SunshinePHP Developer Conference 2015

pg_num_rows

(PHP 4 >= 4.2.0, PHP 5)

pg_num_rowsRestituiscein numero di tuple

Descrizione

int pg_num_rows ( resource $risultato )

pg_num_rows() restituisce il numero di tuple (righe) in un risultato PostgreSQL. risultato รจ una risorsa risultato ottenuta attraverso pg_query(). Restituisce -1 in caso di errore.

Nota:

Utilizzare pg_affected_rows() per ottenere il numero di righe modificate da query INSERT, UPDATE and DELETE.

Nota:

Questa funzione si chiamava pg_numrows().

Vedere anche pg_num_fields() e pg_affected_rows().

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User Contributed Notes 3 notes

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2
strata_ranger at hotmail dot com
5 years ago
As mentioned, if you are performing an INSERT/UPDATE or DELETE query and want to know the # of rows affected, you should use pg_affected_rows() instead of pg_num_rows().

However, you can also exploit postgres's RETURNING clause in your query to auto-select columns from the affected rows.  This has the advantage of being able to tell not only how many rows a query affects, but exactly which rows those were, especially if you return a primary-key column.

For example:

<?php

// Example query.  Let's say that this updates five rows in the source table.
$res = pg_query("Update foo set bar = 'new data' where foo.bar = 'old data' ");
pg_num_rows($res); // 0
pg_affected_rows($res); // 5
pg_fetch_all($res); // FALSE

// Same query, with a RETURNING clause.
$res = pg_query("Update foo set bar = 'new data' where foo.bar = 'old data' RETURNING foo.pkey");
pg_num_rows($res); // 5
pg_affected_rows($res); // 5
pg_fetch_all($res); // Multidimensional array corresponding to our affected rows & returned columns
?>
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1
ElDiablo
6 years ago
About preceding note, you shouldn't use pg_num_rows() for this.
You should have instead a look at pg_affected_rows().
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0
francisco at natserv dot com
6 years ago
Not sure why this documentation doesn't have the following note:
Note: Use pg_affected_rows() to get number of rows affected by INSERT, UPDATE and DELETE query.

Found on other resources. Adding here in case someone else is looking for the info.
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