http://www.zfconf.ru/2012/talks/ibm-db2-embedded-sql-for-php-implementation/

1. IBM DB2 Embedded SQL for PHP
Александр Веремьев
cawaspb@gmail.com

2. Что такое
встраиваемый SQL
?????

3. $dbname = 'db_name';
$dbuser = 'username';
$dbpwd = 'password';
EXEC SQL connect to :$dbname user :$dbuser using :$dbpwd;
...
$userid = $_POST['userid'];
$password = $_POST['password'];
EXEC SQL select firstname, lastname
into :$firstname, :$lastname
from users
where login = :$userid AND password = :$password;
if ($SQLCODE == 100 /* NOT FOUND */) {
echo "Wrong login/password combination.n";
} else {
echo $firstname . "n"
. $lastname . "n";
}

4. EXEC SQL DECLARE c1 CURSOR for
select id, time, subject, message
from emails
where userid = :$userid AND status = 'NEW';
EXEC SQL BEGIN DECLARE SECTION;
INTEGER $email_id;
TMESTAMP $time;
VARCHAR(256) $subject;
CLOB(16M) $message_body;
EXEC SQL END DECLARE SECTION;
EXEC SQL OPEN c1;
EXEC SQL FETCH c1 into :$email_id, :$time, :$subject, :$message_body;
while ($SQLCODE != 100 /* NOT FOUND */) {
// process message
...
EXEC SQL FETCH c1 into :$email_id, :$time, :$subject, :$message_body;
}

5. Часть SQL-92 стандарта
Непосредственная поддержка со стороны СУБД в тех или иных
языках:
- IBM DB2 (C/C++, Java, COBOL, FORTRAN, REXX)
- Oracle (Ada, C/C++, COBOL, FORTRAN, Pascal, PL/I)
- PostgreSQL (C/C++, COBOL)
- Microsof SQL Server (COBOL)
- MySQL (COBOL)
- Sybase
-…

6. IBM DB2 Embedded SQL for PHP support:
PHP extension db2_embsql
db2_embsql_precompile($input_file, $dbname, $options_string);
db2_embsql_precompile_string($php_code, $dbname, $options_string);

