postgres/contrib/dblink/doc/misc

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==================================================================
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_get_pkey -- returns the position and field names of a relation's
primary key fields
Synopsis
dblink_get_pkey(text relname) RETURNS setof dblink_pkey_results
Inputs
relname
any relation name;
e.g. 'foobar'
Outputs
Returns setof dblink_pkey_results -- one row for each primary key field,
in order of position in the key. dblink_pkey_results is defined as follows:
CREATE TYPE dblink_pkey_results AS (position int4, colname text);
Example usage
test=# select * from dblink_get_pkey('foobar');
position | colname
----------+---------
1 | f1
2 | f2
3 | f3
4 | f4
5 | f5
==================================================================
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(text 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(text relname
,int2vector primary_key_attnums
,int2 num_primary_key_atts
,_text tgt_pk_att_vals_array) RETURNS text
dblink_build_sql_update(text 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)