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https://github.com/sigmasternchen/php-doc-en
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git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@180160 c90b9560-bf6c-de11-be94-00142212c4b1
297 lines
9.5 KiB
XML
297 lines
9.5 KiB
XML
<?xml version='1.0' encoding='iso-8859-1'?>
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<!-- $Revision: 1.11 $ -->
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<refentry id="function.PDO-construct">
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<refnamediv>
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<refname>PDO::__construct</refname>
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<refpurpose>
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Creates a PDO instance representing a connection to a database
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</refpurpose>
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</refnamediv>
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<refsect1 role="description">
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&reftitle.description;
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<methodsynopsis>
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<type>PDO</type><methodname>PDO::__construct</methodname>
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<methodparam><type>string</type><parameter>dsn</parameter></methodparam>
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<methodparam choice="opt"><type>string</type><parameter>username</parameter></methodparam>
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<methodparam choice="opt"><type>string</type><parameter>password</parameter></methodparam>
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<methodparam choice="opt"><type>array</type><parameter>driver_options</parameter></methodparam>
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</methodsynopsis>
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&warn.experimental.func;
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<para>
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Creates a PDO instance to represent a connection to the requested
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database.
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</para>
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</refsect1>
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<refsect1 role="parameters">
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&reftitle.parameters;
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<para>
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<variablelist>
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<varlistentry><term>dsn</term>
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<listitem>
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<para>
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The Data Source Name, or DSN, contains the information required to
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connect to the database.
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</para>
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<para>
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In general, a DSN consists of the PDO driver name, followed by a colon,
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followed by the PDO driver-specific connection syntax. Examples of each
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driver are given below:
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</para>
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<para>
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<variablelist>
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<varlistentry>
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<term><constant>PDO_DBLIB</constant></term>
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<listitem>
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<para>
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The DSN prefix is either <userinput>sybase:</userinput>
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or <userinput>mssql:</userinput> depending on which libraries
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it was linked against during compilation.
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</para>
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<para><userinput>sybase:host=localhost; dbname=testdb</userinput></para>
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<para><userinput>mssql:host=localhost; dbname=testdb</userinput></para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>PDO_FIREBIRD</constant></term>
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<listitem>
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<para><userinput>firebird:User=john;Password=mypass;Database=DATABASE.GDE;DataSource=localhost;Port=3050</userinput></para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>PDO_MYSQL</constant></term>
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<listitem>
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<para><userinput>mysql:host=localhost;dbname=testdb</userinput></para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>PDO_OCI</constant></term>
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<listitem>
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<para>To connect via <filename>tnsnames.ora</filename>, use:</para>
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<para><userinput>oci:mydb</userinput></para>
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<para>If using instantclient, use:</para>
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<para><userinput>oci:dbname=//localhost:1521/testdb</userinput></para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>PDO_ODBC</constant></term>
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<listitem>
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<para><userinput>odbc:DSN=SAMPLE;UID=john;PWD=mypass</userinput></para>
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<para>DSN=SAMPLE refers to the SAMPLE data source configured in the ODBC driver manager.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>PDO_PGSQL</constant></term>
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<listitem>
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<para><userinput>pgsql:host=localhost port=5432 dbname=testdb user=john password=mypass</userinput></para>
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<para>
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Note, by passing <varname>user</varname> and <varname>password</varname>
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in the DSN, the <parameter>username</parameter>
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and <parameter>password</parameter> parameters become optional.
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If specified, they are glued to the end of the connection string.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>PDO_SQLITE</constant></term>
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<listitem>
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<para><userinput>sqlite:/path/to/database</userinput></para>
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<para>To create a database in memory, use:</para>
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<para><userinput>sqlite::memory:</userinput></para>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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<para>
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The <parameter>dsn</parameter> parameter supports three
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different methods of specifying the arguments required to create
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a database connection:
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</para>
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<para>
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<variablelist>
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<varlistentry><term>Driver invocation</term>
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<listitem>
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<para>
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<parameter>dsn</parameter> contains the full DSN.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry><term>URI invocation</term>
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<listitem>
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<para>
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<parameter>dsn</parameter> consists of <userinput>uri:</userinput>
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followed by a URI that defines the location of a file containing
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the DSN string. The URI can specify a local file or a remote URL.