7. Особенности реализации встроенного SQL в IBM DB2.
Static SQL.
<?php <?php
/** /**
* Zend Framework * Zend Framework
* *
* LICENSE * LICENSE
* *
* This source file is subject to the new BSD license that is bundled * This source file is subject to the new BSD license that is bundled
* with this package in the file LICENSE.txt. * with this package in the file LICENSE.txt.
* It is also available through the world-wide-web at this URL: * It is also available through the world-wide-web at this URL:
* http://framework.zend.com/license/new-bsd * http://framework.zend.com/license/new-bsd
* If you did not receive a copy of the license and are unable to * If you did not receive a copy of the license and are unable to
* obtain it through the world-wide-web, please send an email * obtain it through the world-wide-web, please send an email
* to license@zend.com so we can send you a copy immediately. * to license@zend.com so we can send you a copy immediately.
* *
* @category Zend * @category Zend
* @package Zend_Pdf * @package Zend_Pdf
* @copyright Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com) * @copyright Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License * @license http://framework.zend.com/license/new-bsd New BSD License
* @version $Id: Pdf.php 22908 2010-08-25 20:52:47Z alexander $ * @version $Id: Pdf.php 22908 2010-08-25 20:52:47Z alexander $
*/ */
/** User land classes and interfaces turned on by Zend/Pdf.php file inclusion. */
DB2
/** User land classes and interfaces turned on by Zend/Pdf.php file inclusion. */
/** @todo Section should be removed with ZF 2.0 release as obsolete */ /** @todo Section should be removed with ZF 2.0 release as obsolete */
/** Zend_Pdf_Page */ /** Zend_Pdf_Page */
require_once 'Zend/Pdf/Page.php'; require_once 'Zend/Pdf/Page.php';
/** Zend_Pdf_Canvas */ /** Zend_Pdf_Canvas */
require_once 'Zend/Pdf/Canvas.php'; require_once 'Zend/Pdf/Canvas.php';
/** Internally used classes */ /** Internally used classes */
require_once 'Zend/Pdf/Element/Dictionary.php'; require_once 'Zend/Pdf/Element/Dictionary.php';
require_once 'Zend/Pdf/Element/Name.php'; require_once 'Zend/Pdf/Element/Name.php';
require_once 'Zend/Pdf/Element/Null.php'; require_once 'Zend/Pdf/Element/Null.php';
require_once 'Zend/Pdf/Element/Numeric.php'; require_once 'Zend/Pdf/Element/Numeric.php';
require_once 'Zend/Pdf/Element/String.php'; require_once 'Zend/Pdf/Element/String.php';
/** /**
* General entity which describes PDF document. * General entity which describes PDF document.
* It implements document abstraction with a document level operations. * It implements document abstraction with a document level operations.
* *
* Class is used to create new PDF document or load existing document. * Class is used to create new PDF document or load existing document.
* See details in a class constructor description * See details in a class constructor description
* *
* Class agregates document level properties and entities (pages, bookmarks, * Class agregates document level properties and entities (pages, bookmarks,
* document level actions, attachments, form object, etc) * document level actions, attachments, form object, etc)
* *
* @category Zend * @category Zend
* @package Zend_Pdf * @package Zend_Pdf
* @copyright Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com) * @copyright Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License * @license http://framework.zend.com/license/new-bsd New BSD License
*/ */
class Zend_Pdf class Zend_Pdf
{ {
/**** Class Constants ****/ /**** Class Constants ****/
/** /**
* Version number of generated PDF documents. * Version number of generated PDF documents.
*/ */
const PDF_VERSION = '1.4'; const PDF_VERSION = '1.4';
/** /**
* PDF file header. * PDF file header.
*/ */
const PDF_HEADER = "%PDF-1.4n%xE2xE3xCFxD3n";
/** * * *
* Pages collection
* /**
* @todo implement it as a class, which supports ArrayAccess and Iterator interfaces, * Set user defined memory manager
* to provide incremental parsing and pages tree updating. *
* That will give good performance and memory (PDF size) benefits. * @param Zend_Memory_Manager $memoryManager
* */
* @var array - array of Zend_Pdf_Page object static public function setMemoryManager(Zend_Memory_Manager $memoryManager)
*/ {
public $pages = array(); self::$_memoryManager = $memoryManager;
/** }
* List of inheritable attributesfor pages tree }
*
* @var array
*/
protected static $_inheritableAttributes = array('Resources', 'MediaBox', 'CropBox', 'Rotate');
/**
* Request used memory manager
*
* @return Zend_Memory_Manager
*/
static public function getMemoryManager()
{
if (self::$_memoryManager === null) {
require_once 'Zend/Memory.php';
self::$_memoryManager = Zend_Memory::factory('none');
}
return self::$_memoryManager;
}
/**
* Set user defined memory manager
*
* @param Zend_Memory_Manager $memoryManager
*/
static public function setMemoryManager(Zend_Memory_Manager $memoryManager)
{
self::$_memoryManager = $memoryManager;
}
/**
* Set the document-level JavaScript
*
* @param string $javascript
*/
public function setJavaScript($javascript)
{
$this->_javaScript = $javascript;
}
/**
* Convert date to PDF format (it's close to ASN.1 (Abstract Syntax Notation
* One) defined in ISO/IEC 8824).
*
* @todo This really isn't the best location for this method. It should
* probably actually exist as Zend_Pdf_Element_Date or something like that.
*
* @todo Address the following E_STRICT issue:
* PHP Strict Standards: date(): It is not safe to rely on the system's
.BND
* timezone settings. Please use the date.timezone setting, the TZ
* environment variable or the date_default_timezone_set() function. In
* case you used any of those methods and you are still getting this
* warning, you most likely misspelled the timezone identifier.
*
* @param integer $timestamp (optional) If omitted, uses the current time.
* @return string
*/
public static function pdfDate($timestamp = null)
{
if ($timestamp === null) {
$date = date('D:YmdHisO');
} else {
$date = date('D:YmdHisO', $timestamp);
}
return substr_replace($date, ''', -2, 0) . ''';
}
}

