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DBD::mysql(3pm) User Contributed Perl Documentation DBD::mysql(3pm)
NAME
DBD::mysql - MySQL driver for the Perl5 Database Interface (DBI)
SYNOPSIS
use DBI;
$dsn = "DBI:mysql:database=$database;host=$hostname;port=$port";
$dbh = DBI->connect($dsn, $user, $password);
$drh = DBI->install_driver("mysql");
@databases = DBI->data_sources("mysql");
or
@databases = DBI->data_sources("mysql",
{"host" => $host, "port" => $port});
$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');
EXAMPLE
#!/usr/bin/perl
use strict;
use DBI();
# Connect to the database.
my $dbh = DBI->connect("DBI:mysql:database=test;host=localhost",
"joe", "joe's password",
{'RaiseError' => 1});
# Drop table 'foo'. This may fail, if 'foo' doesn't exist.
# Thus we put an eval around it.
eval { $dbh->do("DROP TABLE foo") };
print "Dropping foo failed: $@\n" if $@;
# Create a new table 'foo'. This must not fail, thus we don't
# catch errors.
$dbh->do("CREATE TABLE foo (id INTEGER, name VARCHAR(20))");
# INSERT some data into 'foo'. We are using $dbh->quote() for
# quoting the name.
$dbh->do("INSERT INTO foo VALUES (1, " . $dbh->quote("Tim") . ")");
# Same thing, but using placeholders
$dbh->do("INSERT INTO foo VALUES (?, ?)", undef, 2, "Jochen");
# Now retrieve data from the table.
my $sth = $dbh->prepare("SELECT * FROM foo");
$sth->execute();
while (my $ref = $sth->fetchrow_hashref()) {
print "Found a row: id = $ref->{'id'}, name = $ref->{'name'}\n";
}
$sth->finish();
# Disconnect from the database.
$dbh->disconnect();
DESCRIPTION
DBD::mysql is the Perl5 Database Interface driver for the MySQL database. In other words:
DBD::mysql is an interface between the Perl programming language and the MySQL programming
API that comes with the MySQL relational database management system. Most functions pro-
vided by this programming API are supported. Some rarely used functions are missing,
mainly because noone ever requested them. :-)
In what follows we first discuss the use of DBD::mysql, because this is what you will need
the most. For installation, see the sections on INSTALLATION, and "WIN32 INSTALLATION"
below. See EXAMPLE for a simple example above.
From perl you activate the interface with the statement
use DBI;
After that you can connect to multiple MySQL database servers and send multiple queries to
any of them via a simple object oriented interface. Two types of objects are available:
database handles and statement handles. Perl returns a database handle to the connect
method like so:
$dbh = DBI->connect("DBI:mysql:database=$db;host=$host",
$user, $password, {RaiseError => 1});
Once you have connected to a database, you can can execute SQL statements with:
my $query = sprintf("INSERT INTO foo VALUES (%d, %s)",
$number, $dbh->quote("name"));
$dbh->do($query);
See DBI(3) for details on the quote and do methods. An alternative approach is
$dbh->do("INSERT INTO foo VALUES (?, ?)", undef,
$number, $name);
in which case the quote method is executed automatically. See also the bind_param method
in DBI(3). See "DATABASE HANDLES" below for more details on database handles.
If you want to retrieve results, you need to create a so-called statement handle with:
$sth = $dbh->prepare("SELECT * 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_hashref();
If your table has columns ID and NAME, then $row will be hash ref with keys ID and NAME.
See "STATEMENT HANDLES" below for more details on statement handles.
But now for a more formal approach:
Class Methods
connect
use DBI;
$dsn = "DBI:mysql:$database";
$dsn = "DBI:mysql:database=$database;host=$hostname";
$dsn = "DBI:mysql:database=$database;host=$hostname;port=$port";
$dbh = DBI->connect($dsn, $user, $password);
A "database" must always be specified.
host
port
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 UNIX socket.
Should the MySQL daemon be running on a non-standard port number, you may explic-
itly state the port number to connect to in the "hostname" argument, by concate-
nating the hostname and port number together separated by a colon ( ":" ) charac-
ter or by using the "port" argument.
mysql_client_found_rows
Enables (TRUE value) or disables (FALSE value) the flag CLIENT_FOUND_ROWS while
connecting to the MySQL server. This has a somewhat funny effect: Without
mysql_client_found_rows, if you perform a query like
UPDATE $table SET id = 1 WHERE id = 1
then the MySQL engine will always return 0, because no rows have changed. With
mysql_client_found_rows however, it will return the number of rows that have an id
1, as some people are expecting. (At least for compatibility to other engines.)
