PostgreSQL Funções

Notas

Nota:

Nem todas as funções são suportadas por todas as compilações. Isso vai depender da versão da libpq (A interface cliente em C para PostgreSQL) e como esta foi compilada. Se há alguma função ausente, é porque a libpq não suporta a característica exigida por esta função.

Nota:

Muitas funções do PostgreSQL aceitam connection como o primeiro parâmetro opcional. Se ele não é fornecido, a última conexão aberta é usada. Se não existir, a função retorna false.

Nota:

PostgreSQL automaticamente converte todos identificadores (e.g. nomes de tabela/coluna) para minúsculo na criação do objeto e na query. Para força o uso misto de maiúsculo ou minúsculo, você precisa usar escape no identificador usando aspas dupla ("").

Nota:

PostgreSQL não tem comandos especiais para obter informação dos dados do banco de dados (dicionário de dados) (eg. todas as tabelas do banco de dados atual). Ao invés, há um schema padrão chamado information_schema no PostgreSQL 7.4 e superior contendo views do sistema com todas as informações necessárias, em um form fácil de acessá-las. Veja a » Documentação do PostgreSQL para maiores detalhes.

Índice

  • pg_affected_rows — Retorna o número de registros afetados (linhas)
  • pg_cancel_query — Cancela uma consulta (query) assíncrona
  • pg_client_encoding — Retorna a codificação do cliente
  • pg_close — Fecha uma conexão PostgreSQL
  • pg_connect_poll — Poll the status of an in-progress asynchronous PostgreSQL connection attempt
  • pg_connect — Abre uma conexão PostgreSQL
  • pg_connection_busy — Verifica se a conexão está ocupada ou não
  • pg_connection_reset — Reinicia uma conexão (reconecta)
  • pg_connection_status — Retorna o status da conexão
  • pg_consume_input — Reads input on the connection
  • pg_convert — Converte os valores de um array associativo em uma declaração SQL apropriada.
  • pg_copy_from — Insere registros em uma tabela a partir de um array
  • pg_copy_to — Copia uma tabela em um array
  • pg_dbname — Retorna o nome do banco de dados
  • pg_delete — Remove registros.
  • pg_end_copy — Sincroniza com o backend PostgreSQL
  • pg_escape_bytea — Gera binários para o tipo bytea
  • pg_escape_identifier — Escape a identifier for insertion into a text field
  • pg_escape_literal — Escape a literal for insertion into a text field
  • pg_escape_string — Gera string para o tipo text/char
  • pg_execute — Sends a request to execute a prepared statement with given parameters, and waits for the result
  • pg_fetch_all_columns — Fetches all rows in a particular result column as an array
  • pg_fetch_all — Retorna todas as linhas (registros) como um array
  • pg_fetch_array — Retorna uma linha (registro) como um array
  • pg_fetch_assoc — Retorna uma linha (registro) como uma matriz associativa
  • pg_fetch_object — Retorna uma linha (registro) como um objeto
  • pg_fetch_result — Retorna valores a partir de um recurso (resource) de resultado
  • pg_fetch_row — Retorna uma linha como um array enumerado
  • pg_field_is_null — Testa se o campo é null
  • pg_field_name — Retorna o nome de um campo
  • pg_field_num — Retorna o número do campo referido
  • pg_field_prtlen — Retorna o comprimento impresso
  • pg_field_size — Retorna o tamanho de armazenamento interno de um campo
  • pg_field_table — Returns the name or oid of the tables field
  • pg_field_type_oid — Returns the type ID (OID) for the corresponding field number
  • pg_field_type — Retorna o nome do tipo para o campo de nome correspondente
  • pg_flush — Flush outbound query data on the connection
  • pg_free_result — Libera a memória usada pelo resultado
  • pg_get_notify — Gets SQL NOTIFY message
  • pg_get_pid — Gets the backend's process ID
  • pg_get_result — Retorna o resultado de uma consulta (query) assíncrona
  • pg_host — Retorna o nome da máquina associada a uma conexão
  • pg_insert — Insere um array na tabela
  • pg_last_error — Retorna a string da última mensagem de erro de uma conexão
  • pg_last_notice — Retorna a última notificação do servidor PostgreSQL