8. <?php
/**
* Zend Framework
*
* LICENSE
*
* This source file is subject to the new BSD license that is bundled
* with this package in the file LICENSE.txt.
* It is also available through the world-wide-web at this URL:
* http://framework.zend.com/license/new-bsd
* If you did not receive a copy of the license and are unable to
* obtain it through the world-wide-web, please send an email
* to license@zend.com so we can send you a copy immediately.
PHP код
*
PHP код
* @category Zend
* @package Zend_Pdf
* @copyright Copyright (c) 2005-2010 Zend Technologies USA Inc.
(http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @version $Id: Pdf.php 22908 2010-08-25 20:52:47Z alexander $
*/
/** User land classes and interfaces turned on by Zend/Pdf.php file inclusion. */
/** @todo Section should be removed with ZF 2.0 release as obsolete */
/** Zend_Pdf_Page */
require_once 'Zend/Pdf/Page.php';
/** Zend_Pdf_Canvas */
require_once 'Zend/Pdf/Canvas.php';
/** Internally used classes */
require_once 'Zend/Pdf/Element/Dictionary.php';
require_once 'Zend/Pdf/Element/Name.php';
require_once 'Zend/Pdf/Element/Null.php';
require_once 'Zend/Pdf/Element/Numeric.php';
require_once 'Zend/Pdf/Element/String.php';
/**
* General entity which describes PDF document.
* It implements document abstraction with a document level operations.
*
* Class is used to create new PDF document or load existing document.
* See details in a class constructor description
*
* Class agregates document level properties and entities (pages, bookmarks,
* document level actions, attachments, form object, etc)
*
* @category Zend
* @package Zend_Pdf
* @copyright Copyright (c) 2005-2010 Zend Technologies USA Inc.
(http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
*/
class Zend_Pdf
{
/**** Class Constants ****/
/**
* Version number of generated PDF documents.
*/
const PDF_VERSION = '1.4';
/**
* PDF file header.
*/
const PDF_HEADER = "%PDF-1.4n%xE2xE3xCFxD3n";
/**
* Pages collection
*
* @todo implement it as a class, which supports ArrayAccess and Iterator
interfaces,
* to provide incremental parsing and pages tree updating.
* That will give good performance and memory (PDF size) benefits.
*
* @var array - array of Zend_Pdf_Page object
*/
public $pages = array();
/**
* List of inheritable attributesfor pages tree
*
* @var array
*/
protected static $_inheritableAttributes = array('Resources', 'MediaBox',
'CropBox', 'Rotate');
/**
* Request used memory manager
*
* @return Zend_Memory_Manager
*/
static public function getMemoryManager()
{
if (self::$_memoryManager === null) {
require_once 'Zend/Memory.php';
self::$_memoryManager = Zend_Memory::factory('none');
}
return self::$_memoryManager;
}
/**
* Set user defined memory manager
*
* @param Zend_Memory_Manager $memoryManager
*/
static public function setMemoryManager(Zend_Memory_Manager $memoryManager)
{
self::$_memoryManager = $memoryManager;
}
/**
* Set the document-level JavaScript
*
* @param string $javascript
*/
public function setJavaScript($javascript)
{
$this->_javaScript = $javascript;
}
/**
* Convert date to PDF format (it's close to ASN.1 (Abstract Syntax Notation
SQL
* One) defined in ISO/IEC 8824).
*
* @todo This really isn't the best location for this method. It should
* probably actually exist as Zend_Pdf_Element_Date or something like that.
Компиляция
*
* @todo Address the following E_STRICT issue:
* PHP Strict Standards: date(): It is not safe to rely on the system's
* timezone settings. Please use the date.timezone setting, the TZ
* environment variable or the date_default_timezone_set() function. In
* case you used any of those methods and you are still getting this
* warning, you most likely misspelled the timezone identifier.
*
* @param integer $timestamp (optional) If omitted, uses the current time.
* @return string
*/
public static function pdfDate($timestamp = null)
{
if ($timestamp === null) {
$date = date('D:YmdHisO');
} else {
$date = date('D:YmdHisO', $timestamp);
}
return substr_replace($date, ''', -2, 0) . ''';
}
}

