PHP: PostgreSQL Functions - Manual

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# CXXIV. PostgreSQL Functions

# Введение

PostgreSQL database is Open Source product and available without cost. Postgres, developed originally in the UC Berkeley Computer Science Department, pioneered many of the object-relational concepts now becoming available in some commercial databases. It provides SQL92/SQL99 language support, transactions, referential integrity, stored procedures and type extensibility. PostgreSQL is an open source descendant of this original Berkeley code.

# Требования

To use PostgreSQL support, you need PostgreSQL 6.5 or later, PostgreSQL 8.0 or later to enable all PostgreSQL module features. PostgreSQL supports many character encodings including multibyte character encoding. The current version and more information about PostgreSQL is available at http://www.postgresql.org/ and the PostgreSQL Documentation.

# Установка

In order to enable PostgreSQL support, `--with-pgsql[=DIR]` is required when you compile PHP. DIR is the PostgreSQL base install directory, defaults to `/usr/local/pgsql`. If shared object module is available, PostgreSQL module may be loaded using extension directive in `php.ini` or dl() function.

# Настройка во время выполнения

Поведение этих функций зависит от установок в `php.ini`.

Таблица 1. PostgreSQL configuration options

Name | Default | Changeable | Changelog
--- | --- | --- | ---
pgsql.allow_persistent | "1" | PHP_INI_SYSTEM |
pgsql.max_persistent | "-1" | PHP_INI_SYSTEM |
pgsql.max_links | "-1" | PHP_INI_SYSTEM |
pgsql.auto_reset_persistent | "0" | PHP_INI_SYSTEM | Available since PHP 4.2.0.
pgsql.ignore_notice | "0" | PHP_INI_ALL | Available since PHP 4.3.0.
pgsql.log_notice | "0" | PHP_INI_ALL | Available since PHP 4.3.0.

Для подробного описания констант PHP_INI_*, обратитесь к документации функции ini_set().

Краткое разъяснение конфигурационных директив.

`pgsql.allow_persistent` boolean

  Whether to allow persistent Postgres connections.

`pgsql.max_persistent` integer

  The maximum number of persistent Postgres connections per process.

`pgsql.max_links` integer

  The maximum number of Postgres connections per process, including persistent connections.

`pgsql.auto_reset_persistent` integer

  Detect broken persistent links with pg_pconnect(). Needs a little overhead.

`pgsql.ignore_notice` integer

  Whether or not to ignore PostgreSQL backend notices.

`pgsql.log_notice` integer

  Whether or not to log PostgreSQL backends notice messages. The PHP directive pgsql.ignore_notice must be off in order to log notice messages.

# Типы ресурсов

There are two resource types used in the PostgreSQL module. The first one is the link identifier for a database connection, the second a resource which holds the result of a query.

# Предопределенные константы

Перечисленные ниже константы определены данным расширением и могут быть доступны только в том случае, если PHP был собран с поддержкой этого расширения или же в том случае, если данное расширение подгружается во время выполнения.

`PGSQL_ASSOC` (integer)

  Passed to pg_fetch_array(). Return an associative array of field names and values.

`PGSQL_NUM` (integer)

  Passed to pg_fetch_array(). Return a numerically indexed array of field numbers and values.

`PGSQL_BOTH` (integer)

  Passed to pg_fetch_array(). Return an array of field values that is both numerically indexed (by field number) and associated (by field name).

`PGSQL_CONNECT_FORCE_NEW` (integer)

  Passed to pg_connect() to force the creation of a new connection, rather then re-using an existing identical connection.

`PGSQL_CONNECTION_BAD` (integer)

  Returned by pg_connection_status() indicating that the database connection is in an invalid state.

`PGSQL_CONNECTION_OK` (integer)

  Returned by pg_connection_status() indicating that the database connection is in a valid state.

`PGSQL_SEEK_SET` (integer)

  Passed to pg_lo_seek(). Seek operation is to begin from the start of the object.

`PGSQL_SEEK_CUR` (integer)

  Passed to pg_lo_seek(). Seek operation is to begin from the current position.

`PGSQL_SEEK_END` (integer)

  Passed to pg_lo_seek(). Seek operation is to begin from the end of the object.

`PGSQL_EMPTY_QUERY` (integer)

  Returned by pg_result_status(). The string sent to the server was empty.

`PGSQL_COMMAND_OK` (integer)

  Returned by pg_result_status(). Successful completion of a command returning no data.

