Programming PHP

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automatically assigned unique row identifier) are unavailable. Code that uses the PEAR DB is also typically a little slower than code that uses a database-specific extension. Keep in mind that an abstraction layer like PEAR DB does absolutely nothing when it comes to making sure your actual SQL queries are portable. If your application uses any sort of nongeneric SQL, you’ll have to do significant work to convert your queries from one database to another. For large applications, you should consider writing a functional abstraction layer; that is, for each database your application needs to support, write a set of functions that perform various database actions, such as get_user_record( ), insert_user_record( ), and whatever else you need, then have a configuration option that sets the type of database to which your application is connected. This approach lets you use all the intricacies of each database you choose to support without the performance penalty and limitations of an abstraction layer. For simple applications, we prefer the PEAR DB to the database-specific extensions, not just for portability but also for ease of use. The speed and feature costs are rarely significant enough to force us into using the database-specific extensions. For the most part, the rest of this chapter gives sample code using the PEAR DB abstraction objects. For most databases, you’ll need to recompile PHP with the appropriate database drivers built into it. This is necessary whether or not you use the PEAR DB library. The help information for the configure command in the PHP source distribution gives information on how to build PHP with support for various databases. For example: --with-mysql[=DIR] Include MySQL support. DIR is the MySQL base directory. If unspecified, the bundled MySQL library will be used. --with-oci8[=DIR] Include Oracle-oci8 support. Default DIR is ORACLE_HOME. --with-ibm-db2[=DIR] Include IBM DB2 support. DIR is the DB2 base install directory, defaults to /home/db2inst1/sqllib --with-pgsql[=DIR] Include PostgreSQL support. DIR is the PostgreSQL base install directory, defaults to /usr/local/pgsql. You can’t build PHP with support for a database whose client libraries you don’t have on your system. For example, if you don’t have the Oracle client libraries, you can’t build PHP with support for Oracle databases. Use the phpinfo( ) function to check for database support in your installation of PHP. For instance, if you see a section in the configuration report for MySQL, you know you have MySQL support. Relational Databases and SQL A Relational Database Management System (RDBMS) is a server that manages data for you. The data is structured into tables, where each table has some number of 190 | Chapter 8: Databases This is the Title of the Book, eMatter Edition Copyright © 2002 O’Reilly & Associates, Inc. All rights reserved.
columns, each of which has a name and a type. For example, to keep track of James Bond movies, we might have a “movies” table that records the title (a string), year of release (a number), and the actor who played Bond in each movie (an index into a table of Bond actors). Tables are grouped together into databases, so a James Bond database might have tables for movies, actors playing Bond, and villains. An RDBMS usually has its own user system, which controls access rights for databases (e.g., “user Fred can update database Bond”). PHP communicates with relational databases such as MySQL and Oracle using the Structured Query Language (SQL). You can use SQL to create, modify, and query relational databases. The syntax for SQL is divided into two parts. The first, Data Manipulation Language, or DML, is used to retrieve and modify data in an existing database. DML is remarkably compact, consisting of only four verbs: select, insert, update, and delete. The set of SQL commands, used to create and modify the database structures that hold the data, is known as Data Definition Language, or DDL. The syntax for DDL is not as standardized as that for DML, but as PHP just sends any SQL commands you give it to the database, you can use any SQL commands your database supports. Assuming you have a table called movies, this SQL statement would insert a new row: INSERT INTO movies VALUES(0, 'Moonraker', 1979, 2) This SQL statement inserts a new row but lists the columns for which there are values: INSERT INTO movies (title, year, actor) VALUES ('Octopussy', 1982, 2) To delete all movies from 1979, we could use this SQL statement: DELETE FROM movies WHERE year=1979 To change the year for Octopussy to 1983, use this SQL statement: UPDATE movies SET year=1983 WHERE title='Octopussy' To fetch only the movies made in the 1980s, use: SELECT * FROM movies WHERE year >= 1980 AND year < 1990 You can also specify the fields you want returned. For example: SELECT title, year FROM movies WHERE year >= 1980 AND year < 1990 You can issue queries that bring together information from multiple tables. For example, this query joins together the movie and actor tables to let us see who starred in each movie: SELECT movies.title, movies.year, actors.name FROM movies,actors WHERE movies.star = actors.id AND year >= 1980 AND year < 1990 For more on SQL, see SQL in a Nutshell, by Kevin Kline (O’Reilly). This is the Title of the Book, eMatter Edition Copyright © 2002 O’Reilly & Associates, Inc. All rights reserved. Relational Databases and SQL | 191
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Programming PHP
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Programming PHP by Rasmus Lerdorf a
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Colophon Our look is the result of
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Accessing Individual Characters 79
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Concealing PHP Libraries 293 PHP Co
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clarify the explanations, and the p
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There is a web page for this book,
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Chapter 2 CHAPTER 2 Language Basics
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Comments Comments give information
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*/ echo("l=$l m=$m n=$n\n"); ?> Now
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change. Constants are referred to b
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PHP recognizes floating-point numbe
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• The empty string ("") and the s
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Chapter 6 describes classes and obj
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The old value of $black is lost. In
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update_counter( ); update_counter(
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Table 2-3. PHP operators P A Operat
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The division and multiplication ope
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Autoincrement and Autodecrement Ope
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Bitwise Operators The bitwise opera
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something is true. For example, you
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Because all operators are required
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if The if statement checks the trut
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A switch statement is given an expr
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if ($i == 5) break; // breaks out o
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This program adds the numbers from
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loops, and complain if the file bei
