NAME

mysql-copy-rows-adjust-pk - Copy rows from one table to another, adjust PK column if necessary

VERSION

This document describes version 0.022 of mysql-copy-rows-adjust-pk (from Perl distribution App-MysqlUtils), released on 2022-10-19.

SYNOPSIS

mysql-copy-rows-adjust-pk --help (or -h, -?)

mysql-copy-rows-adjust-pk --version (or -v)

mysql-copy-rows-adjust-pk [--adjust=str] [--config-path=path|-c|--no-config|-C] [--config-profile=profile|-P] [--debug|--log-level=level|--quiet|--trace|--verbose] [--dry-run|-n] [--format=name|--json] [--from=str] [--host=str] [--(no)naked-res] [--no-env] [--page-result[=program]|--view-result[=program]] [--password=str] [--pk-column=str] [--port=int] [--to=str] [--username=str] -- <database>

DESCRIPTION

This utility can be used when you have rows in one table that you want to insert to another table, but the PK might clash. When that happens, the value of the other columns are inspected. When all the values of the other columns match, the row is assumed to be a duplicate and skipped. If some values of the other column differ, then the row is assumed to be different and a new value of the PK column is chosen (there are several choices on how to select the new PK).

An example:

% mysql-copy-rows-adjust-pk db1 --from t1 --to t2 --pk-column id --adjust "add 1000"

Suppose these are the rows in table t1:

id    date                 description        user
--    ----                 -----------        ----
 1    2018-12-03 12:01:01  Created user u1    admin1
 2    2018-12-03 12:44:33  Removed user u1    admin1

And here are the rows in table t2:

id    date                 description        user
--    ----                 -----------        ----
 1    2018-12-03 12:01:01  Created user u1    admin1
 2    2018-12-03 13:00:45  Rebooted machine1  admin1
 3    2018-12-03 13:05:00  Created user u2    admin2

You can see that row id=1 in both tables are identical. This will be skipped. On the other hand, row id=2 in t1 is different with row id=2 in t2. This row will be adjusted: id will be changed to 2+1000=1002. So the final rows in table t2 will be (sorted by date):

id    date                 description        user
--    ----                 -----------        ----
 1    2018-12-03 12:01:01  Created user u1    admin1
 1002 2018-12-03 12:44:33  Removed user u1    admin1
 2    2018-12-03 13:00:45  Rebooted machine1  admin1
 3    2018-12-03 13:05:00  Created user u2    admin2

So basically this utility is similar to MySQL's INSERT ... ON DUPLICATE KEY UPDATE, but will avoid inserting identical rows.

If the adjusted PK column clashes with another row in the target table, the row is skipped.

OPTIONS

* marks required options.

Main options

--adjust=s*

How to adjust the value of the PK column.

Currently the choices are:

  • "add N" add N to the original value.

  • "subtract N" subtract N from the original value.

--database=s*

(No description)

Can also be specified as the 1st command-line argument.

--from=s*

Name of source table.

--pk-column=s*

Name of PK column.

--to=s*

Name of target table.

Configuration options

--config-path=s, -c

Set path to configuration file.

Can actually be specified multiple times to instruct application to read from multiple configuration files (and merge them).

--config-profile=s, -P

Set configuration profile to use.

A single configuration file can contain profiles, i.e. alternative sets of values that can be selected. For example:

[profile=dev]
username=foo
pass=beaver

[profile=production]
username=bar
pass=honey

When you specify --config-profile=dev, username will be set to foo and password to beaver. When you specify --config-profile=production, username will be set to bar and password to honey.

--no-config, -C

Do not use any configuration file.

If you specify --no-config, the application will not read any configuration file.

Connection options

--host=s

Default value:

"localhost"
--password=s

Will try to get default from ~/.my.cnf.

--port=s

Default value:

3306
--username=s

Will try to get default from ~/.my.cnf.

Environment options

--no-env

Do not read environment for default options.

If you specify --no-env, the application wil not read any environment variable.

Logging options

--debug

Shortcut for --log-level=debug.

--log-level=s

Set log level.

By default, these log levels are available (in order of increasing level of importance, from least important to most): trace, debug, info, warn/warning, error, fatal. By default, the level is usually set to warn, which means that log statements with level info and less important levels will not be shown. To increase verbosity, choose info, debug, or trace.

For more details on log level and logging, as well as how new logging levels can be defined or existing ones modified, see Log::ger.

--quiet

Shortcut for --log-level=error.

--trace

Shortcut for --log-level=trace.

--verbose

Shortcut for --log-level=info.

Output options

--format=s

Choose output format, e.g. json, text.

Default value:

undef

Output can be displayed in multiple formats, and a suitable default format is chosen depending on the application and/or whether output destination is interactive terminal (i.e. whether output is piped). This option specifically chooses an output format.

--json

Set output format to json.

--naked-res

When outputing as JSON, strip result envelope.

Default value:

0

By default, when outputing as JSON, the full enveloped result is returned, e.g.:

[200,"OK",[1,2,3],{"func.extra"=>4}]

The reason is so you can get the status (1st element), status message (2nd element) as well as result metadata/extra result (4th element) instead of just the result (3rd element). However, sometimes you want just the result, e.g. when you want to pipe the result for more post-processing. In this case you can use --naked-res so you just get:

[1,2,3]
--page-result

Filter output through a pager.

