---
title: "dblink_get_pkey"
id: contrib-dblink-get-pkey
pg_version: "20devel"
---

<a id="contrib-dblink-get-pkey"></a>

# 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
```

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## 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. 

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## 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. <a id="id-1.11.7.21.22.7"></a>

## 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. 

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## 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)