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.\" ========================================================================
.\"
.IX Title "MYSQLDIFF 1p"
.TH MYSQLDIFF 1p "2018-07-20" "perl v5.26.2" "User Contributed Perl Documentation"
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.nh
.SH "NAME"
mysql\-schema\-diff \- compare MySQL database schemas
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\&    mysql\-schema\-diff [B<options>] B<database1> B<database2>
\&
\&    mysql\-schema\-diff \-\-help
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
\&\fImysql-schema-diff\fR is a Perl script front-end to the
\&\s-1CPAN\s0 <http://www.perl.com/CPAN> module
MySQL::Diff <http://search.cpan.org/search?module=MySQL::Diff> which
compares the data structures (i.e. schema / table definitions) of two
MySQL <http://www.mysql.com/> databases, and returns the differences
as a sequence of MySQL commands suitable for piping into \fImysql\fR
which will transform the structure of the first database to be
identical to that of the second (\fIc.f.\fR \fIdiff\fR and \fIpatch\fR).
.PP
Database structures can be compared whether they are files containing
table definitions or existing databases, local or remote.
.PP
\&\fBN.B.\fR The program makes \fIno\fR attempt to compare any of the data
which may be stored in the databases.  It is purely for comparing the
table definitions.  I have no plans to implement data comparison; it
is a complex problem and I have no need of such functionality anyway.
However there is another program
coldiff <http://rossbeyer.net/software/mysql_coldiff/>
which does this, and is based on an older program called
\&\fIdatadiff\fR which seems to have vanished off the 'net.
.PP
For PostgreSQL there are similar tools such as
pgdiff <http://pgdiff.sourceforge.net/> and
apgdiff <http://apgdiff.startnet.biz/>.
.SH "EXAMPLES"
.IX Header "EXAMPLES"
.Vb 2
\&  # compare table definitions in two files
\&  mysql\-schema\-diff db1.mysql db2.mysql
\&
\&  # compare table definitions in a file \*(Aqdb1.mysql\*(Aq with a database \*(Aqdb2\*(Aq
\&  mysql\-schema\-diff db1.mysql db2
\&
\&  # interactively upgrade schema of database \*(Aqdb1\*(Aq to be like the
\&  # schema described in the file \*(Aqdb2.mysql\*(Aq
\&  mysql\-schema\-diff \-A db1 db2.mysql
\&
\&  # compare table definitions in two databases on a remote machine
\&  mysql\-schema\-diff \-\-host=remote.host.com \-\-user=myaccount db1 db2
\&
\&  # compare table definitions in a local database \*(Aqfoo\*(Aq with a
\&  # database \*(Aqbar\*(Aq on a remote machine, when a file foo already
\&  # exists in the current directory
\&  mysql\-schema\-diff \-\-host2=remote.host.com \-\-password=secret db:foo bar
.Ve
.SH "OPTIONS"
.IX Header "OPTIONS"
.ie n .IP """\-?,  \-\-help""" 4
.el .IP "\f(CW\-?,  \-\-help\fR" 4
.IX Item "-?, --help"
show usage
.ie n .IP """\-A,  \-\-apply""" 4
.el .IP "\f(CW\-A,  \-\-apply\fR" 4
.IX Item "-A, --apply"
interactively patch database1 to match database2
.ie n .IP """\-B,  \-\-batch\-apply""" 4
.el .IP "\f(CW\-B,  \-\-batch\-apply\fR" 4
.IX Item "-B, --batch-apply"
non-interactively patch database1 to match database2
.ie n .IP """\-d,  \-\-debug[=N]""" 4
.el .IP "\f(CW\-d,  \-\-debug[=N]\fR" 4
.IX Item "-d, --debug[=N]"
enable debugging [level N, default 1]
.ie n .IP """\-l,  \-\-list\-tables""" 4
.el .IP "\f(CW\-l,  \-\-list\-tables\fR" 4
.IX Item "-l, --list-tables"
output the list off all used tables
.ie n .IP """\-o,  \-\-only\-both""" 4
.el .IP "\f(CW\-o,  \-\-only\-both\fR" 4
.IX Item "-o, --only-both"
only output changes for tables in both databases
.ie n .IP """\-k,  \-\-keep\-old\-tables""" 4
.el .IP "\f(CW\-k,  \-\-keep\-old\-tables\fR" 4
.IX Item "-k, --keep-old-tables"
don't output \s-1DROP TABLE\s0 commands
.ie n .IP """\-c,  \-\-keep\-old\-columns""" 4
.el .IP "\f(CW\-c,  \-\-keep\-old\-columns\fR" 4
.IX Item "-c, --keep-old-columns"