  • pg_last_oid — Retorna o último oid do objeto
  • pg_lo_close — Fecha um objeto grande (large object)
  • pg_lo_create — Cria um objeto grande (large object)
  • pg_lo_export — Exporta um objeto grande (large object) para um arquivo
  • pg_lo_import — Importa um objeto grande (large object) a partir de um arquivo
  • pg_lo_open — Abre um objeto grande (large object)
  • pg_lo_read_all — Lê um objeto grande (large object) inteiro e o envia diretamente para o navegador
  • pg_lo_read — Lê um objeto grande (large object)
  • pg_lo_seek — Procura uma posição em um objeto grande (large object)
  • pg_lo_tell — Retorna a posição atual de um objeto grande (large object)
  • pg_lo_truncate — Truncates a large object
  • pg_lo_unlink — Remove um objeto grande (large object)
  • pg_lo_write — Escreve em um objeto grande (large object)
  • pg_meta_data — Retorna os metadados da tabela.
  • pg_num_fields — Retorna o número de campos
  • pg_num_rows — Retorna o número de linhas
  • pg_options — Retorna as opções associadas com a conexão
  • pg_parameter_status — Looks up a current parameter setting of the server
  • pg_pconnect — Abre uma conexão PostgreSQL persistente
  • pg_ping — Faz um ping na conexão com o banco de dados
  • pg_port — Retorna o número da porta associada com a conexão.
  • pg_prepare — Submits a request to create a prepared statement with the given parameters, and waits for completion
  • pg_put_line — Envia uma string terminada em NULL para o backend PostgreSQL
  • pg_query_params — Submits a command to the server and waits for the result, with the ability to pass parameters separately from the SQL command text
  • pg_query — Executa uma consulta (query)
  • pg_result_error_field — Returns an individual field of an error report
  • pg_result_error — Retorna a mensagem de erro associada a um resultado
  • pg_result_seek — Altera a posição do ponteiro interno de um recurso (resource) de resultado
  • pg_result_status — Retorna o status do resultado da consulta (query)
  • pg_select — Seleciona registros.
  • pg_send_execute — Sends a request to execute a prepared statement with given parameters, without waiting for the result(s)
  • pg_send_prepare — Sends a request to create a prepared statement with the given parameters, without waiting for completion
  • pg_send_query_params — Submits a command and separate parameters to the server without waiting for the result(s)
  • pg_send_query — Envia uma consulta (query) assincrona
  • pg_set_client_encoding — Define a codificação do cliente
  • pg_set_error_verbosity — Determines the verbosity of messages returned by pg_last_error and pg_result_error
  • pg_socket — Get a read only handle to the socket underlying a PostgreSQL connection
  • pg_trace — Habilita rastreamento em uma conexão PostgreSQL
  • pg_transaction_status — Returns the current in-transaction status of the server
  • pg_tty — Retorna o nome da tty associada com a conexão
  • pg_unescape_bytea — Faz escape binário para o tipo bytea
  • pg_untrace — Desabilita o rastreamento de uma conexão PostgreSQL
  • pg_update — Atualiza uma tabela.
  • pg_version — Returns an array with client, protocol and server version (when available)
add a note add a note

User Contributed Notes 18 notes

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4
saberit at home dot com
22 years ago
I tried compiling PHP from source with PostgreSQL support (./configure --with-pgsql=/usr/local/pgsql) and ran into a bunch of problems when trying to 'make'. The problem was that some of the PostgreSQL headers were not installed by default when I installed PostgreSQL from source. When installing PostgreSQL make sure you 'make install-all-headers' after you 'make install'.
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10
Tony Murray
11 years ago
A simple conversion for 1D PostgreSQL array data:

// =====
//Example #1 (An array of IP addresses):
<?php
  $pgsqlArr
= '{192.168.1.1,10.1.1.1}';

 
preg_match('/^{(.*)}$/', $pgsqlArr, $matches);
 
