dblink_get_pkey
dblink_get_pkey
dblink_get_pkey - returns the positions and field names of a relation's primary key fields
Synopsis
dblink_get_pkey(text relname) returns setof dblink_pkey_results
Description
dblink_get_pkey
provides information about the primary
key of a relation in the local database. This is sometimes useful
in generating queries to be sent to remote databases.
Arguments
-
relname -
Name of a local relation, for example
fooormyschema.mytab. Include double quotes if the name is mixed-case or contains special characters, for example"FooBar"; without quotes, the string will be folded to lower case.
Return Value
Returns one row for each primary key field, or no rows if the relation has no primary key. The result row type is defined as
CREATE TYPE dblink_pkey_results AS (position int, colname text);
The
position
column simply runs from 1 to
N
;
it is the number of the field within the primary key, not the number
within the table's columns.
Examples
CREATE TABLE foobar (
f1 int,
f2 int,
f3 int,
PRIMARY KEY (f1, f2, f3)
);
CREATE TABLE
SELECT * FROM dblink_get_pkey('foobar');
position | colname
----------+---------
1 | f1
2 | f2
3 | f3
(3 rows)