NAME

DBD::mSQL / DBD::mysql - mSQL and mysql drivers for the Perl5 Database Interface (DBI)

SYNOPSIS

use DBI;

$driver = "mSQL"; # or "mSQL1";
$dsn = "DBI:$driver:database=$database;host=$hostname";

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

    or

$driver = "mysql";
$dsn = "DBI:$driver:database=$database;$options";

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


$drh = DBI->install_driver("mysql");
@databases = $drh->func($host, $port, '_ListDBs');
@tables = $dbh->func( '_ListTables' );

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

$rc = $drh->func('createdb', $database, $host, $user, $password, 'admin');
$rc = $drh->func('dropdb', $database, $host, $user, $password, 'admin');
$rc = $drh->func('shutdown', $host, $user, $password, 'admin');
$rc = $drh->func('reload', $host, $user, $password, 'admin');

$rc = $dbh->func('createdb', $database, 'admin');
$rc = $dbh->func('dropdb', $database, 'admin');
$rc = $dbh->func('shutdown', 'admin');
$rc = $dbh->func('reload', 'admin');

DESCRIPTION

<DBD::mysql> and <DBD::mSQL> are the Perl5 Database Interface drivers for the mysql, mSQL 1.x and mSQL 2.x databases. The drivers are part of the Msql-Mysql-modules package.

Class Methods

connect

use DBI;

$driver = "mSQL";  #  or "mSQL1"
$dsn = "DBI:$driver:$database";
$dsn = "DBI:$driver:database=$database;$options";

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

    or

$dsn = "DBI:mysql:$database";
$dsn = "DBI:mysql:database=$database;$options";

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

A database must always be specified.

Possible options are, separated by semicolon:

host

port

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

Should the mysql or mSQL daemon be running on a non-standard port number, you may explicitly state the port number to connect to in the hostname argument, by concatenating the hostname and port number together separated by a colon ( : ) character or by using the port argument. This doesn't work for mSQL 2: You have to create an alternative config file and load it using the msql_configfile attribute, see below.

msql_configfile

By default mSQL 2 loads its port settings and similar things from the file InstDir/msql.conf. This option allows you to specify another attribute, as in

DBI->connect("DBI:mSQL:test;msql_configfile=msql_test.conf");

If the filename is not absolute, mSQL will search in certain other locations, see the documentation of the msqlLoadConfigFile() function in the mSQL manual for details.

mysql_compression

As of MySQL 3.22.3, a new feature is supported: If your DSN contains the option "mysql_compression=1", then the communication between client and server will be compressed.

mysql_read_default_file

mysql_read_default_group

These options can be used to read a config file like /etc/my.cnf or ~/.my.cnf. By default MySQL's C client library doesn't use any config files unlike the client programs (mysql, mysqladmin, ...) that do, but outside of the C client library. Thus you need to explicitly request reading a config file, as in

$dsn = "DBI:mysql:test;mysql_read_default_file=/home/joe/my.cnf";
$dbh = DBI->connect($dsn, $user, $password)

The option mysql_read_default_group can be used to specify the default group in the config file: Usually this is the client group, but see the following example:

[perl]
host=perlhost

[client]
host=localhost

If you read this config file, then you'll be typically connected to localhost. However, by using

$dsn = "DBI:mysql:test;mysql_read_default_group=perl;"
    . "mysql_read_default_file=/home/joe/my.cnf";
$dbh = DBI->connect($dsn, $user, $password);

you'll be connected to perlhost. See the (missing :-) documentation of the C function mysql_options() for details.

mysql_socket

As of MySQL 3.21.15, it is possible to choose the Unix socket that is used for connecting to the server. This is done, for example, with

mysql_socket=/dev/mysql

Usually there's no need for this option, unless you are using another location for the socket than that built into the client.

Private MetaData Methods

ListDBs

$drh = DBI->install_driver("~~");
@dbs = $drh->func("$hostname:$port", "_ListDBs");
@dbs = $drh->func($hostname, $port, "_ListDBs");
@dbs = $dbh->func('_ListDBs');

Returns a list of all databases managed by the mysql daemon or mSQL daemon running on $hostname, port $port. This method is rarely needed for databases running on localhost: You should use the portable method

@dbs = DBI->data_sources("mysql");

    or

@dbs = DBI->data_sources("mSQL");

whenever possible. It is a design problem of this method, that there's no way of supplying a host name or port number to data_sources, that's the only reason why we still support ListDBs. :-(

ListTables

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

Once connected to the desired database on the desired mysql or mSQL mSQL 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";
  }

ListFields

Deprecated, see "COMPATIBILITY ALERT" below. Used to be equivalent to

$sth = $dbh->prepare("LISTFIELDS $table");
$sth->execute;

See "SQL EXTENSIONS" below.