$phpArr = str_getcsv($matches[1]);

 
print_r($phpArr);
}
// Output:
// Array
// (
//    [0] => 192.168.1.1
//    [1] => 10.1.1.1
// )
// =====

// =====
// Example #2 (An array of strings including spaces and commas):
<?php
  $pgsqlArr
= '{string1,string2,"string,3","string 4"}';

 
preg_match('/^{(.*)}$/', $pgsqlArr, $matches);
 
$phpArr = str_getcsv($matches[1]);

 
print_r($phpArr);
}
// Output:
// Array
// (
//    [0] => string1
//    [1] => string2
//    [2] => string,3
//    [3] => string 4
// )
// =====
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3
74012 dot 2773 at compuserve dot com
19 years ago
for just a list of tables, this works with postgresql-7.2.1:

function pg_list_tables($db) {
    $sql = "select relname from pg_stat_user_tables order by relname;";
    return pg_query($db, $sql);
}
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2
1413 at blargh dot com
18 years ago
Here is some quick and dirty code to convert Postgres-returned arrays into PHP arrays.  There's probably a billion bugs, but since I'm only dealing with variable-depth-and-length arrays of integers, it works for my needs.

Most notably, any data that might have commas in it won't work right...

<?php
function PGArrayToPHPArray($pgArray)
{
 
$ret = array();
 
$stack = array(&$ret);
 
$pgArray = substr($pgArray, 1, -1);
 
$pgElements = explode(",", $pgArray);
 
 
ArrayDump($pgElements);

  foreach(
$pgElements as $elem)
    {
      if(
substr($elem,-1) == "}")
        {
         
$elem = substr($elem,0,-1);
         
$newSub = array();
          while(
substr($elem,0,1) != "{")
            {
             
$newSub[] = $elem;
             
$elem = array_pop($ret);
            }
         
$newSub[] = substr($elem,1);
         
$ret[] = array_reverse($newSub);
        }
      else
       
$ret[] = $elem;
    }
  return
$ret;
}
?>
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2
abondi at ijk dot it
19 years ago
I've found another function to mimic the following mysql list tables function (http://www.php.net/manual/en/function.mysql-list-tables.php) that's more useful for my target:

function pg_list_tables() {
      $sql = "SELECT a.relname AS Name
          FROM pg_class a, pg_user b
          WHERE ( relkind = 'r') and relname !~ '^pg_' AND relname !~ '^sql_'
          AND relname !~ '^xin[vx][0-9]+' AND b.usesysid = a.relowner
          AND NOT (EXISTS (SELECT viewname FROM pg_views WHERE viewname=a.relname));";
      return(pg_query($conn, $sql));
}
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2
daniel at bichara dot com dot br
21 years ago
Running RedHat Linux and Apache with suexec enabled you must include pgsql.so on each .php file using dl("pgsql.so") and remove "extension=pgsql.so" from php.ini, otherwise Apache (httpd) will not start.
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1
WillowCatkin at hotmail dot com
18 years ago
There is an example:
<?php
/*
* Define PostgreSQL database server connect parameters.
*/
define('PGHOST','10.0.0.218');
define('PGPORT',5432);
define('PGDATABASE','example');
define('PGUSER', 'root');
define('PGPASSWORD', 'nopass');
define('PGCLIENTENCODING','UNICODE');
define('ERROR_ON_CONNECT_FAILED','Sorry, can not connect the database server now!');

/*
* Merge connect string and connect db server with default parameters.
*/
pg_pconnect('host=' . PGHOST . ' port=' . PGPORT . ' dbname=' . PGDATABASE . ' user=' . PGUSER . ' password=' . PGPASSWORD);

/*
* generate sql statements to call db-server-side stored procedure(or function)
* @parameter    string    $proc        stored procedure name.
* @parameter    array    $paras        parameters, 2 dimensions array.
* @return        string    $sql = 'select "proc"(para1,para2,para3);'
* @example    pg_prepare('userExists',
*                            array(
*                                array('userName','chin','string'),
*                                array('userId','7777','numeric')
*                            )
* )
*/
function pg_prepare($proc, $paras)
{
   
