PostgreSQL Functions

Notes

Note:
Not all functions are supported by all builds. It depends on your libpq (The PostgreSQL C client library) version and how libpq is compiled. If PHP PostgreSQL extensions are missing, then it is because your libpq version does not support them.

Note:
Most PostgreSQL functions accept connection as the optional first parameter. If it is not provided, the last opened connection is used. If it doesn't exist, functions return false.

Note:
PostgreSQL automatically folds all identifiers (e.g. table/column names) to lower-case values at object creation time and at query time. To force the use of mixed or upper case identifiers, you must escape the identifier using double quotes ("").

Note:
PostgreSQL does not have special commands for fetching database schema information (eg. all the tables in the current database). Instead, there is a standard schema named information_schema in PostgreSQL 7.4 and above containing system views with all the necessary information, in an easily queryable form. See the » PostgreSQL Documentation for full details.

pg_affected_rows — Returns number of affected records (tuples)
pg_cancel_query — Cancel an asynchronous query
pg_client_encoding — Gets the client encoding
pg_close — Closes a PostgreSQL connection
pg_connect — Open a PostgreSQL connection
pg_connect_poll — Poll the status of an in-progress asynchronous PostgreSQL connection attempt
pg_connection_busy — Get connection is busy or not
pg_connection_reset — Reset connection (reconnect)
pg_connection_status — Get connection status
pg_consume_input — Reads input on the connection
pg_convert — Convert associative array values into forms suitable for SQL statements
pg_copy_from — Insert records into a table from an array
pg_copy_to — Copy a table to an array
pg_dbname — Get the database name
pg_delete — Deletes records
pg_end_copy — Sync with PostgreSQL backend
pg_escape_bytea — Escape a string for insertion into a bytea field
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 — Escape a string for query
pg_execute — Sends a request to execute a prepared statement with given parameters, and waits for the result
pg_fetch_all — Fetches all rows from a result as an array
pg_fetch_all_columns — Fetches all rows in a particular result column as an array
pg_fetch_array — Fetch a row as an array
pg_fetch_assoc — Fetch a row as an associative array
pg_fetch_object — Fetch a row as an object
pg_fetch_result — Returns values from a result instance
pg_fetch_row — Get a row as an enumerated array
pg_field_is_null — Test if a field is SQL NULL
pg_field_name — Returns the name of a field
pg_field_num — Returns the field number of the named field
pg_field_prtlen — Returns the printed length
pg_field_size — Returns the internal storage size of the named field
pg_field_table — Returns the name or oid of the tables field
pg_field_type — Returns the type name for the corresponding field number
pg_field_type_oid — Returns the type ID (OID) for the corresponding field number
pg_flush — Flush outbound query data on the connection
pg_free_result — Free result memory
pg_get_notify — Gets SQL NOTIFY message
pg_get_pid — Gets the backend's process ID
pg_get_result — Get asynchronous query result
pg_host — Returns the host name associated with the connection
pg_insert — Insert array into table
pg_last_error — Get the last error message string of a connection
pg_last_notice — Returns the last notice message from PostgreSQL server
pg_last_oid — Returns the last row's OID
pg_lo_close — Close a large object
pg_lo_create — Create a large object
pg_lo_export — Export a large object to file
pg_lo_import — Import a large object from file
pg_lo_open — Open a large object
pg_lo_read — Read a large object
pg_lo_read_all — Reads an entire large object and send straight to browser
pg_lo_seek — Seeks position within a large object
pg_lo_tell — Returns current seek position a of large object
pg_lo_truncate — Truncates a large object
pg_lo_unlink — Delete a large object
pg_lo_write — Write to a large object
pg_meta_data — Get meta data for table
pg_num_fields — Returns the number of fields in a result
pg_num_rows — Returns the number of rows in a result
pg_options — Get the options associated with the connection
pg_parameter_status — Looks up a current parameter setting of the server
pg_pconnect — Open a persistent PostgreSQL connection
pg_ping — Ping database connection
pg_port — Return the port number associated with the connection
pg_prepare — Submits a request to create a prepared statement with the given parameters, and waits for completion
pg_put_line — Send a NULL-terminated string to PostgreSQL backend
pg_query — Execute a query
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_result_error — Get error message associated with result
pg_result_error_field — Returns an individual field of an error report
pg_result_seek — Set internal row offset in result instance
pg_result_status — Get status of query result
pg_select — Select records
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 — Sends asynchronous query
pg_send_query_params — Submits a command and separate parameters to the server without waiting for the result(s)
pg_set_client_encoding — Set the client encoding
pg_set_error_context_visibility — Determines the visibility of the context's error messages returned by pg_last_error and pg_result_error
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 — Enable tracing a PostgreSQL connection
pg_transaction_status — Returns the current in-transaction status of the server
pg_tty — Return the TTY name associated with the connection
pg_unescape_bytea — Unescape binary for bytea type
pg_untrace — Disable tracing of a PostgreSQL connection
pg_update — Update table
pg_version — Returns an array with client, protocol and server version (when available)

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User Contributed Notes 17 notes

down

Tony Murray ¶

12 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
// )
// =====

down

abondi at ijk dot it ¶

20 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));
}

down

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;
}
?>

down

74012 dot 2773 at compuserve dot com ¶

20 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);
}

down

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.

down

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'.

down

-1

WillowCatkin at hotmail dot com ¶

19 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;
}
?>

down

-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.

down

-1

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';

down

-2

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

down

-2

anis_wn at gawab dot com ¶

19 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

down

-2

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");

down

-2

hubert at hubertmuller dot com ¶

23 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).

down

-2

!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.

down

-2

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.

down

-3

passion at monkey dot org ¶

23 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));

}

down

-3

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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PostgreSQL Functions

Notes

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User Contributed Notes 17 notes