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>dblink_get_pkey</H1
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><A
NAME="AEN147742"
></A
><H2
>Name</H2
>dblink_get_pkey&nbsp;--&nbsp;returns the positions and field names of a relation's
    primary key fields
   </DIV
><DIV
CLASS="REFSYNOPSISDIV"
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NAME="AEN147745"
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><H2
>Synopsis</H2
><PRE
CLASS="SYNOPSIS"
>dblink_get_pkey(text relname) returns setof dblink_pkey_results</PRE
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><A
NAME="AEN147747"
></A
><H2
>Description</H2
><P
>    <CODE
CLASS="FUNCTION"
>dblink_get_pkey</CODE
> 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.
   </P
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></A
><H2
>Arguments</H2
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="PARAMETER"
>relname</TT
></DT
><DD
><P
>       Name of a local relation, for example <TT
CLASS="LITERAL"
>foo</TT
> or
       <TT
CLASS="LITERAL"
>myschema.mytab</TT
>.  Include double quotes if the
       name is mixed-case or contains special characters, for
       example <TT
CLASS="LITERAL"
>"FooBar"</TT
>; without quotes, the string
       will be folded to lower case.
      </P
></DD
></DL
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><A
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></A
><H2
>Return Value</H2
><P
>    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

</P><PRE
CLASS="PROGRAMLISTING"
>CREATE TYPE dblink_pkey_results AS (position int, colname text);</PRE
><P>

    The <TT
CLASS="LITERAL"
>position</TT
> column simply runs from 1 to <TT
CLASS="REPLACEABLE"
><I
>N</I
></TT
>;
    it is the number of the field within the primary key, not the number
    within the table's columns.
   </P
></DIV
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><A
NAME="AEN147768"
></A
><H2
>Examples</H2
><PRE
CLASS="SCREEN"
>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)</PRE
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