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_connect_timeout
If your DSN contains the option "mysql_connect_timeout=##", the connect request to
the server will timeout if it has not been successful after the given number of
seconds.
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:
[client]
host=localhost
[perl]
host=perlhost
(Note the order of the entries! The example won't work, if you reverse the
[client] and [perl] sections!)
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. Note that if you specify a default group and do
not specify a file, then the default config files will all be read. See the docu-
mentation 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.
mysql_ssl
A true value turns on the CLIENT_SSL flag when connecting to the MySQL database:
mysql_ssl=1
This means that your communication with the server will be encrypted.
If you turn mysql_ssl on, you might also wish to use the following flags:
mysql_ssl_client_key
mysql_ssl_client_cert
mysql_ssl_ca_file
mysql_ssl_ca_path
mysql_ssl_cipher
These are used to specify the respective parameters of a call to mysql_ssl_set, if
mysql_ssl is turned on.
mysql_local_infile
As of MySQL 3.23.49, the LOCAL capability for LOAD DATA may be disabled in the
MySQL client library by default. If your DSN contains the option
"mysql_local_infile=1", LOAD DATA LOCAL will be enabled. (However, this option is
*ineffective* if the server has also been configured to disallow LOCAL.)
Private MetaData Methods
ListDBs
my $drh = DBI->install_driver("mysql");
@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 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");
whenever possible. It is a design problem of this method, that there's no way of sup-
plying a host name or port number to "data_sources", that's the only reason why we
still support "ListDBs". :-(
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('mysql');
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.
DATABASE HANDLES
The DBD::mysql driver supports the following attributes of database handles (read only):
$errno = $dbh->{'mysql_errno'};
$error = $dbh->{'mysql_error};
$info = $dbh->{'mysql_hostinfo'};
$info = $dbh->{'mysql_info'};
$insertid = $dbh->{'mysql_insertid'};
$info = $dbh->{'mysql_protoinfo'};
$info = $dbh->{'mysql_serverinfo'};
$info = $dbh->{'mysql_stat'};
$threadId = $dbh->{'mysql_thread_id'};
These correspond to mysql_errno(), mysql_error(), mysql_get_host_info(), mysql_info(),
mysql_insert_id(), mysql_get_proto_info(), mysql_get_server_info(), mysql_stat() and
mysql_thread_id(), respectively.
$info_hashref = $dhb->{mysql_dbd_stats}
DBD::mysql keeps track of some statistics in the mysql_dbd_stats attribute. The following
stats are being maintained:
auto_reconnects_ok
The number of times that DBD::mysql successfully reconnected to the mysql server.
auto_reconnects_failed
The number of times that DBD::mysql tried to reconnect to mysql but failed.
The DBD::mysql driver also supports the following attribute(s) of database handles
(read/write):
$bool_value = $dbh->{mysql_auto_reconnect};
$dbh->{mysql_auto_reconnect} = $AutoReconnect ? 1 : 0;
mysql_auto_reconnect
This attribute determines whether DBD::mysql will automatically reconnect to mysql if
the connection be lost. This feature defaults to off; however, if either the GATE-
WAY_INTERFACE or MOD_PERL envionment variable is set, DBD::mysql will turn
mysql_auto_reconnect on. Setting mysql_auto_reconnect to on is not advised if 'lock
tables' is used because if DBD::mysql reconnect to mysql all table locks will be lost.
This attribute is ignored when AutoCommit is turned off, and when AutoCommit is turned
off, DBD::mysql will not automatically reconnect to the server.
STATEMENT HANDLES
The statement handles of DBD::mysql 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});
or
my $sth = $dbh->prepare("QUERY");
$sth->{"mysql_use_result"} = 1;
Column dependent attributes, for example NAME, the column names, are returned as a refer-
ence 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", $i ? "," : "", $$names[$i]);
}
print "\n";
while (my $ref = $sth->fetchrow_arrayref) {
for (my $i = 0; $i < $numFields; $i++) {
printf("%s%s", $i ? "," : "", $$ref[$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::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.