9. Статический SQL.
- отсутствие повторной компиляции, использование готового плана
выполнения (отличные результаты на OLTP нагрузке);
- защита от SQL injection;
- улучшенная модель security.

10. Связывание типов.
PHP SQL
- динамическая типизация - статическая типизация
- слабая типизация - строгая типизация1
1
поддерживается неявный кастинг для некоторого подмножества
типов.

11. Связывание типов.
PHP SQL
$var1 (integer)
SELECT … INTO :$var1 …
…
$var1 (string)
INSERT INTO … VALUES(:$var1, …)
$var2 (float)
SELECT … WHERE COL1 > :$var2
$var1 (string)

12. Связывание типов, C/C++:
EXEC SQL BEGIN DECLARE SECTION;
char dbName[16];
char userid[30];
char passwd[30];
SQL TYPE IS CLOB(2M) img_data;
EXEC SQL END DECLARE SECTION;
...
EXEC SQL CONNECT TO :dbName USER :userid USING :passwd;

13. db2_embsql extension:
1. Декларативность секции
EXEC SQL BEGIN DECLARE SECTION;
…
EXEC SQL END DECLARE SECTION;
2. Физическое размещение HV в модуле extension’а.

14. 3. Маппинг имѐн host variables (и производных lvalue конструкций)
на внутренние имена HV в SQL выражениях, отправляемых на
прекомпиляцию.
$this->myCoolVariable
$values[$index]->val
$options['my_cool_option']
…

15. Маппинг типов:
SMALLINT (16-bit integer) - integrer
INTEGER (32-bit integer) - integrer
BIGINT (64-bit integer) - integrer
REAL - float
DOUBLE - float
DECIMAL - STRING
CHAR(n) - STRING
CHAR(n) FOR BIT DATA - STRING
VARCHAR(n) - STRING
CLOB(n) - STRING
BLOB(n) - STRING
DATE - STRING
TIME - STRING
TIMESTAMP - STRING
...

16. Решение проблемы предугадывания типов, input/output variables:
EXEC SQL SELECT LOGIN, FIRSTNAME, LASTNAME
INTO :$login, :$firstname, :$lastname
FROM USERS
WHERE ID = :$user_id;
vs
EXEC SQL INSERT INTO USERS
VALUES( :$login, :$firstname, :$lastname);

17. Декларация “базовых” переменных:
EXEC SQL BEGIN DECLARE SECTION;
VARCHAR(32) $login;
VARCHAR(64) $firstname,
VARCHAR(64) $lastname;
EXEC SQL BEGIN DECLARE SECTION;
...
$login = $this->login;
$firstname = $this->firstname;
$lastname = $this->lastname;
EXEC SQL INSERT INTO USERS
VALUES(:$login, :$firstname, :$lastname);

18. Декларация “производных” переменных:
EXEC SQL BEGIN DECLARE SECTION;
VARCHAR(32) $this->login;
VARCHAR(64) $this->firstname,
VARCHAR(64) $this->lastname;
EXEC SQL BEGIN DECLARE SECTION;
...
EXEC SQL INSERT INTO USERS
VALUES( :$this->login,
:$this->firstname,
:$this->lastname);