$sql = 'select "' . $proc . '"(';
   
$sql .= $paras[0][2] == 'numeric' ? $paras[0][1] : "'" . str_replace("'","''",$paras[0][1]) . "'";
   
$len = count($paras);
    for (
$i = 1; $i < $len; $i ++)
    {
       
$sql .= ',';
       
$sql .= $paras[$i][2] == 'numeric' ? $paras[$i][1] : "'" . str_replace("'","''",$paras[$i][1]) . "'";
    }
   
$sql .= ');';
    return
$sql;
}
?>
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0
Anonymous
17 years ago
Lots of advice on stored procedures didn't work for me.  This did:

<?php
$response
= pg_query( $connection, "BEGIN; DECLARE s CURSOR FOR SELECT get_consumer('harry'); FETCH ALL IN s; END;" );
?>

..where harry looks like this:

CREATE OR REPLACE FUNCTION get_consumer( varchar )
RETURNS refcursor
AS '
DECLARE
  _name          ALIAS FOR $1;
  r              refcursor;
BEGIN
  OPEN r FOR SELECT name FROM consumer
  WHERE
    consumer.name = _name
  ;
  RETURN r;
END
' LANGUAGE 'plpgsql';
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0
anis_wn at gawab dot com
18 years ago
Setting up PostgreSQL for higher security PHP connection.

Case:
We want to connect to PostgreSQL database using username and password supplied by webuser at login time.

Fact (Linux):
Apache (perhaps other servers, too) running the server as (default to) apache user account. So if you connect to PostgreSQL using default user, apache will be assingned for it. If you hard code the user and password in your PHP script, you'll loose security restriction from PostgreSQL.

Solution:
(You are assumed to have enough privilege to do these things, though)
1. Edit pg_hba.conf to have the line like the one below
    host    db_Name    [web_server_ip_address] [ip_address_mask] md5
2. Add to you script the login page that submits username and password.
3. Use those information to login to PostgreSQL like these...
<?
    $conn
= "host=$DBHost port=$DBPort dbname=$DBName ".
           
"user='{$_POST['dbUsername']}' password='{$_POST['dbPassword']}'";
   
$db = pg_connect ($conn);
[
your other codes go here...]
?>
4. You must add users in PostgreSQL properly.
5. For your convenience, you can store the username and password to $_SESSION variable.

Good luck.
Anis WN
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0
anonymous at unknown dot com
21 years ago
I just wanted to add to my previous post I've got the system up and running.
Environment: Windows XP, Apache 1.3.23, Php 4.3 RC2, PostGreSQL beta4 native windows build

Installation was fairly easy:
1. read the readme.txt
2. edit the setenv.bat as described in readme
3. run 'initdb'
    all execs are in /bin
    help is accessed like <command> --help
4. Start the psql deamon - you may want to create a batch file like
    'D:\postgres_beta4\bin\postmaster -h localhost -D D:/postgres_beta4/data'

    --deamon should be up and running now--

You can login into a shell from a console like
    'psql -h localhost -d <username>'

You must load the postgresql extension by editing the php.ini and restarting apache in order to access psql with php.

And one final not: when running
    $dbconn = pg_connect ("host=localhost port=5432 dbname=$dbname user=$user");
remember that $user and or $dbname is CASESENSITIVE.

Oh yeah, I created the data dir manually - don't know whether that was necessary

Grtz Vargo
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0
passion at monkey dot org
22 years ago
I've tried to mimic the following mysql database connection functions for postgres.
http://www.php.net/manual/en/function.mysql-list-dbs.php
http://www.php.net/manual/en/function.mysql-list-tables.php

These are assuming that you're passing in $link as the result from pg_connect:

function pg_list_dbs($link)

    $sql = 'SELECT datname FROM pg_database';
    return (pg_query($link, $sql));


function pg_list_tables($link)

