PostgreSQL 函数
注释
注意:
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.
注意:
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 returnfalse
.
注意:
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 ("").
注意:
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.
目录
- pg_affected_rows — 返回受影响的记录数目
- pg_cancel_query — 取消异步查询
- pg_client_encoding — 取得客户端编码方式
- pg_close — 关闭一个 PostgreSQL 连接
- pg_connect_poll — 正在进行尝试轮询 PostgreSQL 链接状态。
- pg_connect — 打开一个 PostgreSQL 连接
- pg_connection_busy — 获知连接是否为忙
- pg_connection_reset — 重置连接(再次连接)
- pg_connection_status — 获得连接状态
- pg_consume_input — Reads input on the connection
- pg_convert — 将关联的数组值转换为适合 SQL 语句的格式。
- pg_copy_from — 根据数组将记录插入表中
- pg_copy_to — 将一个表拷贝到数组中
- pg_dbname — 获得数据库名
- pg_delete — 删除记录
- pg_end_copy — 与 PostgreSQL 后端同步
- pg_escape_bytea — 转义 bytea 类型的二进制数据
- 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 — 转义 text/char 类型的字符串
- 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 — 从结果中提取所有行作为一个数组
- pg_fetch_array — 提取一行作为数组
- pg_fetch_assoc — 提取一行作为关联数组
- pg_fetch_object — 提取一行作为对象
- pg_fetch_result — 从结果资源中返回值
- pg_fetch_row — 提取一行作为枚举数组
- pg_field_is_null — 测试字段是否为 null
- pg_field_name — 返回字段的名字
- pg_field_num — 返回字段的编号
- pg_field_prtlen — 返回打印出来的长度
- pg_field_size — 返回指定字段占用内部存储空间的大小
- 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 — 返回相应字段的类型名称
- pg_flush — 刷新链接中已处理的数据查询
- pg_free_result — 释放查询结果占用的内存
- pg_get_notify — Ping 数据库连接
- pg_get_pid — Ping 数据库连接
- pg_get_result — 取得异步查询结果
- pg_host — 返回和某连接关联的主机名
- pg_insert — 将数组插入到表中
- pg_last_error — 得到某连接的最后一条错误信息
- pg_last_notice — 返回 PostgreSQL 服务器最新一条公告信息
- pg_last_oid — 返回上一个对象的 oid
- pg_lo_close — 关闭一个大型对象
- pg_lo_create — 新建一个大型对象
- pg_lo_export — 将大型对象导出到文件
- pg_lo_import — 将文件导入为大型对象
- pg_lo_open — 打开一个大型对象
- pg_lo_read_all — 读入整个大型对象并直接发送给浏览器
- pg_lo_read — 从大型对象中读入数据
- pg_lo_seek — 移动大型对象中的指针
- pg_lo_tell — 返回大型对象的当前指针位置
- pg_lo_truncate — Truncates a large object
- pg_lo_unlink — 删除一个大型对象
- pg_lo_write — 向大型对象写入数据
- pg_meta_data — 获得表的元数据
- pg_num_fields — 返回字段的数目
- pg_num_rows — 返回行的数目
- pg_options — 获得和连接有关的选项
- pg_parameter_status — Looks up a current parameter setting of the server
- pg_pconnect — 打开一个持久的 PostgreSQL 连接
- pg_ping — Ping 数据库连接
- pg_port — 返回该连接的端口号
- pg_prepare — Submits a request to create a prepared statement with the given parameters, and waits for completion
- pg_put_line — 向 PostgreSQL 后端发送以 NULL 结尾的字符串
- 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 — 执行查询
- pg_result_error_field — Returns an individual field of an error report
- pg_result_error — 获得查询结果的错误信息
- pg_result_seek — 在结果资源中设定内部行偏移量
- pg_result_status — 获得查询结果的状态
- pg_select — 选择记录
- 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 — 发送异步查询
- pg_set_client_encoding — 设定客户端编码
- 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 — 启动一个 PostgreSQL 连接的追踪功能
- pg_transaction_status — Returns the current in-transaction status of the server
- pg_tty — 返回该连接的 tty 号
- pg_unescape_bytea — 取消 bytea 类型中的字符串转义
- pg_untrace — 关闭 PostgreSQL 连接的追踪功能
- pg_update — 更新表
- pg_version — Returns an array with client, protocol and server version (when available)
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User Contributed Notes 18 notes
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);
}
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($phpArr);
}
// Output:
// Array
// (
// [0] => string1
// [1] => string2
// [2] => string,3
// [3] => string 4
// )
// =====
Here is some quick and dirty code to convert Postgres-returned arrays into PHP arrays. There's probably a billion bugs, but since I'm only dealing with variable-depth-and-length arrays of integers, it works for my needs.
Most notably, any data that might have commas in it won't work right...
<?php
function PGArrayToPHPArray($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;
}
?>
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));
}
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'.
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.
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;
}
?>
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';
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
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
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));
}
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.
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.
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;
}
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");
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).
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.