`PGSQL_TUPLES_OK` (integer)

  Returned by pg_result_status(). Successful completion of a command returning data (such as a `SELECT` or `SHOW`).

`PGSQL_COPY_OUT` (integer)

  Returned by pg_result_status(). Copy Out (from server) data transfer started.

`PGSQL_COPY_IN` (integer)

  Returned by pg_result_status(). Copy In (to server) data transfer started.

`PGSQL_BAD_RESPONSE` (integer)

  Returned by pg_result_status(). The server's response was not understood.

`PGSQL_NONFATAL_ERROR` (integer)

  Returned by pg_result_status(). A nonfatal error (a notice or warning) occurred.

`PGSQL_FATAL_ERROR` (integer)

  Returned by pg_result_status(). A fatal error occurred.

`PGSQL_TRANSACTION_IDLE` (integer)

  Returned by pg_transaction_status(). Connection is currently idle, not in a transaction.

`PGSQL_TRANSACTION_ACTIVE` (integer)

  Returned by pg_transaction_status(). A command is in progress on the connection. A query has been sent via the connection and not yet completed.

`PGSQL_TRANSACTION_INTRANS` (integer)

  Returned by pg_transaction_status(). The connection is idle, in a transaction block.

`PGSQL_TRANSACTION_INERROR` (integer)

  Returned by pg_transaction_status(). The connection is idle, in a failed transaction block.

`PGSQL_TRANSACTION_UNKNOWN` (integer)

  Returned by pg_transaction_status(). The connection is bad.

`PGSQL_DIAG_SEVERITY` (integer)

  Passed to pg_result_error_field(). The severity; the field contents are `ERROR`, `FATAL`, or `PANIC` (in an error message), or `WARNING`, `NOTICE`, `DEBUG`, `INFO`, or `LOG` (in a notice message), or a localized translation of one of these. Always present.

`PGSQL_DIAG_SQLSTATE` (integer)

  Passed to pg_result_error_field(). The SQLSTATE code for the error. The SQLSTATE code identifies the type of error that has occurred; it can be used by front-end applications to perform specific operations (such as error handling) in response to a particular database error. This field is not localizable, and is always present.

`PGSQL_DIAG_MESSAGE_PRIMARY` (integer)

  Passed to pg_result_error_field(). The primary human-readable error message (typically one line). Always present.

`PGSQL_DIAG_MESSAGE_DETAIL` (integer)

  Passed to pg_result_error_field(). Detail: an optional secondary error message carrying more detail about the problem. May run to multiple lines.

`PGSQL_DIAG_MESSAGE_HINT` (integer)

  Passed to pg_result_error_field(). Hint: an optional suggestion what to do about the problem. This is intended to differ from detail in that it offers advice (potentially inappropriate) rather than hard facts. May run to multiple lines.

`PGSQL_DIAG_STATEMENT_POSITION` (integer)

  Passed to pg_result_error_field(). A string containing a decimal integer indicating an error cursor position as an index into the original statement string. The first character has index 1, and positions are measured in characters not bytes.

`PGSQL_DIAG_INTERNAL_POSITION` (integer)

  Passed to pg_result_error_field(). This is defined the same as the `PG_DIAG_STATEMENT_POSITION` field, but it is used when the cursor position refers to an internally generated command rather than the one submitted by the client. The `PG_DIAG_INTERNAL_QUERY` field will always appear when this field appears.

`PGSQL_DIAG_INTERNAL_QUERY` (integer)

  Passed to pg_result_error_field(). The text of a failed internally-generated command. This could be, for example, a SQL query issued by a PL/pgSQL function.

`PGSQL_DIAG_CONTEXT` (integer)

  Passed to pg_result_error_field(). An indication of the context in which the error occurred. Presently this includes a call stack traceback of active procedural language functions and internally-generated queries. The trace is one entry per line, most recent first.

`PGSQL_DIAG_SOURCE_FILE` (integer)

  Passed to pg_result_error_field(). The file name of the PostgreSQL source-code location where the error was reported.

`PGSQL_DIAG_SOURCE_LINE` (integer)

  Passed to pg_result_error_field(). The line number of the PostgreSQL source-code location where the error was reported.

`PGSQL_DIAG_SOURCE_FUNCTION` (integer)

  Passed to pg_result_error_field(). The name of the PostgreSQL source-code function reporting the error.

`PGSQL_ERRORS_TERSE` (integer)

  Passed to pg_set_error_verbosity(). Specified that returned messages include severity, primary text, and position only; this will normally fit on a single line.