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->{'mysql_insertid'}. (Note we are using the $dbh in this case!)
mysql_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.
mysql_is_key
Reference to an array of boolean values; TRUE indicates, that the respective column is
a key. This is valid for MySQL only.
mysql_is_num
Reference to an array of boolean values; TRUE indicates, that the respective column
contains numeric values.
mysql_is_pri_key
Reference to an array of boolean values; TRUE indicates, that the respective column is
a primary key.
mysql_is_auto_increment
Reference to an array of boolean values; TRUE indicates that the respective column is
an AUTO_INCREMENT column. This is only valid for MySQL.
mysql_length
mysql_max_length
A reference to an array of maximum column sizes. The max_length is the maximum physi-
cally 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.
mysql_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::mysql::FIELD_TYPE_INTERVAL is mapped to DBI::SQL_VARCHAR(). If you need the
native column types, use mysql_type. See below.
mysql_type
A reference to an array of MySQL's native column types, for example
DBD::mysql::FIELD_TYPE_SHORT() or DBD::mysql::FIELD_TYPE_STRING(). Use the TYPE
attribute, if you want portable types like DBI::SQL_SMALLINT() or DBI::SQL_VARCHAR().
mysql_type_name
Similar to mysql, but type names and not numbers are returned. Whenever possible, the
ANSI SQL name is preferred.
TRANSACTION SUPPORT
Beginning with DBD::mysql 2.0416, transactions are supported. The transaction support
works as follows:
o By default AutoCommit mode is on, following the DBI specifications.
o If you execute
$dbh-E<gt>{'AutoCommit'} = 0;
or
$dbh-E<gt>{'AutoCommit'} = 1;
then the driver will set the MySQL server variable autocommit to 0 or 1, respectively.
Switching from 0 to 1 will also issue a COMMIT, following the DBI specifications.
o The methods
$dbh-E<gt>rollback();
$dbh-E<gt>commit();
will issue the commands COMMIT and ROLLBACK, respectively. A ROLLBACK will also be
issued if AutoCommit mode is off and the database handles DESTROY method is called.
Again, this is following the DBI specifications.
Given the above, you should note the following:
o You should never change the server variable autocommit manually, unless you are ignor-
ing DBI's transaction support.
o Switching AutoCommit mode from on to off or vice versa may fail. You should always
check for errors, when changing AutoCommit mode. The suggested way of doing so is
using the DBI flag RaiseError. If you don't like RaiseError, you have to use code
like the following:
$dbh->{'AutoCommit'} = 0;
if ($dbh->{'AutoCommit'}) {
# An error occurred!
}
o If you detect an error while changing the AutoCommit mode, you should no longer use
the database handle. In other words, you should disconnect and reconnect again,
because the transaction mode is unpredictable. Alternatively you may verify the trans-
action mode by checking the value of the server variable autocommit. However, such
behaviour isn't portable.
o DBD::mysql has a "reconnect" feature that handles the so-called MySQL "morning bug":
If the server has disconnected, most probably due to a timeout, then by default the
driver will reconnect and attempt to execute the same SQL statement again. However,
this behaviour is disabled when AutoCommit is off: Otherwise the transaction state
would be completely unpredictable after a reconnect.
o The "reconnect" feature of DBD::mysql can be toggled by using the mysql_auto_reconnect
attribute. This behaviour should be turned off in code that uses LOCK TABLE because if
the database server time out and DBD::mysql reconnect, table locks will be lost with-
out any indication of such loss.
SQL EXTENSIONS
Certain metadata functions of 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
mysql_list_fields (C API) for details.
COMPATIBILITY ALERT
The statement attribute TYPE has changed its meaning, as of DBD::mysql 2.0119. 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.
DBD::mysql is a moving target, due to a number of reasons:
- Of course we have to conform the DBI guidelines and developments.
- We have to keep track with the latest MySQL developments.
- And, surprisingly, we have to be as close to ODBC as possible: This is due to the cur-
rent direction of DBI.
- And, last not least, as any tool it has a little bit life of its own.
This means that a lot of things had to and have to be changed. As I am not interested in
maintaining a lot of compatibility kludges, which only increase the drivers code without
being really usefull, I did and will remove some features, methods or attributes.
To ensure a smooth upgrade, the following policy will be applied:
Obsolete features
The first step is to declare something obsolete. This means, that no code is changed,
but the feature appears in the list of obsolete features. See "Obsolete Features"
below.
