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233 lines
5.8 KiB
Plaintext
233 lines
5.8 KiB
Plaintext
$PostgreSQL: pgsql/contrib/dblink/doc/misc,v 1.4 2006/09/02 21:11:15 joe Exp $
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==================================================================
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Name
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dblink_current_query -- returns the current query string
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Synopsis
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dblink_current_query () RETURNS text
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Inputs
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None
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Outputs
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Returns text -- a copy of the currently executing query
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Example usage
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test=# select dblink_current_query() from (select dblink('dbname=postgres','select oid, proname from pg_proc where proname = ''byteacat''') as f1) as t1;
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dblink_current_query
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-----------------------------------------------------------------------------------------------------------------------------------------------------
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select dblink_current_query() from (select dblink('dbname=postgres','select oid, proname from pg_proc where proname = ''byteacat''') as f1) as t1;
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(1 row)
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==================================================================
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Name
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dblink_get_pkey -- returns the position and field names of a relation's
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primary key fields
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Synopsis
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dblink_get_pkey(text relname) RETURNS setof dblink_pkey_results
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Inputs
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relname
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any relation name;
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e.g. 'foobar'
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Outputs
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Returns setof dblink_pkey_results -- one row for each primary key field,
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in order of position in the key. dblink_pkey_results is defined as follows:
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CREATE TYPE dblink_pkey_results AS (position int4, colname text);
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Example usage
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test=# select * from dblink_get_pkey('foobar');
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position | colname
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----------+---------
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1 | f1
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2 | f2
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3 | f3
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4 | f4
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5 | f5
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==================================================================
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Name
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dblink_build_sql_insert -- builds an insert statement using a local
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tuple, replacing the selection key field
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values with alternate supplied values
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dblink_build_sql_delete -- builds a delete statement using supplied
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values for selection key field values
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dblink_build_sql_update -- builds an update statement using a local
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tuple, replacing the selection key field
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values with alternate supplied values
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Synopsis
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dblink_build_sql_insert(text relname
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,int2vector primary_key_attnums
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,int2 num_primary_key_atts
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,_text src_pk_att_vals_array
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,_text tgt_pk_att_vals_array) RETURNS text
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dblink_build_sql_delete(text relname
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,int2vector primary_key_attnums
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,int2 num_primary_key_atts
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,_text tgt_pk_att_vals_array) RETURNS text
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dblink_build_sql_update(text relname
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,int2vector primary_key_attnums
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,int2 num_primary_key_atts
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,_text src_pk_att_vals_array
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,_text tgt_pk_att_vals_array) RETURNS text
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Inputs
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relname
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any relation name;
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e.g. 'foobar'
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primary_key_attnums
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vector of primary key attnums (1 based, see pg_index.indkey);
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e.g. '1 2'
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num_primary_key_atts
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number of primary key attnums in the vector; e.g. 2
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src_pk_att_vals_array
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array of primary key values, used to look up the local matching
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tuple, the values of which are then used to construct the SQL
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statement
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tgt_pk_att_vals_array
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array of primary key values, used to replace the local tuple
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values in the SQL statement
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Outputs
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Returns text -- requested SQL statement
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Example usage
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test=# select dblink_build_sql_insert('foo','1 2',2,'{"1", "a"}','{"1", "b''a"}');
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dblink_build_sql_insert
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--------------------------------------------------
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INSERT INTO foo(f1,f2,f3) VALUES('1','b''a','1')
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(1 row)
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test=# select dblink_build_sql_delete('MyFoo','1 2',2,'{"1", "b"}');
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dblink_build_sql_delete
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---------------------------------------------
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DELETE FROM "MyFoo" WHERE f1='1' AND f2='b'
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(1 row)
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test=# select dblink_build_sql_update('foo','1 2',2,'{"1", "a"}','{"1", "b"}');
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dblink_build_sql_update
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-------------------------------------------------------------
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UPDATE foo SET f1='1',f2='b',f3='1' WHERE f1='1' AND f2='b'
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(1 row)
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==================================================================
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Name
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dblink_get_connections -- returns a text array of all active named
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dblink connections
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Synopsis
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dblink_get_connections() RETURNS text[]
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Inputs
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none
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Outputs
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Returns text array of all active named dblink connections
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Example usage
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SELECT dblink_get_connections();
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==================================================================
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Name
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dblink_is_busy -- checks to see if named connection is busy
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with an async query
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Synopsis
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dblink_is_busy(text connname) RETURNS int
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Inputs
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connname
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The specific connection name to use.
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Outputs
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Returns 1 if connection is busy, 0 if it is not busy.
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If this function returns 0, it is guaranteed that dblink_get_result
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will not block.
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Example usage
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SELECT dblink_is_busy('dtest1');
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==================================================================
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Name
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dblink_cancel_query -- cancels any active query on the named connection
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Synopsis
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dblink_cancel_query(text connname) RETURNS text
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Inputs
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connname
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The specific connection name to use.
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Outputs
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Returns "OK" on success, or an error message on failure.
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Example usage
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SELECT dblink_cancel_query('dtest1');
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==================================================================
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Name
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dblink_error_message -- gets last error message on the named connection
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Synopsis
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dblink_error_message(text connname) RETURNS text
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Inputs
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connname
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The specific connection name to use.
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Outputs
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Returns last error message.
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Example usage
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SELECT dblink_error_message('dtest1');
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