NAME

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 foo or myschema.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)