    $sql = "SELECT relname FROM pg_class WHERE relname !~ '^pg_'";
    return (pg_query($link, $sql));
}
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0
!spamcraig at ahdore dot com
23 years ago
If you want to extract data from select statements, you need to store the result index, and then apply pg_result to that value. Basically, do this

$resultIdx = pg_query ($database, "select * from tablename");
$mySelect = pg_fetch_result($resultIdx, 0, 0);  // gets column 0 of tuple 0
echo("My select: [".$mySelect."]");

I'm new to php and had to do some fiddling around to work this out. It's reasonably elementary, but not demonstrated by the examples on these pages. Hopefully it will come in useful to someone else.
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-1
mystran at wasteland dot pp dot htv dot fi
22 years ago
Nice to know fact that I didn't find documented here.

PHP will return values of PostgreSQL boolean datatype as single character strings "t" and "f", not PHP true and false.

[Editor's Note]
't' or 'f' is valid boolean expression for PostgreSQL.

All values from PostgreSQL are strings, since PostgreSQL integer, float may be much larger than PHP's native int, double can handle. PostgreSQL array is not supported.
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-1
Chris KL
18 years ago
Here is a better array parser for PHP.  It will work with 1-d arrays only.  Unlike the example below it will work in all cases.

    /**
     * Change a db array into a PHP array
     * @param $arr String representing the DB array
     * @return A PHP array
     */
    function phpArray($dbarr) {
        // Take off the first and last characters (the braces)
        $arr = substr($dbarr, 1, strlen($dbarr) - 2);

        // Pick out array entries by carefully parsing.  This is necessary in order
        // to cope with double quotes and commas, etc.
        $elements = array();
        $i = $j = 0;       
        $in_quotes = false;
        while ($i < strlen($arr)) {
            // If current char is a double quote and it's not escaped, then
            // enter quoted bit
            $char = substr($arr, $i, 1);
            if ($char == '"' && ($i == 0 || substr($arr, $i - 1, 1) != '\\'))
                $in_quotes = !$in_quotes;
            elseif ($char == ',' && !$in_quotes) {
                // Add text so far to the array
                $elements[] = substr($arr, $j, $i - $j);
                $j = $i + 1;
            }
            $i++;
        }
        // Add final text to the array
        $elements[] = substr($arr, $j);

        // Do one further loop over the elements array to remote double quoting
        // and escaping of double quotes and backslashes
        for ($i = 0; $i < sizeof($elements); $i++) {
            $v = $elements[$i];
            if (strpos($v, '"') === 0) {
                $v = substr($v, 1, strlen($v) - 2);
                $v = str_replace('\\"', '"', $v);
                $v = str_replace('\\\\', '\\', $v);
                $elements[$i] = $v;
            }
        }

        return $elements;
    }
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-1
adaml at mimuw edu pl
19 years ago
Yes, PHP does support stored procedures
You have to add "select" before the name of the
procedure, just like that:

$result = pg_querry($conn, "SELECT procedure_x($aa)");

if a procedure returns a cursor you do something like that:

$result = pg_query($conn, "SELECT procedure_x('rcursor'); FETCH ALL IN rcursor");
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-1
hubert at hubertmuller dot com
22 years ago
The best way to find the separated list of tables, sequences, keys etc is:

SELECT relname FROM pg_class WHERE relkind='<value>' AND relname !~ '^pg_';

<value> takes:
i for keys,
r for relations,
S for sequences

Note that all tables names that begins with 'pg_' are PostgreSQL internal tables (this explain why I use AND relname !~ '^pg_' condition).
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-1
bleach at chek dot com
24 years ago
If you want to see all the objects in a database, you can find that information in the pg_class table. <BR>
SELECT * FROM pg_class;<BR>
Now this is going to be kind of long and complex, to see how psql command handles the \d and other things. use the syntax.  psql -E <Database>, ie psql -E mydatabase <BR>
What this will do is show the SQL command used for everything. So when you type a \d or something, it shows the SQL query used for the result.
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-8
Anonymous
17 years ago
Chris KL: Will parse well {"\\"}? The second " will be treat as escaped while it shoudn't...
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