`PGSQL_ERRORS_DEFAULT` (integer)

  Passed to pg_set_error_verbosity(). The default mode produces messages that include the above plus any detail, hint, or context fields (these may span multiple lines).

`PGSQL_ERRORS_VERBOSE` (integer)

  Passed to pg_set_error_verbosity(). The verbose mode includes all available fields.

`PGSQL_STATUS_LONG` (integer)

  Passed to pg_result_status(). Indicates that numerical result code is desired.

`PGSQL_STATUS_STRING` (integer)

  Passed to pg_result_status(). Indicates that textual result command tag is desired.

`PGSQL_CONV_IGNORE_DEFAULT` (integer)

  Passed to pg_convert(). Ignore default values in the table during conversion.

`PGSQL_CONV_FORCE_NULL` (integer)

  Passed to pg_convert(). Use SQL `NULL` in place of an empty string.

`PGSQL_CONV_IGNORE_DEFAULT` (integer)

  Passed to pg_convert(). Ignore conversion of `NULL` into SQL `NOT NULL` columns.

# Примечания

> Замечание: 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.

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

> Замечание: 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 ("").

> Замечание: 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.

# Примеры

This simple example shows how to connect, execute a query, print resulting rows and disconnect from a PostgreSQL database.

Пример 1. PostgreSQL extension overview example

`<?php
// Connecting, selecting database
$dbconn = pg_connect("host=localhost dbname=publishing user=www password=foo")
or die('Could not connect: ' . pg_last_error());
// Performing SQL query
$query = 'SELECT * FROM authors';
$result = pg_query($query) or die('Query failed: ' . pg_last_error());
// Printing results in HTML
echo "<table>\n";
while ($line = pg_fetch_array($result, null, PGSQL_ASSOC)) {
echo "\t<tr>\n";
foreach ($line as $col_value) {
echo "\t\t<td>$col_value</td>\n";
}
echo "\t</tr>\n";
}
echo "</table>\n";
// Free resultset
pg_free_result($result);
// Closing connection
pg_close($dbconn);
?>`

add a note User Contributed Notes
PostgreSQL Functions
16-Nov-2006 04:30
`Chris KL: Will parse well {"\\"}? The second " will be treat as escaped while it shoudn't...`
20-Oct-2006 10:10
`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';`
Chris KL
10-Nov-2005 05:17
`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 $elements;
}`
1413 at blargh dot com
11-Oct-2005 05:09
`Here is some quick and dirty code to convert Postgres-returned arrays into PHP arrays. There's probably a billion bugs, but since I'm only dealing with variable-depth-and-length arrays of integers, it works for my needs.
Most notably, any data that might have commas in it won't work right...
<?php
function PGArrayToPHPArray($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;
}
?>`
anis_wn at gawab dot com
05-Jun-2005 09:45
`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`
WillowCatkin at hotmail dot com
21-May-2005 06:43
`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;
}
?>`
adaml at mimuw edu pl
02-Oct-2004 06:07
`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");`
raja shahed at christine nothdurfter dot com
16-Jul-2004 11:14
`A very good tutorial for Windows users' is here http://www.sitepoint.com/article/use-postgresql-php-windows. Herr Johan Faxer Shows also how to install Cygwin.`
74012 dot 2773 at compuserve dot com
01-Jul-2004 09:35
`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);
}`
abondi at ijk dot it
26-May-2004 05:11
`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));
}`
fmonteiro11 at hotmail dot com
15-Jan-2004 10:50
`Another good source of knowledge is http://www.faqs.org/docs/ppbook/book1.htm`
daniel at bichara dot com dot br
30-Dec-2002 05:04
`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.`
anonymous at unknown dot com
29-Nov-2002 09:50
`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`
swm at php dot net
21-Aug-2002 08:49
`My talk on PHP and PostgreSQL which I presented at O'Reilly OSCON 2002 is now online.
http://www.alcove.com.au/oreilly/`
mystran at wasteland dot pp dot htv dot fi
03-Feb-2002 07:46
`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.`
saberit at home dot com
15-Sep-2001 02:11
`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'.`
hubert at hubertmuller dot com
09-Jul-2001 04:36
`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).`
passion at monkey dot org
27-Jun-2001 06:53
`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));
}`
!spamcraig at ahdore dot com
15-Apr-2001 01:11
`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.`
bleach at chek dot com
02-Mar-2000 12:36
`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.`
add a note
pg_affected_rows sql_regcase

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