名前¶

DBD::mysqlPP - Perlだけで記述したDBI用MySQLドライバ

概要¶

    use DBI;

    $dsn = "dbi:mysqlPP:database=$database;host=$hostname";

    $dbh = DBI->connect($dsn, $user, $password);

    $drh = DBI->install_driver("mysqlPP");

    $sth = $dbh->prepare("SELECT * FROM foo WHERE bla");
    $sth->execute;
    $numRows = $sth->rows;
    $numFields = $sth->{'NUM_OF_FIELDS'};
    $sth->finish;

例¶

  #!/usr/bin/perl

  use strict;
  use DBI;

  # データベースへ接続
  my $dbh = DBI->connect("dbi:mysqlPP:database=test;host=localhost",
                         "joe", "joe's password",
                         {'RaiseError' => 1});

  # テーブル'foo'をドロップ。'foo'が存在しない時は失敗するかもしれない。
  # したがって evalで括る。
  eval { $dbh->do("DROP TABLE foo") };
  print "Dropping foo failed: $@\n" if $@;

  # 新たにテーブル'foo'を作成する。 これは失敗しないはずなので、
  # エラーをキャッチしない。
  $dbh->do("CREATE TABLE foo (id INTEGER, name VARCHAR(20))");

  # 'foo'に任意のデータをインサートする。名前をクオートするために
  # $dbh->quote() を使用する。
  # quoting the name.
  $dbh->do("INSERT INTO foo VALUES (1, " . $dbh->quote("Tim") . ")");

  # 上記と同じ処理だがプレースホルダを使用する。
  $dbh->do("INSERT INTO foo VALUES (?, ?)", undef, 2, "Jochen");

  # テーブルからデータを読み出す。
  my $sth = $dbh->prepare("SELECT id, name FROM foo");
  $sth->execute();
  while (my $ref = $sth->fetchrow_arrayref()) {
    print "Found a row: id = $ref->[0], name = $ref->[1]\n";
  }
  $sth->finish();

  # データベースから切断する。
  $dbh->disconnect();

説明¶

DBD::mysqlPPはPerlだけで実装したMySQLデーベース用のクライアントインタフェイスです。このモジュールはMySQLのサーバとクライアント間のネットワークプロトコルを実装しているので、libmysqlclientなどの他のMySQLクライアントライブラリを必要としません。つまりこれはMySQLが移植されていないOSからMySQLサーバへ接続できることを意味します。萌え〜ッ！

次の宣言でインタフェイスが使用可能になります。

    use DBI;

その後任意の数のMySQLデータベースサーバと接続し、簡単なオブジェクト指向のAPIを通じてそれらのデータベースに任意の数のクエリを送ることが出来ます。データベースハンドルとステートメントハンドルの2種類のオブジェクトが使用できます。次の記述で connectメソッドはデータベースハンドルを返します:

  $dbh = DBI->connect("dbi:mysqlPP:database=$db;host=$host",
                      $user, $password, {RaiseError => 1});

データベースに接続できたなら、次の記述でSQLステートメントを実行することが出来ます:

  my $query = sprintf("INSERT INTO foo VALUES (%d, %s)",
                      $number, $dbh->quote("name"));
  $dbh->do($query);

quoteとdoメソッドの詳細は DBI(3) を参照してください。別の方法は

  $dbh->do("INSERT INTO foo VALUES (?, ?)", undef,
           $number, $name);

この場合quoteメソッドは自動的に実行されます。bind_paramメソッドについて DBI(3) を参照してください。また、データベースハンドルの詳細については "DATABASE HANDLES" を参照してください。

If you want to retrieve results, you need to create a so-called statement handle with:

  $sth = $dbh->prepare("SELECT id, name FROM $table");
  $sth->execute();

This statement handle can be used for multiple things. First of all you can retreive a row of data:

  my $row = $sth->fetchow_arrayref();

If your table has columns ID and NAME, then $row will be array ref with index 0 and 1. See "STATEMENT HANDLES" below for more details on statement handles.

I's more formal approach:

Class Methods¶

connect

    use DBI;

    $dsn = "dbi:mysqlPP:$database";
    $dsn = "dbi:mysqlPP:database=$database;host=$hostname";
    $dsn = "dbi:mysqlPP:database=$database;host=$hostname;port=$port";

    $dbh = DBI->connect($dsn, $user, $password);

A database must always be specified.

host

The hostname, if not specified or specified as '', will default to an MySQL daemon running on the local machine on the default port for the INET socket.

port

Port where MySQL daemon listens to. default is 3306.