ListSelectedFields

Deprecated, see "COMPATIBILITY ALERT" below.

Server Administration

admin

$rc = $drh->func("createdb", $dbname, [host, user, password,], 'admin');
$rc = $drh->func("dropdb", $dbname, [host, user, password,], 'admin');
$rc = $drh->func("shutdown", [host, user, password,], 'admin');
$rc = $drh->func("reload", [host, user, password,], 'admin');

  or

$rc = $dbh->func("createdb", $dbname, 'admin');
$rc = $dbh->func("dropdb", $dbname, 'admin');
$rc = $dbh->func("shutdown", 'admin');
$rc = $dbh->func("reload", 'admin');

For server administration you need a server connection. For obtaining this connection you have two options: Either use a driver handle (drh) and supply the appropriate arguments (host, defaults localhost, user, defaults to '' and password, defaults to ''). A driver handle can be obtained with

$drh = DBI->install_driver('mSQL');

Otherwise reuse the existing connection of a database handle (dbh).

There's only one function available for administrative purposes, comparable to the m(y)sqladmin programs. The command being execute depends on the first argument:

createdb

Creates the database $dbname. Equivalent to "m(y)sqladmin create $dbname".

dropdb

Drops the database $dbname. Equivalent to "m(y)sqladmin drop $dbname".

It should be noted that database deletion is not prompted for in any way. Nor is it undo-able from DBI.

Once you issue the dropDB() method, the database will be gone!

These method should be used at your own risk.

shutdown

Silently shuts down the database engine. (Without prompting!) Equivalent to "m(y)sqladmin shutdown".

reload

Reloads the servers configuration files and/or tables. This can be particularly important if you modify access privileges or create new users.

_CreateDB

_DropDB

These methods are deprecated, see "COMPATIBILITY ALERT" below.!

$rc = $drh->func( $database, '_CreateDB' );
$rc = $drh->func( $database, '_DropDB' );

  or

$rc = $drh->func( $host, $database, '_CreateDB' );
$rc = $drh->func( $host, $database, '_DropDB' );

These methods are equivalent to the admin method with "createdb" or "dropdb" commands, respectively. In particular note the warnings concerning the missing prompt for dropping a database!

DATABASE HANDLES

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

$infoString = $dbh->{'info'};
$threadId = $dbh->{'thread_id'};

These correspond to mysql_info() and mysql_tread_id(), respectively.

STATEMENT HANDLES

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

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

Note, that most attributes are valid only after a successfull execute. An undef value will returned in that case. The most important exception is the mysql_use_result attribute: This forces the driver to use mysql_use_result rather than mysql_store_result. The former is faster and less memory consuming, but tends to block other processes. (That's why mysql_store_result is the default.)

To set the mysql_use_result attribute, use either of the following:

my $sth = $dbh->prepare("QUERY", { "mysql_use_result" => 1});

my $sth = $dbh->prepare("QUERY");
$sth->{"mysql_use_result"} = 1;

Of course it doesn't make sense to set this attribute before calling the execute method.

Column dependent attributes, for example NAME, the column names, are returned as a reference to an array. The array indices are corresponding to the indices of the arrays returned by fetchrow and similar methods. For example the following code will print a header of table names together with all rows:

  my $sth = $dbh->prepare("SELECT * FROM $table");
  if (!$sth) {
      die "Error:" . $dbh->errstr . "\n";
  }
  if (!$sth->execute) {
      die "Error:" . $sth->errstr . "\n";
  }
  my $names = $sth->{'NAME'};
  my $numFields = $sth->{'NUM_OF_FIELDS'};
  for (my $i = 0;  $i < $numFields;  $i++) {
      printf("%s%s", $$names[$i], $i ? "," : "");
  }
  print "\n";
  while (my $ref = $sth->fetchrow_arrayref) {
      for (my $i = 0;  $i < $numFields;  $i++) {
	  printf("%s%s", $$ref[$i], $i ? "," : "");
      }
      print "\n";
  }

For portable applications you should restrict yourself to attributes with capitalized or mixed case names. Lower case attribute names are private to DBD::mSQL and DBD::mysql. The attribute list includes:

ChopBlanks: this attribute determines whether a fetchrow will chop preceding and trailing blanks off the column values. Chopping blanks does not have impact on the max_length attribute.
insertid: MySQL has the ability to choose unique key values automatically. If this happened, the new ID will be stored in this attribute. This attribute is not valid for DBD::mSQL.
is_blob: Reference to an array of boolean values; TRUE indicates, that the respective column is a blob. This attribute is valid for MySQL only.
is_key: Reference to an array of boolean values; TRUE indicates, that the respective column is a key. This is valid for MySQL only.
is_num: Reference to an array of boolean values; TRUE indicates, that the respective column contains numeric values.
is_pri_key: Reference to an array of boolean values; TRUE indicates, that the respective column is a primary key. This is only valid for MySQL and mSQL 1.0.x: mSQL 2.x uses indices.
is_not_null: A reference to an array of boolean values; FALSE indicates that this column may contain NULL's. You should better use the NULLABLE attribute above which is a DBI standard.
length
max_length: A reference to an array of maximum column sizes. The max_length is the maximum physically present in the result table, length gives the theoretically possible maximum. max_length is valid for MySQL only.
NAME: A reference to an array of column names.
NULLABLE: A reference to an array of boolean values; TRUE indicates that this column may contain NULL's.
NUM_OF_FIELDS: Number of fields returned by a SELECT or LISTFIELDS 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.
table: A reference to an array of table names, useful in a JOIN result.
TYPE: A reference to an array of column types. The engine's native column types are mapped to portable types like DBI::SQL_INTEGER() or DBI::SQL_VARCHAR(), as good as possible. Not all native types have a meaningfull equivalent, for example DBD::mSQL::IDX_TYPE() or DBD::mysql::FIELD_TYPE_INTERVAL are mapped to DBI::SQL_VARCHAR(). If you need the native column types, use mysql_type or msql_type, respectively. See below.
mysql_type: A reference to an array of mSQL's native column types, for example DBD::mSQL::INT_TYPE() or DBD::mSQL::CHAR_TYPE(). Use the TYPE attribute, if you want portable types like DBI::SQL_INTEGER() or DBI::SQL_VARCHAR().

SQL EXTENSIONS

Certain metadata functions of mSQL and mysql that are available on the C API level, haven't been implemented here. Instead they are implemented as "SQL extensions" because they return in fact nothing else but the equivalent of a statement handle. These are:

LISTFIELDS $table: Returns a statement handle that describes the columns of $table. Ses the docs of msqlListFields or mysql_list_fields for details.
LISTINDEX $table $index: mSQL only; returns a statement handle that describes the index $index of table $table. See the docs of msqlListIndex for details.

COMPATIBILITY ALERT

The statement attribute TYPE has changed its meaning, as of Msql-Mysql-modules 1.19_19. Formerly it used to be the an array of native engine's column types, but it is now an array of portable SQL column types. The old attribute is still available as mysql_type or msql_type, respectively.

Certain attributes methods have been declared obsolete or deprecated, partially because there names are agains DBI's naming conventions, partially because they are just superfluous or obsoleted by other methods.

Obsoleted attributes and methods will be explicitly listed below. You cannot expect them to work in future versions, but they have not yet been scheduled for removal and currently they should be usable without any code modifications.

Deprecated attributes and methods will currently issue a warning unless you set the variable $DBD::mSQL::QUIET to a true value. This will be the same for Msql-Mysql-modules 1.19xx and 1.20xx. They will be silently removed in 1.21xx.

Here is a list of obsoleted attributes and/or methods:

_CreateDB

_DropDB

deprecated, use

$drh->func("createdb", $dbname, $host, "admin")
$drh->func("dropdb", $dbname, $host, "admin")

_ListFields

deprecated, use

$sth = $dbh->prepare("LISTFIELDS $table")
$sth->execute;

_ListSelectedFields

deprecated, just use the statement handles for accessing the same attributes.

_NumRows

deprecated, use

$numRows = $sth->rows;

IS_PRI_KEY

IS_NOT_NULL

IS_KEY

IS_BLOB

IS_NUM

LENGTH

MAXLENGTH

NUMROWS

NUMFIELDS

RESULT

TABLE

All these statement handle attributes are obsolete. They can be simply replaced by just downcasing the attribute names. You should expect them to be deprecated as of Msql-Mysql-modules 1.1821. (Whenever that will be.)