19. Как работают вызовы SQL statements:
<?php
/**
* Zend Framework
*
DB2 Run Database
* LICENSE
*
* This source file is subject to the new BSD license that is bundled
* with this package in the file LICENSE.txt.
* It is also available through the world-wide-web at this URL:
* http://framework.zend.com/license/new-bsd
Time Services Manager
SELECT …
* If you did not receive a copy of the license and are unable to
* obtain it through the world-wide-web, please send an email
* to license@zend.com so we can send you a copy immediately.
*
* @category Zend
* @package Zend_Pdf
* @copyright Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @version $Id: Pdf.php 22908 2010-08-25 20:52:47Z alexander $
*/
/** User land classes and interfaces turned on by Zend/Pdf.php file inclusion. */
/** @todo Section should be removed with ZF 2.0 release as obsolete */
/** Zend_Pdf_Page */
require_once 'Zend/Pdf/Page.php';
/** Zend_Pdf_Canvas */
require_once 'Zend/Pdf/Canvas.php';
/** Internally used classes */
require_once 'Zend/Pdf/Element/Dictionary.php';
require_once 'Zend/Pdf/Element/Name.php';
:HV1
require_once 'Zend/Pdf/Element/Null.php';
require_once 'Zend/Pdf/Element/Numeric.php';
require_once 'Zend/Pdf/Element/String.php';
/**
* General entity which describes PDF document.
* It implements document abstraction with a document level operations.
*
* Class is used to create new PDF document or load existing document.
* See details in a class constructor description
*
* Class agregates document level properties and entities (pages, bookmarks,
:HV2
* document level actions, attachments, form object, etc)
*
* @category Zend
* @package Zend_Pdf
* @copyright Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
*/
class Zend_Pdf
{
/**** Class Constants ****/
/**
* Version number of generated PDF documents.
*/
const PDF_VERSION = '1.4';
/**
* PDF file header.
CALL
*/
const PDF_HEADER = "%PDF-1.4n%xE2xE3xCFxD3n";
/**
* Pages collection
*
* @todo implement it as a class, which supports ArrayAccess and Iterator interfaces,
* to provide incremental parsing and pages tree updating.
* That will give good performance and memory (PDF size) benefits.
*
* @var array - array of Zend_Pdf_Page object
*/
public $pages = array();
/**
Packages
* List of inheritable attributesfor pages tree
Packages
*
Packages
* @var array
*/
protected static $_inheritableAttributes = array('Resources', 'MediaBox', 'CropBox', 'Rotate');
/**
* Request used memory manager
*
* @return Zend_Memory_Manager
*/
static public function getMemoryManager()
{
if (self::$_memoryManager === null) {
require_once 'Zend/Memory.php';
self::$_memoryManager = Zend_Memory::factory('none');
}
return self::$_memoryManager;
}
/**
* Set user defined memory manager
*
* @param Zend_Memory_Manager $memoryManager
*/
static public function setMemoryManager(Zend_Memory_Manager $memoryManager)
{
self::$_memoryManager = $memoryManager;
}
/**
* Set the document-level JavaScript
*
* @param string $javascript
*/
public function setJavaScript($javascript)
{
$this->_javaScript = $javascript;
}
/**
* Convert date to PDF format (it's close to ASN.1 (Abstract Syntax Notation
* One) defined in ISO/IEC 8824).
*
Data
* @todo This really isn't the best location for this method. It should
Packages
* probably actually exist as Zend_Pdf_Element_Date or something like that.
Packages
*
* @todo Address the following E_STRICT issue:
* PHP Strict Standards: date(): It is not safe to rely on the system's
* timezone settings. Please use the date.timezone setting, the TZ
* environment variable or the date_default_timezone_set() function. In
* case you used any of those methods and you are still getting this
* warning, you most likely misspelled the timezone identifier.
*
* @param integer $timestamp (optional) If omitted, uses the current time.
* @return string
*/
public static function pdfDate($timestamp = null)
{
if ($timestamp === null) {
$date = date('D:YmdHisO');
} else {
Result
$date = date('D:YmdHisO', $timestamp);
}
return substr_replace($date, ''', -2, 0) . ''';
}
}
:HV3