MetaData Method¶

tables

    @names = $dbh->tables;

Returns a list of table and view names, possibly including a schema prefix. This list should include all tables that can be used in a "SELECT" statement without further qualification.

Private MetaData Methods¶

ListDBs

    @dbs = $dbh->func('_ListDBs');

Returns a list of all databases managed by the MySQL daemon.

ListTables

WARNING: This method is obsolete due to DBI's $dbh->tables().

    @tables = $dbh->func('_ListTables');

Once connected to the desired database on the desired mysql daemon with the "DBI-"connect()> method, we may extract a list of the tables that have been created within that database.

"ListTables" returns an array containing the names of all the tables present within the selected database. If no tables have been created, an empty list is returned.

    @tables = $dbh->func('_ListTables');
    foreach $table (@tables) {
        print "Table: $table\n";
    }

DATABASE HANDLES¶

The DBD::mysqlPP driver supports the following attributes of database handles (read only):

  $insertid = $dbh->{'mysqlpp_insertid'};
  $insertid = $dbh->{'mysql_insertid'};

STATEMENT HANDLES¶

The statement handles of DBD::mysqlPP support a number of attributes. You access these by using, for example,

  my $numFields = $sth->{'NUM_OF_FIELDS'};

mysqlpp_insertid/mysql_insertid

MySQL has the ability to choose unique key values automatically. If this happened, the new ID will be stored in this attribute. An alternative way for accessing this attribute is via $dbh->{'mysqlpp_insertid'}. (Note we are using the $dbh in this case!)

NUM_OF_FIELDS

Number of fields returned by a SELECT statement. You may use this for checking whether a statement returned a result. A zero value indicates a non-SELECT statement like INSERT, DELETE or UPDATE.

INSTALLATION¶

To install this module type the following:

   perl Makefile.PL
   make
   make test
   make install

SUPPORT OPERATING SYSTEM¶

This module has been tested on these OSes.

• MacOS 9.x

  with MacPerl5.6.1r.

• MacOS X

  with perl5.6.0 build for darwin.

• Windows2000

  with ActivePerl5.6.1 build631.

• FreeBSD 3.4 and 4.x

  with perl5.6.1 build for i386-freebsd.

  with perl5.005_03 build for i386-freebsd.

DEPENDENCIES¶

This module requires these other modules and libraries:

  DBI
  Net::MySQL

Net::MySQL is a Pure Perl client interface for the MySQL database.

Net::MySQL implements network protool between server and client of MySQL, thus you don't need external MySQL client library like libmysqlclient for this module to work. It means this module enables you to connect to MySQL server from some operation systems which MySQL is not ported. How nifty!

DIFFERENCE FROM "DBD::mysql"¶

The function of DBD::mysql which cannot be used by DBD::mysqlPP is described.

Parameter of Cnstructor¶

Cannot be used.

• msql_configfile

• mysql_compression

• mysql_read_default_file/mysql_read_default_group

• mysql_socket

Private MetaData Methods¶

These methods cannot be used for $drh.

• ListDBs

• ListTables

Server Administration¶

All func() method cannot be used.

• func('createdb')

• func('dropdb')

• func('shutdown')

• func('reload')

Database Handles¶

Cannot be used

• $dbh->{info}

Statement Handles¶

A different part.

• The return value of execute('SELECT * from table')

  Although DBD::mysql makes a return value the number of searched records SQL of SELECT is performed, DBD::mysqlPP surely returns 0E0.

Cannot be used.

• 'mysql_use_result' attribute

• 'ChopBlanks' attribute

• 'is_blob' attribute

• 'is_key' attribute

• 'is_num' attribute

• 'is_pri_key' attribute

• 'is_not_null' attribute

• 'length'/'max_length' attribute

• 'NUUABLE' attribute

• 'table' attribute

• 'TYPE' attribute

• 'mysql_type' attribute

• 'mysql_type_name' attributei

SQL Extensions¶

Cannot be used.

• LISTFIELDS

• LISTINDEX

TODO¶

Enables access to much metadata.

SEE ALSO¶

Net::MySQL, DBD::mysql

作者¶

Hiroyuki OYAMA <[email protected]>

COPYRIGHT AND LICENCE¶

Copyright (C) 2002 Hiroyuki OYAMA. Japan. All rights reserved.

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