MULTITHREADING

The multithreading capabilities of the Msql-Mysql-modules depend completely on the underlying C libraries: The modules are working with handle data only, no global variables are accessed or (to the best of my knowledge) thread unsafe functions are called. Thus DBD::mSQL and DBD::mysql are completely thread safe, if the C libraries thread safe and you don't share handles among threads.

The obvious questions is: Are the C libraries thread safe? In the case of mSQL the answer is definitely "no". The C library has a concept of one single active connection at a time and that is not what threads like.

In the case of MySQL the answer is "mostly" and, in theory, you should be able to get a "yes", if the C library is compiled for being thread safe (By default it isn't.) by passing the option -with-thread-safe-client to configure. See the section on How to make a threadsafe client in the manual.

BUGS

The port part of the first argument to the connect call is implemented in an unsafe way when using mSQL. In fact it is just setting the environment variable MSQL_TCP_PORT during the connect call. If another connect call uses another port and the handles are used simultaneously, they will interfere. I doubt that this will ever change.

Msql-2.0.4 and 2.0.4.1 contain a bug that makes ORDER BY and hence the test script t/40bindparam fail. To verify, if this is the case for you, do a

cd Msql
perl -w -I../blib/lib -I../blib/arch t/40bindparam.t

If something is wrong, the script ought to print a number of id's and names. If the id's aren't in order, it is likely, that your mSQL has a bug. See the INSTALL file for a patch.

AUTHORS

DBD::mSQL has been primarily written by Alligator Descartes (descarte@arcana.co.uk), who has been aided and abetted by Gary Shea, Andreas Koenig and Tim Bunce amongst others. Apologies if your name isn't listed, it probably is in the file called 'Acknowledgments'. As of version 0.80 the maintainer is Andreas König. Version 2.00 is an almost complete rewrite by Jochen Wiedmann.

COPYRIGHT

This module is Copyright (c)1997 Jochen Wiedmann, with code portions Copyright (c)1994-1997 their original authors. This module is released under the 'Artistic' license which you can find in the perl distribution.

This document is Copyright (c)1997 Alligator Descartes. All rights reserved. Permission to distribute this document, in full or in part, via email, Usenet, ftp archives or http is granted providing that no charges are involved, reasonable attempt is made to use the most current version and all credits and copyright notices are retained ( the AUTHOR and COPYRIGHT sections ). Requests for other distribution rights, including incorporation into commercial products, such as books, magazine articles or CD-ROMs should be made to Alligator Descartes <descarte@arcana.co.uk>.

MAILING LIST SUPPORT

This module is maintained and supported on a mailing list,

msql-mysql-modules@tcx.se

To subscribe to this list, send a mail with the words

subscribe msql-mysql-modules

subscribe msql-mysql-modules-digest

in the first line of the body to mdomo@tcx.se. A mailing list archive is in preparation.

Additionally you might try the dbi-user mailing list for questions about DBI and its modules in general. Subscribe via

http://www.fugue.com/dbi

Mailing list archives are at

http://www.rosat.mpe-garching.mpg.de/mailing-lists/PerlDB-Interest/
http://outside.organic.com/mail-archives/dbi-users/
http://www.coe.missouri.edu/~faq/lists/dbi.html

ADDITIONAL DBI INFORMATION

Additional information on the DBI project can be found on the World Wide Web at the following URL:

http://www.arcana.co.uk/technologia/perl/DBI

where documentation, pointers to the mailing lists and mailing list archives and pointers to the most current versions of the modules can be used.

Information on the DBI interface itself can be gained by typing:

perldoc DBI

right now!

1 POD Error

The following errors were encountered while parsing the POD:

Around line 904:: Non-ASCII character seen before =encoding in 'König.'. Assuming CP1252

To install DBD::mSQL, copy and paste the appropriate command in to your terminal.

cpanm

cpanm DBD::mSQL

CPAN shell

perl -MCPAN -e shell
install DBD::mSQL

For more information on module installation, please visit the detailed CPAN module installation guide.

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NAME

SYNOPSIS

DESCRIPTION

Class Methods

Private MetaData Methods

Server Administration

DATABASE HANDLES

STATEMENT HANDLES

SQL EXTENSIONS

COMPATIBILITY ALERT

MULTITHREADING

BUGS

AUTHORS

COPYRIGHT

MAILING LIST SUPPORT

ADDITIONAL DBI INFORMATION

Module Install Instructions