20. пример прекомпилированного С кода:
/*
EXEC SQL select count(*) into :tbl_cnt from syscat.tables;
*/
{
#line 39 "dbconn.sqc"
sqlastrt(sqla_program_id, &sqla_rtinfo, &sqlca);
#line 39 "dbconn.sqc"
sqlaaloc(3,1,2,0L);
{
struct sqla_setdata_list sql_setdlist[1];
#line 39 "dbconn.sqc"
sql_setdlist[0].sqltype = 496; sql_setdlist[0].sqllen = 4;
#line 39 "dbconn.sqc"
sql_setdlist[0].sqldata = (void*)&tbl_cnt;
#line 39 "dbconn.sqc"
sql_setdlist[0].sqlind = 0L;
#line 39 "dbconn.sqc"
sqlasetdata(3,0,1,sql_setdlist,0L,0L);
}

21. #line 39 "dbconn.sqc"
sqlacall((unsigned short)24,1,0,3,0L);
#line 39 "dbconn.sqc"
sqlastop(0L);
}
#line 39 "dbconn.sqc"
EMB_SQL_CHECK("Count tables");
printf("select count(*) from syscat.tables;n--------n %dn", tbl_cnt);

22. Архитектура extension’а как магазинного автомата:
Очередь вызовов
PHP engine
<?php
/**
* Zend Framework
*
DB2_ESQL
* LICENSE
*
* This source file is subject to the new BSD license that is bundled
* with this package in the file LICENSE.txt.
* It is also available through the world-wide-web at this URL:
* http://framework.zend.com/license/new-bsd
* If you did not receive a copy of the license and are unable to
* obtain it through the world-wide-web, please send an email
* to license@zend.com so we can send you a copy immediately.
extension
*
* @category Zend
* @package Zend_Pdf
* @copyright Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @version $Id: Pdf.php 22908 2010-08-25 20:52:47Z alexander $
*/
/** User land classes and interfaces turned on by Zend/Pdf.php file inclusion. */
/** @todo Section should be removed with ZF 2.0 release as obsolete */
/** Zend_Pdf_Page */
require_once 'Zend/Pdf/Page.php';
/** Zend_Pdf_Canvas */
require_once 'Zend/Pdf/Canvas.php';
/** Internally used classes */
require_once 'Zend/Pdf/Element/Dictionary.php';
/**
* General entity which describes PDF document.
* It implements document abstraction with a document level operations.
*
* Class is used to create new PDF document or load existing document.
sqlaaloc(...)
* See details in a class constructor description
*
*
* @category
* @package
Zend
Zend_Pdf
* @copyright Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
sqlacall(...)
* @license http://framework.zend.com/license/new-bsd New BSD License
{
*/
class Zend_Pdf
/**** Class Constants ****/
/**
sqlacmpd(...)
* Version number of generated PDF documents.
*/
const PDF_VERSION = '1.4';
/**
* PDF file header.
*/
sqladloc(...)
const PDF_HEADER = "%PDF-1.4n%xE2xE3xCFxD3n";
/**
/**
* List of inheritable attributesfor pages tree
*
* @var array
sqlastls(...)
*/
protected static $_inheritableAttributes = array('Resources', 'MediaBox',
'CropBox', 'Rotate');
/**
* Request used memory manager
*
sqlastlv(...)
* @return Zend_Memory_Manager
{
*/
static public function getMemoryManager()
if (self::$_memoryManager === null) {
require_once 'Zend/Memory.php';
sqlastlva(...)
self::$_memoryManager = Zend_Memory::factory('none');
}
/**
}
return self::$_memoryManager;
* Set user defined memory manager
sqlasetdata(...)
*
* @param Zend_Memory_Manager $memoryManager
*/
static public function setMemoryManager(Zend_Memory_Manager $memoryManager)
{
self::$_memoryManager = $memoryManager;
sqlastop(...)
}
/**
* Set the document-level JavaScript
*
* @param string $javascript
*/
sqlastrt(...)
public function setJavaScript($javascript)
{
}
/**
$this->_javaScript = $javascript;
* Convert date to PDF format (it's close to ASN.1 (Abstract Syntax Notation
sqlausda(...)
* One) defined in ISO/IEC 8824).
*
* @todo This really isn't the best location for this method. It should
* probably actually exist as Zend_Pdf_Element_Date or something like that.
*
* @todo Address the following E_STRICT issue:
* PHP Strict Standards: date(): It is not safe to rely on the system's
* timezone settings. Please use the date.timezone setting, the TZ
* environment variable or the date_default_timezone_set() function. In
* case you used any of those methods and you are still getting this
* warning, you most likely misspelled the timezone identifier.
*
* @param integer $timestamp (optional) If omitted, uses the current time.
* @return string
*/
public static function pdfDate($timestamp = null)
{
if ($timestamp === null) {
$date = date('D:YmdHisO');
} else {
$date = date('D:YmdHisO', $timestamp);
}
return substr_replace($date, ''', -2, 0) . ''';
НV area
}
}