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XML Style Because of the advent of
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and other such niceties. Some will
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Chapter 3 CHAPTER 3 Functions A fun
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Typically, functions return some va
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As we discussed in Chapter 2, the e
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Example 3-5. Doubler redux function
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Missing Parameters PHP lets you be
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Anonymous Functions Some PHP functi
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echo "$who was $where"; Kilroy was
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As a special case, you can put a se
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• A padding specifier denoting th
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Boolean values and NULL are not mea
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Changing Case PHP has several funct
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The quote_style and charset argumen
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Query-string encoding The urlencode
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The comparison operators (=) also w
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The Levenshtein algorithm calculate
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The str_repeat( ) function takes a
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print_r($a);Array ( [0] => Fred [1]
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The c in strcspn( ) stands for comp
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These three kinds of patterns can b
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Subpatterns You can use parentheses
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Table 4-8. POSIX anchors Anchor Mat
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Example 4-1. Credit-card validator
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Character Classes Perl-style regula
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Trailing Options Perl-style regular
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A simple use of positive lookahead
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For example: preg_match('/y.*e$/',
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Pass an array of strings as subject
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Quoting for regular expressions The
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Identifying Elements of an Array Yo
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array is almost always a programmer
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Two or more consecutive commas in t
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echo "true!\n"; } if (array_key_exi
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EXTR_PREFIX_SAME, which says that t
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echo "$key is $value\n"; } 0 is spa
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The default argument, if provided,
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you need to answer questions like
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Example 5-3. Sorting arrays (contin
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Here’s how to randomize the order
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Sets Arrays let you implement the b
Page 139 and 140: Here’s the output from Example 5-
Page 141 and 142: Terminology Everyobject-oriented la
Page 143 and 144: You can use variable variables with
Page 145 and 146: } function set_name ($new_name) { $
Page 147 and 148: The object created bythe Person con
Page 149 and 150: Example 6-1. Displaying all declare
Page 151 and 152: Example 6-2. Object introspection f
Page 153 and 154: Here are some sample classes and ob
Page 155 and 156: PHP has two hooks for objects durin
Page 157 and 158: Example 6-5 shows the file next.php
Page 159 and 160: the request contains a blank line,
Page 161 and 162: SERVER_NAME The hostname, DNS alias
Page 163 and 164: The biggest difference between GET
Page 165 and 166: Figure 7-1. The chunkify form and i
Page 167 and 168: Example 7-4. Temperature conversion
Page 169 and 170: Example 7-6. Multiple selection val
Page 171 and 172: Example 7-8. Sticky multivalued che
Page 173 and 174: Files are stored in the server’s
Page 175 and 176: “me@aol” by requiring an at sig
Page 177 and 178: To mark a document as already expir
Page 179 and 180: A third technique for maintaining s
Page 181 and 182: Example 7-10. Preference selection
Page 183 and 184: Session basics To enable sessions f
Page 185 and 186: Custom storage By default, PHP stor
Page 187 and 188: When a session is completed, the de
Page 189: Chapter 8 CHAPTER 8 Databases PHP h
Page 193 and 194: Figure 8-1. The movie page the data
Page 195 and 196: $db = DB::connect($datasource); if
Page 197 and 198: string(4) "1962" ["name"]=> string(
Page 199 and 200: The executeMultiple( ) method takes
Page 201 and 202: echo "$k"; if (is_array($v)) { a_to
Page 203 and 204: Two HTML forms are needed to popula
Page 205 and 206: Example 8-3. Database connection ab
Page 207 and 208: Example 8-4. Backend administration
Page 209 and 210: Example 8-5. Adding a business (con
Page 211 and 212: Example 8-5. Adding a business (con
Page 213 and 214: The business listings page is illus
Page 215 and 216: The series of requests sent by the
Page 217 and 218: many colors as you need. The latter
Page 219 and 220: image-generating function. Example
Page 221 and 222: Example 9-4. Adding text to an imag
Page 223 and 224: Example 9-6. Displaying vertical Tr
Page 225 and 226: Example 9-8. Caching dynamic button
Page 227 and 228: You can also take this a step furth
Page 229 and 230: For a signed integer, the leftmost
Page 231 and 232: True Color Color Indexes The color
Page 233 and 234: Chapter 10 CHAPTER 10 PDF Adobe’s
Page 235 and 236: Figure 10-1. Hello world in a PDF d
Page 237 and 238: Type, Content-Disposition, and Cont
Page 239 and 240: Example 10-3. Changing the origin (
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Example 10-4. Text alignment within
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Example 10-5. Changing text attribu
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usr/share/fonts FontAFM LuciduxSans
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Adding an image to a PDF document i
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Example 10-8. Nonproportional scali
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Figure 10-9. A sample path The pdf_
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The width and height parameters spe
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Example 10-11. Using a template Th
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Example 10-12. Using bookmarks and
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Example 10-13. Specifying a link (c
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Figure 10-16. Closed note The conte
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In HTML, you often have an open tag
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Example 11-1. Generating an XML doc
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The end element handler is called w
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If your external entity reference h
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characters outside the target encod
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XML_ERROR_BAD_CHAR_REF XML_ERROR_BI
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Figure 11-2. Book details comment).