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</para>
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<para><userinput>uri:file:///path/to/dsnfile</userinput></para>
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</listitem>
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</varlistentry>
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<varlistentry><term>Aliasing</term>
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<listitem>
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<para>
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<parameter>dsn</parameter> consists of a name
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<parameter>name</parameter> that maps to
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<literal>pdo.dsn.<parameter>name</parameter></literal> in &php.ini;
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defining the DSN string.
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</para>
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<note>
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<para>
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The alias must be defined in &php.ini;, and not &htaccess; or &httpd.conf;
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</para>
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</note>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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</listitem>
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</varlistentry>
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<varlistentry><term>username</term>
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<listitem>
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<para>
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The user name for the DSN string. This parameter is optional for
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some PDO drivers.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry><term>password</term>
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<listitem>
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<para>
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The password for the DSN string. This parameter is optional for
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some PDO drivers.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry><term>driver_options</term>
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<listitem>
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<para>
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A key=>value array of driver-specific connection options.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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</refsect1>
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<refsect1 role="returnvalues">
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&reftitle.returnvalues;
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<para>
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Returns a PDO object on success.
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</para>
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</refsect1>
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<refsect1 role="exceptions">
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&reftitle.exceptions;
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<para>
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<function>PDO::construct</function> throws a PDOException if the attempt
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to connect to the requested database fails.
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</para>
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</refsect1>
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<refsect1 role="examples">
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&reftitle.examples;
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<para>
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<example><title>Create a PDO instance via driver invocation</title>
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<programlisting role="php">
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<![CDATA[
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<?php
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// Connect to an ODBC database using driver invocation
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$dsn = 'mysql:dbname=testdb;host=127.0.0.1';
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$user = 'dbuser';
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$password = 'dbpass';
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try {
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$dbh = new PDO($dsn, $user, $password);
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} catch (PDOException $e) {
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echo 'Connection failed: ' . $e->getMessage();
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}
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?>
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]]>
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</programlisting>
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</example>
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<example><title>Create a PDO instance via URI invocation</title>
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<para>
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The following example assumes that the file
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<filename>/usr/local/dbconnect</filename> exists with file permissions
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that enable PHP to read the file. The file contains the PDO DSN to
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connect to a DB2 database through the PDO_ODBC driver:
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</para>
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<screen>
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<![CDATA[
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odbc:DSN=SAMPLE;UID=john;PWD=mypass
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]]>
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</screen>
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<para>
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The PHP script can then create a database connection by simply
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passing the <literal>uri:</literal> parameter and pointing to
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the file URI:
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</para>
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<programlisting role="php">
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<![CDATA[
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<?php
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// Connect to an ODBC database using driver invocation
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$dsn = 'uri:file:///usr/local/dbconnect';
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$user = '';
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$password = '';
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try {
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$dbh = new PDO($dsn, $user, $password);
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} catch (PDOException $e) {
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echo 'Connection failed: ' . $e->getMessage();
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}
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?>
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]]>
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</programlisting>
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</example>
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<example><title>Create a PDO instance using an alias</title>
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<para>
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The following example assumes that &php.ini; contains the following
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entry to enable a connection to a MySQL database using only the
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alias <literal>mydb</literal>:
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<programlisting role="ini">
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[PDO]
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pdo.dsn.mydb="mysql:dbname=testdb;host=localhost"
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</programlisting>
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</para>
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<programlisting role="php">
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<![CDATA[
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<?php
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// Connect to an ODBC database using an alias
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$dsn = 'mydb';
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$user = '';
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$password = '';
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try {
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$dbh = new PDO($dsn, $user, $password);
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}catch (PDOException $e) {
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echo 'Connection failed: ' . $e->getMessage();
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}
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?>
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]]>
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</programlisting>
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</example>
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</para>
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</refsect1>
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</refentry>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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indent-tabs-mode:nil
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sgml-parent-document:nil
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sgml-default-dtd-file:"../../../../manual.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:nil
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sgml-local-ecat-files:nil
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End:
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vim600: syn=xml fen fdm=syntax fdl=2 si
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vim: et tw=78 syn=sgml
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vi: ts=1 sw=1
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-->
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