedef struct
{
/*
* elem being accessed
*/
int elem_num;
/*
* number of elems
*/
int num_elems;
/*
* the actual array
*/
void *res;
} dblink_array_results;
/* /*
* External declarations * External declarations
*/ */
extern Datum dblink(PG_FUNCTION_ARGS); extern Datum dblink(PG_FUNCTION_ARGS);
extern Datum dblink_tok(PG_FUNCTION_ARGS); extern Datum dblink_tok(PG_FUNCTION_ARGS);
extern Datum dblink_strtok(PG_FUNCTION_ARGS);
extern Datum dblink_get_pkey(PG_FUNCTION_ARGS);
extern Datum dblink_last_oid(PG_FUNCTION_ARGS);
extern Datum dblink_build_sql_insert(PG_FUNCTION_ARGS);
extern Datum dblink_build_sql_delete(PG_FUNCTION_ARGS);
extern Datum dblink_build_sql_update(PG_FUNCTION_ARGS);
extern Datum dblink_current_query(PG_FUNCTION_ARGS);
extern Datum dblink_replace_text(PG_FUNCTION_ARGS);
/* /*
* Internal declarations * Internal declarations
*/ */
dblink_results *init_dblink_results(MemoryContext fn_mcxt); dblink_results *init_dblink_results(MemoryContext fn_mcxt);
dblink_array_results *init_dblink_array_results(MemoryContext fn_mcxt);
char **get_pkey_attnames(Oid relid, int16 *numatts);
char *get_strtok(char *fldtext, char *fldsep, int fldnum);
char *getvalue(HeapTuple tuple, TupleDesc tupdesc, int fnumber);
char *get_sql_insert(Oid relid, int16 *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals);
char *get_sql_delete(Oid relid, int16 *pkattnums, int16 pknumatts, char **tgt_pkattvals);
char *get_sql_update(Oid relid, int16 *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals);
static char *quote_literal_cstr(char *rawstr);
static char *quote_ident_cstr(char *rawstr);
int16 get_attnum_pk_pos(int16 *pkattnums, int16 pknumatts, int16 key);
HeapTuple get_tuple_of_interest(Oid relid, int16 *pkattnums, int16 pknumatts, char **src_pkattvals);
Oid get_relid_from_relname(char *relname);
dblink_results *get_res_ptr(int32 res_id_index);
void append_res_ptr(dblink_results *results);
void remove_res_ptr(dblink_results *results);
extern char *debug_query_string;
#endif /* DBLINK_H */ #endif /* DBLINK_H */

41
contrib/dblink/dblink.sql.in

@ -1,5 +1,38 @@
CREATE FUNCTION dblink (text,text) RETURNS setof int CREATE OR REPLACE FUNCTION dblink (text,text) RETURNS setof int
AS 'MODULE_PATHNAME','dblink' LANGUAGE 'c'; AS 'MODULE_PATHNAME','dblink' LANGUAGE 'c'
WITH (isstrict);
CREATE FUNCTION dblink_tok (int,int) RETURNS text CREATE OR REPLACE FUNCTION dblink_tok (int,int) RETURNS text
AS 'MODULE_PATHNAME','dblink_tok' LANGUAGE 'c'; AS 'MODULE_PATHNAME','dblink_tok' LANGUAGE 'c'
WITH (isstrict);
CREATE OR REPLACE FUNCTION dblink_strtok (text,text,int) RETURNS text
AS 'MODULE_PATHNAME','dblink_strtok' LANGUAGE 'c'
WITH (iscachable, isstrict);
CREATE OR REPLACE FUNCTION dblink_get_pkey (name) RETURNS setof text
AS 'MODULE_PATHNAME','dblink_get_pkey' LANGUAGE 'c'
WITH (isstrict);
CREATE OR REPLACE FUNCTION dblink_last_oid (int) RETURNS oid
AS 'MODULE_PATHNAME','dblink_last_oid' LANGUAGE 'c'
WITH (isstrict);
CREATE OR REPLACE FUNCTION dblink_build_sql_insert (name, int2vector, int2, _text, _text) RETURNS text
AS 'MODULE_PATHNAME','dblink_build_sql_insert' LANGUAGE 'c'
WITH (isstrict);
CREATE OR REPLACE FUNCTION dblink_build_sql_delete (name, int2vector, int2, _text) RETURNS text
AS 'MODULE_PATHNAME','dblink_build_sql_delete' LANGUAGE 'c'
WITH (isstrict);
CREATE OR REPLACE FUNCTION dblink_build_sql_update (name, int2vector, int2, _text, _text) RETURNS text
AS 'MODULE_PATHNAME','dblink_build_sql_update' LANGUAGE 'c'
WITH (isstrict);
CREATE OR REPLACE FUNCTION dblink_current_query () RETURNS text
AS 'MODULE_PATHNAME','dblink_current_query' LANGUAGE 'c';
CREATE OR REPLACE FUNCTION dblink_replace (text,text,text) RETURNS text
AS 'MODULE_PATHNAME','dblink_replace_text' LANGUAGE 'c'
WITH (iscachable, isstrict);