Deprecated features
If the feature has been obsolete for quite some time, typically in the next major sta-
ble release, warnings will be inserted in the code. You can suppress these warnings by
setting
$DBD::mysql = 1;
In the docs the feature will be moved from the list of obsolete features to the list
of deprecated features. See "Deprecated Features" below.
Removing features
Finally features will be removed silently in the next major stable release. The fea-
ture will be shown in the list of historic features. See "Historic Features" below.
Example: The statement handle attribute
$sth->{'LENGTH'}
was declared obsolete in DBD::mysql 2.00xy. It was considered deprecated in DBD::mysql
2.02xy and removed in 2.04xy.
Obsolete Features
Database handle attributes
The following database handle attributes are declared obsolete in DBD::mysql 2.09.
They will be deprecated in 2.11 and removed in 2.13.
"$dbh->{'errno'}"
Replaced by "$dbh->{'mysql_errno'}"
"$dbh->{'errmsg'}"
Replaced by "$dbh->{'mysql_error'}"
"$dbh->{'hostinfo'}"
Replaced by "$dbh->{'mysql_hostinfo'}"
"$dbh->{'info'}"
Replaced by "$dbh->{'mysql_info'}"
"$dbh->{'protoinfo'}"
Replaced by "$dbh->{'mysql_protoinfo'}"
"$dbh->{'serverinfo'}"
Replaced by "$dbh->{'mysql_serverinfo'}"
"$dbh->{'stats'}"
Replaced by "$dbh->{'mysql_stat'}"
"$dbh->{'thread_id'}"
Replaced by "$dbh->{'mysql_thread_id'}"
Deprecated Features
_ListTables
Replace with the standard DBI method "$dbh->tables()". See also "$dbh->table_info()".
Portable applications will prefer
@tables = map { $_ =~ s/.*\.//; $_ } $dbh-E<gt>tables()
because, depending on the engine, the string "user.table" will be returned, user being
the table owner. The method will be removed in DBD::mysql version 2.11xy.
Historic Features
_CreateDB
_DropDB
The methods
$dbh-E<gt>func($db, '_CreateDB');
$dbh-E<gt>func($db, '_DropDB');
have been used for creating or dropping databases. They have been removed in 1.21_07
in favour of
$drh-E<gt>func("createdb", $dbname, $host, "admin")
$drh-E<gt>func("dropdb", $dbname, $host, "admin")
_ListFields
The method
$sth = $dbh-E<gt>func($table, '_ListFields');
has been used to list a tables columns names, types and other attributes. This method
has been removed in 1.21_07 in favour of
$sth = $dbh-E<gt>prepare("LISTFIELDS $table");
_ListSelectedFields
The method
$sth->func('_ListSelectedFields');
use to return a hash ref of attributes like 'IS_NUM', 'IS_KEY' and so on. These
attributes are now accessible via
$sth-E<gt>{'mysql_is_num'};
$sth-E<gt>{'mysql_is_key'};
and so on. Thus the method has been removed in 1.21_07.
_NumRows
The method
$sth-E<gt>func('_NumRows');
used to be equivalent to
$sth-E<gt>rows();
and has been removed in 1.21_07.
_InsertID
The method
$dbh-E<gt>func('_InsertID');
used to be equivalent with
$dbh-E<gt>{'mysql_insertid'};
Statement handle attributes
affected_rows
Replaced with $sth->{'mysql_affected_rows'} or the result of $sth->execute().
format_default_size
Replaced with $sth->{'PRECISION'}.
format_max_size
Replaced with $sth->{'mysql_max_length'}.
format_type_name
Replaced with $sth->{'TYPE'} (portable) or $sth->{'mysql_type_name'} (MySQL spe-
cific).
format_right_justify
Replaced with $sth->->{'TYPE'} (portable) or $sth->{'mysql_is_num'} (MySQL spe-
cific).
insertid
Replaced with $sth->{'mysql_insertid'}.
IS_BLOB
Replaced with $sth->{'TYPE'} (portable) or $sth->{'mysql_is_blob'} (MySQL spe-
cific).
is_blob
Replaced with $sth->{'TYPE'} (portable) or $sth->{'mysql_is_blob'} (MySQL spe-
cific).
IS_PRI_KEY
Replaced with $sth->{'mysql_is_pri_key'}.
is_pri_key
Replaced with $sth->{'mysql_is_pri_key'}.
IS_NOT_NULL
Replaced with $sth->{'NULLABLE'} (do not forget to invert the boolean values).
is_not_null
Replaced with $sth->{'NULLABLE'} (do not forget to invert the boolean values).