23. Плюсы:
- cтатичность SQL;
- отсутствие фазы компиляции запроса на этапе выполнения;
- отсутствие фазы построения плана запроса на этапе выполнения;
- проверка SQL на этапе прекомпиляции;
- защищѐнность от вымывания кэшей SQL запросов;
- управляемость планов выполнения, возможность вести
сравнительную статистику по изменяемости планов
по модулям приложений, пакет как measurement объѐмов и
характера данных в проекции приложения;
- модель security – права на выполнение на уровне пакета.

24. Минусы:
- cтатичность SQL;
- дополнительная фаза - прекомпиляция;
- необходимость существования соответствующих объектов
базы на момент компиляции;
- прирост производительности незаметен на длительных
запросах (10 и более секунд);
- слабая ориентированность на “ad hoc” запросы:
имеется поддержка динамического SQL, но она ничем
не лучше native подходов с помощью odbc/cli;
- отсутствие выигрыша для редко выполняемых запросов.

25. Ограничения embedded SQL:
- невозможность использования Host variables в именах
объектов имѐн таблиц, функций, процедур, …, кроме как
при использовании динамического SQL (PREPAPRE, EXECUTE);
- невозможность использования scrollable курсоров;

26. IBM DB2 и динамический SQL для PHP:
http://publib.boulder.ibm.com/infocenter/db2luw/v9r7/topic/com.ibm.swg.im.dbclient.php.doc/doc/c0021523.html
1. ibm_db2 extension
http://www.php.net/manual/en/book.ibm-db2.php
2. pdo_ibm driver
http://www.php.net/manual/en/book.pdo.php
3. Unified odbc extension
http://www.php.net/manual/en/book.uodbc.php

27. Способы увеличения производительности динамического SQL:
- увеличение размера STATEMENT CACHE – pckachesz
имеется некоторая точка насыщения, предмет для мониторинга:
* pkg_cache_lookups (package cache lookups)
* pkg_cache_inserts (package cache inserts)
* pkg_cache_size_top (package cache high water mark)
* pkg_cache_num_overflows (package cache overflows)
- использование параметризованных запросов
есть “Но” – план выполнения будет строиться без учѐта реального
значения параметра
- StmtConcentrator CLI/ODBC параметр

28. - конвертирование динамического SQL в статический:
1. Коллектор запросов (CLI/ODBC параметры):
STATICMODE=CAPTURE
STATICCAPFILE=<path>
STATICPACKAGE=<package_schema>.<package_name>
2. Работа приложения
3. db2cap bind …
4. STATICMODE=MATCH

29. Планы
- Пре-релиз конец мая – начало июня.
- Релиз, передача в Open Source – конец июня.

30. Embedded SQL
vs
ORM frameworks/ActiveRecord
???

31. Вопросы
Александр Веремьев
cawaspb@gmail.com