pg_field_table

(PHP 5 >= 5.2.0, PHP 7, PHP 8)

pg_field_tableReturns the name or oid of the tables field

Descrizione

pg_field_table(PgSql\Result $result, int $field, bool $oid_only = false): string|int|false

pg_field_table() returns the name of the table that field belongs to, or the table's oid if oid_only is true.

Elenco dei parametri

result

An PgSql\Result instance, returned by pg_query(), pg_query_params() or pg_execute()(among others).

field

Field number, starting from 0.

oid_only

By default the tables name that field belongs to is returned but if oid_only is set to true, then the oid will instead be returned.

Valori restituiti

On success either the fields table name or oid, o false in caso di fallimento.

Log delle modifiche

Versione Descrizione
8.1.0 The result parameter expects an PgSql\Result instance now; previously, a resource was expected.

Esempi

Example #1 Getting table information about a field

<?php
$dbconn
= pg_connect("dbname=publisher") or die("Could not connect");

$res = pg_query($dbconn, "SELECT bar FROM foo");

echo
pg_field_table($res, 0);
echo
pg_field_table($res, 0, true);

$res = pg_query($dbconn, "SELECT version()");
var_dump(pg_field_table($res, 0));
?>

Il precedente esempio visualizzerĂ  qualcosa simile a:

foo
14379580

bool(false)

Note

Nota:

Returning the oid is much faster than returning the table name because fetching the table name requires a query to the database system table.

Vedere anche:

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User Contributed Notes 2 notes

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3
strata_ranger at hotmail dot com
15 years ago
pg_field_table is primarily useful for queries that involve joins between multiple tables, e.g:

<?php
$res
= pg_query("SELECT table1.foo, table2.bar FROM table1 JOIN table2");
echo
pg_field_table($res, 0); // Outputs 'table1'
echo pg_field_table($res, 1); // Outputs 'table2'
?>

However, be aware of a few easy 'gotchas':

1- If your query contains static values in its select-list, pg_field_table() will yield FALSE for those fields (because it was a static value, not one fetched from a table):

<?php
$res
= pg_query("SELECT 'foo', bar FROM table");
echo
pg_field_table($res, 0); // FALSE
echo pg_field_table($res, 1); // Outputs 'table'
?>

2- If you UNION two queries together from different tables, pg_field_table() will return FALSE for all fields:

<?php
$res
= pg_query("(Select foo, bar from table1) UNION (Select foo, bar from table2)");
echo
pg_field_table($res, 0); // FALSE
echo pg_field_table($res, 1); // FALSE
?>
up
1
giultar at gmail dot com
4 years ago
this function return an OID even if your field comes from a view or a select but return FALSE if your field comes from an UNION select
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