Postgres-XC 0.9.7 Documentation
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dblink_get_pkey

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

Note: The following description applies only to Postgres-XC

dblink module has not been tested with Postges-XC yet. Although there're no reason that dblink does not run in Postgres-XC, the development team leaves the test and the use of this module entirely to users.

This section is identical to the corresponding PostgreSQL reference manual.

Note: The following description applies only to PostgreSQL

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

Note: The following description applies only to PostgreSQL

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

Note: The following description applies only to PostgreSQL

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.

Example

Note: The following description applies only to PostgreSQL

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)
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