This option will pipe the output to a specified pager program. If pager program is not specified, a suitable default e.g. less is chosen.

--view-result

View output using a viewer.

This option will first save the output to a temporary file, then open a viewer program to view the temporary file. If a viewer program is not chosen, a suitable default, e.g. the browser, is chosen.

Other options

--dry-run, -n

Run in simulation mode (also via DRY_RUN=1).

--help, -h, -?

Display help message and exit.

--version, -v

Display program's version and exit.

COMPLETION

This script has shell tab completion capability with support for several shells.

bash

To activate bash completion for this script, put:

complete -C mysql-copy-rows-adjust-pk mysql-copy-rows-adjust-pk

in your bash startup (e.g. ~/.bashrc). Your next shell session will then recognize tab completion for the command. Or, you can also directly execute the line above in your shell to activate immediately.

It is recommended, however, that you install modules using cpanm-shcompgen which can activate shell completion for scripts immediately.

tcsh

To activate tcsh completion for this script, put:

complete mysql-copy-rows-adjust-pk 'p/*/`mysql-copy-rows-adjust-pk`/'

in your tcsh startup (e.g. ~/.tcshrc). Your next shell session will then recognize tab completion for the command. Or, you can also directly execute the line above in your shell to activate immediately.

It is also recommended to install shcompgen (see above).

other shells

For fish and zsh, install shcompgen as described above.

CONFIGURATION FILE

This script can read configuration files. Configuration files are in the format of IOD, which is basically INI with some extra features.

By default, these names are searched for configuration filenames (can be changed using --config-path): /home/u1/.config/mysqlutils.conf, /home/u1/mysqlutils.conf, or /etc/mysqlutils.conf.

All found files will be read and merged.

To disable searching for configuration files, pass --no-config.

You can put multiple profiles in a single file by using section names like [profile=SOMENAME] or [SOMESECTION profile=SOMENAME]. Those sections will only be read if you specify the matching --config-profile SOMENAME.

You can also put configuration for multiple programs inside a single file, and use filter program=NAME in section names, e.g. [program=NAME ...] or [SOMESECTION program=NAME]. The section will then only be used when the reading program matches.

You can also filter a section by environment variable using the filter env=CONDITION in section names. For example if you only want a section to be read if a certain environment variable is true: [env=SOMEVAR ...] or [SOMESECTION env=SOMEVAR ...]. If you only want a section to be read when the value of an environment variable equals some string: [env=HOSTNAME=blink ...] or [SOMESECTION env=HOSTNAME=blink ...]. If you only want a section to be read when the value of an environment variable does not equal some string: [env=HOSTNAME!=blink ...] or [SOMESECTION env=HOSTNAME!=blink ...]. If you only want a section to be read when the value of an environment variable includes some string: [env=HOSTNAME*=server ...] or [SOMESECTION env=HOSTNAME*=server ...]. If you only want a section to be read when the value of an environment variable does not include some string: [env=HOSTNAME!*=server ...] or [SOMESECTION env=HOSTNAME!*=server ...]. Note that currently due to simplistic parsing, there must not be any whitespace in the value being compared because it marks the beginning of a new section filter or section name.

To load and configure plugins, you can use either the -plugins parameter (e.g. -plugins=DumpArgs or -plugins=DumpArgs@before_validate_args), or use the [plugin=NAME ...] sections, for example:

[plugin=DumpArgs]
-event=before_validate_args
-prio=99

[plugin=Foo]
-event=after_validate_args
arg1=val1
arg2=val2

which is equivalent to setting -plugins=-DumpArgs@before_validate_args@99,-Foo@after_validate_args,arg1,val1,arg2,val2.

List of available configuration parameters:

adjust (see --adjust)
database (see --database)
format (see --format)
from (see --from)
host (see --host)
log_level (see --log-level)
naked_res (see --naked-res)
password (see --password)
pk_column (see --pk-column)
port (see --port)
to (see --to)
username (see --username)

ENVIRONMENT

MYSQL_COPY_ROWS_ADJUST_PK_OPT

String. Specify additional command-line options.

FILES

/home/u1/.config/mysqlutils.conf

/home/u1/mysqlutils.conf

/etc/mysqlutils.conf

HOMEPAGE

Please visit the project's homepage at https://metacpan.org/release/App-MysqlUtils.

SOURCE

Source repository is at https://github.com/perlancar/perl-App-MysqlUtils.

AUTHOR

perlancar <perlancar@cpan.org>

CONTRIBUTING

To contribute, you can send patches by email/via RT, or send pull requests on GitHub.

Most of the time, you don't need to build the distribution yourself. You can simply modify the code, then test via:

% prove -l

If you want to build the distribution (e.g. to try to install it locally on your system), you can install Dist::Zilla, Dist::Zilla::PluginBundle::Author::PERLANCAR, Pod::Weaver::PluginBundle::Author::PERLANCAR, and sometimes one or two other Dist::Zilla- and/or Pod::Weaver plugins. Any additional steps required beyond that are considered a bug and can be reported to me.

COPYRIGHT AND LICENSE

This software is copyright (c) 2022, 2020, 2019, 2018, 2017, 2016 by perlancar <perlancar@cpan.org>.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

BUGS

Please report any bugs or feature requests on the bugtracker website https://rt.cpan.org/Public/Dist/Display.html?Name=App-MysqlUtils

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.