IS_NUM
Replaced with $sth->{'TYPE'} (portable) or $sth->{'mysql_is_num'} (MySQL spe-
cific).
is_num
Replaced with $sth->{'TYPE'} (portable) or $sth->{'mysql_is_num'} (MySQL spe-
cific).
IS_KEY
Replaced with $sth->{'mysql_is_key'}.
is_key
Replaced with $sth->{'mysql_is_key'}.
MAXLENGTH
Replaced with $sth->{'mysql_max_length'}.
maxlength
Replaced with $sth->{'mysql_max_length'}.
LENGTH
Replaced with $sth->{'PRECISION'} (portable) or $sth->{'mysql_length'} (MySQL spe-
cific)
length
Replaced with $sth->{'PRECISION'} (portable) or $sth->{'mysql_length'} (MySQL spe-
cific)
NUMFIELDS
Replaced with $sth->{'NUM_OF_FIELDS'}.
numfields
Replaced with $sth->{'NUM_OF_FIELDS'}.
NUMROWS
Replaced with the result of $sth->execute() or $sth->{'mysql_affected_rows'}.
TABLE
Replaced with $sth->{'mysql_table'}.
table
Replaced with $sth->{'mysql_table'}.
MULTITHREADING
The multithreading capabilities of DBD::mysql 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::mysql is
believed to be completely thread safe, if the C libraries are thread safe and you don't
share handles among threads.
The obvious question is: Are the C libraries thread safe? 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 com-
piled 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.
INSTALLATION
Windows users may skip this section and pass over to "WIN32 INSTALLATION" below. Others,
go on reading.
First of all, you do not need an installed MySQL server for installing DBD::mysql. How-
ever, you need at least the client libraries and possibly the header files, if you are
compiling DBD::mysql from source. In the case of MySQL you can create a client-only ver-
sion by using the configure option --without-server. If you are using precompiled bina-
ries, then it may be possible to use just selected RPM's like MySQL-client and MySQL-devel
or something similar, depending on the distribution.
First you need to install the DBI module. For using dbimon, a simple DBI shell it is rec-
ommended to install Data::ShowTable another Perl module.
I recommend trying automatic installation via the CPAN module. Try
perl -MCPAN -e shell
If you are using the CPAN module for the first time, it will prompt you a lot of ques-
tions. If you finally receive the CPAN prompt, enter
install Bundle::DBD::mysql
If this fails (which may be the case for a number of reasons, for example because you are
behind a firewall or don't have network access), you need to do a manual installation.
First of all you need to fetch the archives from any CPAN mirror, for example
ftp://ftp.funet.fi/pub/languages/perl/CPAN/modules/by-module
The following archives are required (version numbers may have changed, I choose those
which are current as of this writing):
DBI/DBI-1.15.tar.gz
Data/Data-ShowTable-3.3.tar.gz
DBD/DBD-mysql-2.1001.tar.gz
Then enter the following commands:
gzip -cd DBI-1.15.tar.gz | tar xf -
cd DBI-1.15
perl Makefile.PL
make
make test
make install
cd ..
gzip -cd Data-ShowTable-3.3.tar.gz | tar xf -
cd Data-ShowTable-3.3
perl Makefile.PL
make
make install # Don't try make test, the test suite is broken
cd ..
gzip -cd DBD-mysql-2.1001.tar.gz | tar xf -
cd DBD-mysql-2.1001
perl Makefile.PL
make
make test
make install
During "perl Makefile.PL" you will be prompted some questions. Other questions are the
directories with header files and libraries. For example, of your file mysql.h is in
/usr/include/mysql/mysql.h, then enter the header directory /usr, likewise for
/usr/lib/mysql/libmysqlclient.a or /usr/lib/libmysqlclient.so.
