---
name: "dblink_get_pkey"
section: "3"
platform: "linux"
package: "postgresql"
version: "18.6-4"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/dblink_get_pkey"
---

# dblink\_get\_pkey(3)

returns the positions and field names of a relation's primary key fields

## 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)
```