NAME¶
mysqldiff - Identify differences among database objects
SYNOPSIS¶
mysqldiff [options] {db1[:db1] | db1.obj1[:db2.obj2]} ...
DESCRIPTION¶
This utility reads the definitions of objects and compares them using a
diff-like method to determine whether they are the same. The utility displays
the differences for objects that are not the same.
Use the notation db1:db2 to name two databases to compare, or, alternatively
just db1 to compare two databases with the same name. The latter case is a
convenience notation for comparing same-named databases on different servers.
The comparison may be run against two databases of different names on a single
server by specifying only the
--server1 option. The user can also
connect to another server by specifying the
--server2 option. In this
case, db1 is taken from server1 and db2 from server2.
When a database pair is specified, all objects in one database are compared to
the corresponding objects in the other. Any objects not appearing in either
database produce an error.
To compare a specific pair of objects, add an object name to each database name
in
db.obj format. For example, use
db1.obj1:db2.obj2 to compare
two named objects, or db1.obj1 to compare an object with the same name in
databases with the same name. It is not legal to mix a database name with an
object name. For example,
db1.obj1:db2 and
db1:db2.obj2 are
illegal.
The comparison may be run against a single server for comparing two databases of
different names on the same server by specifying only the
--server1
option. Alternatively, you can also connect to another server by specifying
the
--server2 option. In this case, the first object to compare is
taken from server1 and the second from server2.
By default, the utilty generates object differences as a difference report.
However, you can generate a transformation report containing SQL statements
for transforming the objects for conformity instead. Use the 'sql' value for
the
--difftype option to produce a listing that contains the
appropriate ALTER commands to conform the object definitions for the object
pairs specified. If a transformation cannot be formed, the utility reports the
diff of the object along with a warning statement. See important limitations
in the NOTES section.
To specify how to display diff-style output, use one of the following values
with the
--difftype option:
- unified (default)
- Display unified format output.
- context
- Display context format output.
- differ
- Display differ-style format output.
- sql
- Display SQL transformation statement output.
The
--changes-for option controls the direction of the difference (by
specifying the object to be transformed) in either the difference report
(default) or the transformation report (designated with the
--difftype=sql option). Consider the following command:
mysqldiff --server1=root@host1 --server2=root@host2 --difftype=sql \
db1.table1:dbx.table3
The leftmost database (
db1) exists on the server designated by the
--server1 option (
host1). The rightmost database (
dbx)
exists on the server designated by the
--server2 option (
host2).
- •
- --changes-for=server1: Produce output that shows how
to make the definitions of objects on server1 like the definitions
of the corresponding objects on server2.
- •
- --changes-for=server2: Produce output that shows how
to make the definitions of objects on server2 like the definitions
of the corresponding objects on server1.
The default direction is
server1.
For
sql difference format, you can also see the reverse transformation by
specifying the
--show-reverse option.
The utility stops on the first occurrence of missing objects or when an object
does not match. To override this behavior, specify the
--force option
to cause the utility to attempt to compare all objects listed as arguments.
OPTIONS¶
mysqldiff accepts the following command-line options:
- --help
- Display a help message and exit.
- --changes-for=<direction>
- Specify the server to show transformations to match the
other server. For example, to see the transformation for transforming
object definitions on server1 to match the corresponding definitions on
server2, use --changes-for=server1. Permitted values are
server1 and server2. The default is server1.
- --difftype=<difftype>, -d<difftype>
- Specify the difference display format. Permitted format
values are unified, context, differ, and sql.
The default is unified.
- --force
- Do not halt at the first difference found. Process all
objects to find all differences.
- --quiet, -q
- Do not print anything. Return only an exit code of success
or failure.
- --server1=<source>
- Connection information for the first server in <
user>[:<
passwd>]@<host>[:<port>][:<
socket>] format.
- --server2=<source>
- Connection information for the second server in <
user>[:<
passwd>]@<host>[:<port>][:<
socket>] format.
- --show-reverse
- Produce a transformation report containing the SQL
statements to conform the object definitions specified in reverse. For
example, if --changes-for is set to server1, also generate the
transformation for server2. Note: The reverse changes are annotated and
marked as comments.
- --verbose, -v
- Specify how much information to display. Use this option
multiple times to increase the amount of information. For example,
-v = verbose, -vv = more verbose, -vvv = debug.
- --version
- Display version information and exit.
- --width=<number>
- Change the display width of the test report. The default is
75 characters.
NOTES¶
You must provide connection parameters (user, host, password, and so forth) for
an account that has the appropriate privileges to access all objects to be
compared.