WIN32 INSTALLATION
If you are using ActivePerl, you may use ppm to install DBD-mysql. For Perl 5.6, upgrade
to Build 623 or later, then it is sufficient to run
ppm install DBI
ppm install DBD::mysql
If you need an HTTP proxy, you might need to set the environment variable http_proxy, for
example like this:
set http_proxy=http://myproxy.com:8080/
As of this writing, DBD::mysql is missing in the ActivePerl 5.8.0 repository. However,
Randy Kobes has kindly donated an own distribution and the following might succeed:
ppm install http://theoryx5.uwinnipeg.ca/ppms/DBD-mysql.ppd
Otherwise you definitely *need* a C compiler. And it *must* be the same compiler that was
being used for compiling Perl itself. If you don't have a C compiler, the file
README.win32 from the Perl source distribution tells you where to obtain freely dis-
tributable C compilers like egcs or gcc. The Perl sources are available on any CPAN mirror
in the src directory, for example
ftp://ftp.funet.fi/pub/languages/perl/CPAN/src/latest.tar.gz
I recommend using the win32clients package for installing DBD::mysql under Win32, avail-
able for download on www.tcx.se. The following steps have been required for me:
- The current Perl versions (5.6, as of this writing) do have a problem with detecting
the C libraries. I recommend to apply the following patch:
*** c:\Perl\lib\ExtUtils\Liblist.pm.orig Sat Apr 15 20:03:40 2000
--- c:\Perl\lib\ExtUtils\Liblist.pm Sat Apr 15 20:03:45 2000
***************
*** 230,235 ****
--- 230,239 ----
# add "$Config{installarchlib}/CORE" to default search path
push @libpath, "$Config{installarchlib}/CORE";
+ if ($VC and exists($ENV{LIB}) and defined($ENV{LIB})) {
+ push(@libpath, split(/;/, $ENV{LIB}));
+ }
+
foreach (Text::ParseWords::quotewords('\s+', 0, $potential_libs)){
$thislib = $_;
- Extract sources into C:\. This will create a directory C:\mysql with subdirectories
include and lib.
IMPORTANT: Make sure this subdirectory is not shared by other TCX files! In particular
do *not* store the MySQL server in the same directory. If the server is already
installed in C:\mysql, choose a location like C:\tmp, extract the win32clients there.
Note that you can remove this directory entirely once you have installed DBD::mysql.
- Extract the DBD::mysql sources into another directory, for example C:\src\siteperl
- Open a DOS shell and change directory to C:\src\siteperl.
- The next step is only required if you repeat building the modules: Make sure that you
have a clean build tree by running
nmake realclean
If you don't have VC++, replace nmake with your flavour of make. If error messages are
reported in this step, you may safely ignore them.
- Run
perl Makefile.PL
which will prompt you for some settings. The really important ones are:
Which DBMS do you want to use?
enter a 1 here (MySQL only), and
Where is your mysql installed? Please tell me the directory that
contains the subdir include.
where you have to enter the win32clients directory, for example C:\mysql or
C:\tmp\mysql.
- Continued in the usual way:
nmake
nmake install
If you want to create a PPM package for the ActiveState Perl version, then modify the
above steps as follows: Run
perl Makefile.PL NAME=DBD-mysql BINARY_LOCATION=DBD-mysql.tar.gz
nmake ppd
nmake
Once that is done, use tar and gzip (for example those from the CygWin32 distribution) to
create an archive:
mkdir x86
tar cf x86/DBD-mysql.tar blib
gzip x86/DBD-mysql.tar
Put the files x86/DBD-mysql.tar.gz and DBD-mysql.ppd onto some WWW server and install them
by typing
install http://your.server.name/your/directory/DBD-mysql.ppd
in the PPM program.
AUTHORS
The current version of DBD::mysql is almost completely written by Jochen Wiedmann, and is
now being maintained by Rudy Lippan (rlippan AT remotelinux.com). The first version's author
was Alligator Descartes (descarte AT symbolstone.org), who has been aided and abetted by Gary
Shea, Andreas Knig and Tim Bunce amongst others.
The Mysql module was originally written by Andreas Knig <koenig AT kulturbox.de>. The current
version, mainly an emulation layer, is from Jochen Wiedmann.
COPYRIGHT
This module is Copyright (c) 2003 Rudolf Lippan; Large Portions Copyright (c) 1997-2003
Jochen Wiedmann, with code portions Copyright (c)1994-1997 their original authors This
module is released under the same license as Perl itself. See the Perl README for details.
MAILING LIST SUPPORT
This module is maintained and supported on a mailing list,
perl AT lists.com
To subscribe to this list, send a mail to
perl-subscribe AT lists.com
or
perl-digest-subscribe AT lists.com
Mailing list archives are available at
http://www.progressive-comp.com/Lists/?l=msql-mysql-modules
Additionally you might try the dbi-user mailing list for questions about DBI and its mod-
ules 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 fol-
lowing URL:
http://www.symbolstone.org/technology/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!
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