don't output \s-1DROP COLUMN\s0 commands
.ie n .IP """\-n,  \-\-no\-old\-defs""" 4
.el .IP "\f(CW\-n,  \-\-no\-old\-defs\fR" 4
.IX Item "-n, --no-old-defs"
suppress comments describing old definitions
.ie n .IP """\-t,  \-\-table\-re=REGEXP""" 4
.el .IP "\f(CW\-t,  \-\-table\-re=REGEXP\fR" 4
.IX Item "-t, --table-re=REGEXP"
restrict comparisons to tables matching \s-1REGEXP\s0
.ie n .IP """\-i,  \-\-tolerant""" 4
.el .IP "\f(CW\-i,  \-\-tolerant\fR" 4
.IX Item "-i, --tolerant"
ignore \s-1DEFAULT, AUTO_INCREMENT, COLLATE,\s0 and formatting changes
.ie n .IP """\-S,  \-\-single\-transaction""" 4
.el .IP "\f(CW\-S,  \-\-single\-transaction\fR" 4
.IX Item "-S, --single-transaction"
perform \s-1DB\s0 dump in transaction
For more info see: http://dev.mysql.com/doc/refman/en/mysqldump.html#option_mysqldump_single\-transaction
.ie n .IP """\-h,  \-\-host=[hostname]""" 4
.el .IP "\f(CW\-h,  \-\-host=[hostname]\fR" 4
.IX Item "-h, --host=[hostname]"
connect to host
.ie n .IP """\-P,  \-\-port=[port]""" 4
.el .IP "\f(CW\-P,  \-\-port=[port]\fR" 4
.IX Item "-P, --port=[port]"
use this port for connection
.ie n .IP """\-u,  \-\-user=[user]""" 4
.el .IP "\f(CW\-u,  \-\-user=[user]\fR" 4
.IX Item "-u, --user=[user]"
user for login if not current user
.ie n .IP """\-p,  \-\-password[=password]""" 4
.el .IP "\f(CW\-p,  \-\-password[=password]\fR" 4
.IX Item "-p, --password[=password]"
password to use when connecting to server
.ie n .IP """\-s,  \-\-socket=...""" 4
.el .IP "\f(CW\-s,  \-\-socket=...\fR" 4
.IX Item "-s, --socket=..."
socket to use when connecting to server
.SS "For <databaseN> only, where N == 1 or 2"
.IX Subsection "For <databaseN> only, where N == 1 or 2"
.ie n .IP """\-\-hostN=[hostN]""" 4
.el .IP "\f(CW\-\-hostN=[hostN]\fR" 4
.IX Item "--hostN=[hostN]"
connect to host
.ie n .IP """\-\-portN=[portN]""" 4
.el .IP "\f(CW\-\-portN=[portN]\fR" 4
.IX Item "--portN=[portN]"
use this port for connection
.ie n .IP """\-\-userN=[userN]""" 4
.el .IP "\f(CW\-\-userN=[userN]\fR" 4
.IX Item "--userN=[userN]"
user for login if not current user
.ie n .IP """\-\-passwordN[=passwordN]""" 4
.el .IP "\f(CW\-\-passwordN[=passwordN]\fR" 4
.IX Item "--passwordN[=passwordN]"
password to use when connecting to server
.ie n .IP """\-\-socketN=[socketN]""" 4
.el .IP "\f(CW\-\-socketN=[socketN]\fR" 4
.IX Item "--socketN=[socketN]"
socket to use when connecting to server
.SH "INTERNALS"
.IX Header "INTERNALS"
For both of the database structures being compared, the following
happens:
.IP "\(bu" 4
If the argument is a valid filename, the file is used to create a
temporary database which \f(CW\*(C`mysqldump \-d\*(C'\fR is run on to obtain the table
definitions in canonicalised form.  The temporary database is then
dropped.  (The temporary database is named
\&\f(CW\*(C`test_mysqldiff_temp_something\*(C'\fR because default MySQL permissions
allow anyone to create databases beginning with the prefix \f(CW\*(C`test_\*(C'\fR.)
.IP "\(bu" 4
If the argument is a database, \f(CW\*(C`mysqldump \-d\*(C'\fR is run directly on it.
.IP "\(bu" 4
Where authentication is required, the hostname, username, and password
given by the corresponding options are used (type \f(CW\*(C`mysql\-schema\-diff \-\-help\*(C'\fR
for more information).
.IP "\(bu" 4
Each set of table definitions is now parsed into tables, and fields
and index keys within those tables; these are compared, and the
differences outputted in the form of MySQL statements.
.SH "BUGS, DEVELOPMENT, CONTRIBUTING"
.IX Header "BUGS, DEVELOPMENT, CONTRIBUTING"
See <http://adamspiers.org/computing/mysqldiff/>.
.SH "COPYRIGHT AND LICENSE"
.IX Header "COPYRIGHT AND LICENSE"
Copyright (c) 2000\-2016 Adam Spiers. All rights reserved. This
program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
MySQL::Diff, MySQL::Diff::Database, MySQL::Diff::Table, MySQL::Diff::Utils,
mysql, mysqldump, mysqlshow
.SH "AUTHOR"
.IX Header "AUTHOR"
Adam Spiers <mysqldiff@adamspiers.org>