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Example 11-10. bookparse.xml (conti
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Example 11-12. News XSL transform
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more information). The xmlrpc exten
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equest, but it doesn’t know how t
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Chapter 12 CHAPTER 12 Security PHP
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These directives ensure that PHP er
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Restrict Filesystem Access to a Spe
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function or PHP’s copy( ) functio
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• Any system call (through functi
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You can globally disable particular
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Chapter 13 CHAPTER 13 Application T
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user.template. It uses the {DESTINA
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{ARTICLE} might be useful, as it wo
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} ob_start('rewrite'); ?> Visit our
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To turn off error reporting entirel
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Example 13-5. Log-rolling error han
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Before you begin optimization, ask
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changes you make to your code as yo
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• Only include or require files t
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MySQL replication Sometimes the dat
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Chapter 14 CHAPTER 14 Extending PHP
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examples, and you are strongly enco
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int Integer/long long Same as int a
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zend_module_entry rot13_module_entr
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for(i=0, ch=arg; i= 'A')&&(*ch
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if (extension_loaded($module)) { $s
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SWF_DIR=$i AC_MSG_RESULT(found in $
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If you compile the Apache module ve
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For example: zval **old, *new; *new
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The value returned from a PHP funct
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A More Complex Example Here’s an
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Table 14-4. RETURN-related convenie
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* ... */ }; PHP_MINIT_FUNCTION(foo)
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using SEPARATE_ZVAL( ), initializes
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The struct looks like this in the p
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zend_hash_update(&EG(symbol_table),
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Resources A resource is a generic d
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Chapter 15 CHAPTER 15 PHP on Window
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3. Windows 95/98/Me: the Windows sy
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Then explicitly load the module wit
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un under IIS, you will need to reim
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External Commands PHP uses the defa
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This creates a reference (VT_BYREF)
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Figure 15-3. Gleaning syntax from W
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Now we can complete the invoice wit
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multiple Workbooks, each of which c
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Example 15-4. Querying Excel via OD
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• Applications that want to use t
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Example 15-5. Add new phone number,
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Files, directories, and filesystem
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addcslashes string addcslashes(stri
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array_merge array array_merge(array
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array_search mixed array_search(mix
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asort void asort(array array[, int
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call_user_func mixed call_user_func
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chown bool chown(string path, mixed
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cos double cos(double value) Return
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Any characters in the format string
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each array each(array array) Create
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Any number of these options can be
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fflush int fflush(int handle) Commi
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filemtime int filemtime(string path
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If include is specified and is true
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ftell int ftell(int handle) Returns
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get_current_user string get_current
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get_parent_class string get_parent_
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getmypid int getmypid( ) Returns th
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header void header(string header[,
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implode string implode(array string
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is_double bool is_double(mixed valu
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is_scalar bool is_scalar(mixed valu
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Calculates the Levenshtein distance
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log double log(double number) Retur
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mkdir int mkdir(string path, int mo
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number_format string number_format(
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openlog int openlog(string identity
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parse_url array parse_url(string ur
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phpinfo void phpinfo([int what]) Ou
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printf int printf(string format[, m
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eaddir string readdir(int handle) R
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ound double round(double number[, i
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setlocale string setlocale(mixed ca
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sort void sort(array array[, int fl
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str_pad string str_pad(string strin
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%H Hour in 24-hour format, includin
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strncmp int strncmp(string one, str
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strtr string strtr(string string, s
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tmpfile int tmpfile( ) Creates a te
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unregister_tick_function void unreg
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wordwrap string wordwrap(string str
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old versions of aspell, you should
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DBM For very simple database instal
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Hyperwave Hyperwave is a database f
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mcrypt This extension provides an i
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pdflib pdflib provides support for
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Sybase This extension provides supp
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Symbols & (ampersand) &= (bitwise A
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| (vertical bar) |= (bitwise OR ass
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aspell PHP library, 457 assert() fu
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checksums mhash library, 464 valida
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cryptography mcrypt extension, 464
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DTD (Document Type Definition), 263
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System V Semaphores and Shared memo
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calling, 61 for each array element,
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H hash mark (#) in comments, 19 hea
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interlacing GIF images, 246 interna
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masks, using in string searches, 94
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serialization of, 153-157, 438 _ _s
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pdf_open_file() function, 234 pdf_p
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with echo, 76 with print() function
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S Sablotron C library (XSLT support
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sql_regcase() function, 443 sqrt()
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tan() function, 451 target encoding
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function parameters, 33 functions f
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xml_set_unparsed_entity_decl_handle
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