The SQL transformation feature has these known limitations:
- •
- When tables with partition differences are encountered, the
utility generates the ALTER TABLE statement for all other changes
but prints a warning and omits the partition differences.
- •
- If the transformation detects table options in the source
table (specified with the --changes-for option) that are not
changed or do not exist in the target table, the utility generates the
ALTER TABLE statement for all other changes but prints a warning
and omits the table option differences.
- •
- Rename for events is not supported. This is because
mysqldiff compares objects by name. In this case, depending on the
direction of the diff, the event is identified as needing to be added or a
DROP EVENT statement is generated.
- •
- Changes in the definer clause for events are not
supported.
- •
- SQL extensions specific to MySQL Cluster are not
supported.
For the
--difftype option, the permitted values are not case sensitive.
In addition, values may be specified as any unambiguous prefix of a valid
value. For example,
--difftype=d specifies the differ type. An error
occurs if a prefix matches more than one valid value.
EXAMPLES¶
To compare the
employees and
emp databases on the local server,
use this command:
$ mysqldiff --server1=root@localhost employees:emp1
# server1 on localhost: ... connected.
WARNING: Objects in server1:employees but not in server2:emp1:
EVENT: e1
Compare failed. One or more differences found.
$ mysqldiff --server1=root@localhost \
employees.t1:emp1.t1 employees.t3:emp1.t3
# server1 on localhost: ... connected.
# Comparing employees.t1 to emp1.t1 [PASS]
# server1 on localhost: ... connected.
# Comparing employees.t3 to emp1.t3 [PASS]
Success. All objects are the same.
$ mysqldiff --server1=root@localhost \
employees.salaries:emp1.salaries --differ
# server1 on localhost: ... connected.
# Comparing employees.salaries to emp1.salaries [FAIL]
# Object definitions are not the same:
CREATE TABLE `salaries` (
`emp_no` int(11) NOT NULL,
`salary` int(11) NOT NULL,
`from_date` date NOT NULL,
`to_date` date NOT NULL,
PRIMARY KEY (`emp_no`,`from_date`),
KEY `emp_no` (`emp_no`)
- ) ENGINE=InnoDB DEFAULT CHARSET=latin1
? ^^^^^
+ ) ENGINE=MyISAM DEFAULT CHARSET=latin1
? ++ ^^^
Compare failed. One or more differences found.
The following examples show how to generate a transformation report. Assume the
following object definitions:
Host1:
CREATE TABLE db1.table1 (num int, misc char(30));
Host2:
CREATE TABLE dbx.table3 (num int, notes char(30), misc char(55));
To generate a set of SQL statements that transform the definition of
db1.table1 to
dbx.table3, use this command:
$ mysqldiff --server1=root@host1 --server2=root@host2 \
--changes-for=server1 --difftype=sql \
db1.table1:dbx.table3
# server1 on host1: ... connected.
# server2 on host2: ... connected.
# Comparing db1.table1 to dbx.table3 [FAIL]
# Transformation statments:
ALTER TABLE db1.table1
ADD COLUMN notes char(30) AFTER a,
CHANGE COLUMN misc misc char(55);
Compare failed. One or more differences found.
To generate a set of SQL statements that transform the definition of
dbx.table3 to
db1.table1, use this command:
$ mysqldiff --server1=root@host1 --server2=root@host2 \
--changes-for=server2 --difftype=sql \
db1.table1:dbx.table3
# server1 on host1: ... connected.
# server2 on host2: ... connected.
# Comparing db1.table1 to dbx.table3 [FAIL]
# Transformation statments:
ALTER TABLE dbx.table3
DROP COLUMN notes,
CHANGE COLUMN misc misc char(30);
Compare failed. One or more differences found.
To generate a set of SQL statements that transform the definitions of
dbx.table3 and
db1.table1 in both directions, use this command:
$ mysqldiff --server1=root@host1 --server2=root@host2 \
--show-reverse --difftype=sql \
db1.table1:dbx.table3
# server1 on host1: ... connected.
# server2 on host2: ... connected.
# Comparing db1.table1 to dbx.table3 [FAIL]
# Transformation statments:
# --destination=server1:
ALTER TABLE db1.table1
ADD COLUMN notes char(30) AFTER a,
CHANGE COLUMN misc misc char(55);
# --destination=server2:
# ALTER TABLE dbx.table3
# DROP COLUMN notes,
# CHANGE COLUMN misc misc char(30);
Compare failed. One or more differences found.
COPYRIGHT¶
Copyright (c) 2011, 2012, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 51 Franklin
St, Fifth Floor, Boston, MA 02110-1301 USA
AUTHOR¶
MySQL Utilities Team
COPYRIGHT¶
2010, Oracle and/or its affiliates. All rights reserved.