Andy Wardley > Template-Toolkit-2.00 > Template::Plugin::DBI

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Module Version: 1.03   Source   Latest Release: Template-Toolkit-2.14

NAME ^

Template::Plugin::DBI - Template Plugin interface to the DBI.pm module

SYNOPSIS ^

    # use positional arguments...
    [% USE DBI('dbi:driver:database', 'username', 'password') %]

    # ...or named parameters...
    [% USE DBI(data_source = 'dbi:driver:database',
               username    = 'username', 
               password    = 'password') %]

    # ...or call connect() explicitly
    [% USE DBI %]
    [% DBI.connect(dsn, user, pass) %]

    [% FOREACH item = DBI.query( 'SELECT rows FROM table' ) %]
       Here's some row data: [% item.field %]
    [% END %]

    [% query = DBI.prepare('SELECT * FROM user WHERE manager = ?') %]
    [% FOREACH user = query.execute('sam') %]
       ...
    [% FOREACH user = query.execute('abw') %]
       ...

    [% IF DBI.do("DELETE FROM users WHERE uid = 'sam'") %]
       Oh No!  The user was deleted!
    [% END %]

DESCRIPTION ^

This Template Toolkit plugin module provides an interface to the Perl DBI/DBD modules, allowing you to integrate SQL queries into your template documents.

A DBI plugin object can be created as follows:

    [% USE DBI %]

This creates an uninitialised DBI object. You can then open a connection to a database using the connect() method.

    [% DBI.connect('dbi:driver:database', 'username', 'password') %]

The DBI connection can be opened when the plugin is created by passing arguments to the constructor, called from the USE directive.

    [% USE DBI('dbi:driver:database', 'username', 'password') %]

You can also use named parameters to provide the data source connection string, user name and password.

    [% USE DBI(data_source => 'dbi:driver:database',
               username    => 'username',
               password    => 'password')  %]

Lazy Template hackers may prefer to use 'dsn' or 'connect' as a shorthand form of the 'data_source' parameter, and 'user' and 'pass' as shorthand forms of 'username' and 'password', respectively.

    [% USE DBI(connect => 'dbi:driver:database',
               user    => 'username',
               pass    => 'password')  %]

Any additional DBI attributes can be specified as named parameters. The 'PrintError' attribute defaults to 0 unless explicitly set true.

    [% USE DBI(dsn, user, pass, ChopBlanks=1) %]

Methods can then be called on the plugin object using the familiar dotted notation:

    [% FOREACH item = DBI.query( 'SELECT rows FROM table' ) %]
       Here's some row data: [% item.field %]
    [% END %]

See "OBJECT METHODS" below for further details of the methods available.

An alternate variable name can be provided for the plugin as per regular Template Toolkit syntax:

    [% USE mydb = DBI('dbi:driver:database','username','password') %]

    [% FOREACH item = mydb.query( 'SELECT rows FROM table' ) %]
       ...

You can also specify the DBI plugin name in lower case if you prefer:

    [% USE dbi(dsn, user, pass) %]
    [% FOREACH item = dbi.query( 'SELECT rows FROM table' ) %]
       ...

The disconnect() method can be called to explicitly disconnect the current database, but this generally shouldn't be necessary as it is called automatically when the plugin goes out of scope. You can call connect() at any time to open a connection to another database. The previous connection will be closed automatically.

OBJECT METHODS ^

connect($data_source, $username, $password)

Establishes a database connection. This method accepts both positional and named parameter syntax. e.g.

    [% DBI.connect(data_source, username, password) %]
    [% DBI.connect(data_source = 'dbi:driver:database'
                   username    = 'foo' 
                   password    = 'bar' ) %]

The connect method allows you to connect to a data source explicitly. It can also be used to reconnect an exisiting object to a different data source.

query($sql)

This method submits an SQL query to the database and creates an iterator object to return the results. This may be used directly in a FOREACH directive as shown below. Data is automatically fetched a row at a time from the query result set as required for memory efficiency.

    [% FOREACH row = DBI.query('select * from users') %]
       Each [% row.whatever %] can be processed here
    [% END %]

prepare($sql)

Prepare a query for later execution. This returns a compiled query object (of the Template::Plugin::DBI::Query class) on which the execute() method can subsequently be called.

    [% query = DBI.prepare('SELECT * FROM users WHERE id = ?') %]

execute(@args)

Execute a previously prepared query. This method should be called on the query object returned by the prepare() method. Returns an iterator object which can be used directly in a FOREACH directive.

    [% query = DBI.prepare('SELECT * FROM users WHERE manager = ?') %]

    [% FOREACH user = query.execute('sam') %]
       [% user.name %]
    [% END %]

    [% FOREACH user = query.execute('sam') %]
       [% user.name %]
    [% END %]

do($sql)

The do() method executes a sql statement from which no records are returned. It will return true if the statement was successful

    [% IF DBI.do("DELETE FROM users WHERE uid = 'sam'") %]
       The user was successfully deleted.
    [% END %]

quote($value, $type)

Calls the quote() method on the underlying DBI handle to quote the value specified in the appropriate manner for its type.

disconnect()

Disconnects the current database.

PRE-REQUISITES ^

Perl 5.005, Template-Toolkit 2.00, DBI 1.02

SEE ALSO ^

For general information on the Template Toolkit and DBI modules, see Template and DBI.

AUTHORS ^

The DBI plugin was written by Simon A Matthews, <sam@knowledgepool.com>, with contributions from Andy Wardley <abw@kfs.org>.

HISTORY ^

1.01 2000/11/03 abw

Modified connect method to pass all named arguments to DBI. e.g.

    [% USE DBI(dsn, user, pass, ChopBlanks=1) %]
1.02 2000/11/14 abw

Added prev() and next() methods to Template::Plugin::DBI:Iterator to return the previous and next items in the iteration set or undef if not available.

1.03 2000/11/31 sam

Added _connect method to Plugin::DBI for backwards compatability with code from version 1 of Template that subclassed the plugin

Changed the new method on the DBI plugin so that it checks to see if it is being called by a subclassed object.

Fixed the return value in the DBI plugin when connect is called more than once in the lifetime of the plugin.

COPYRIGHT ^

Copyright (C) 1999-2000 Simon Matthews. All Rights Reserved

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

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