David E. Wheeler > App-Sqitch-0.940 > sqitch

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Name ^

sqitch - Sane database change management

Synopsis ^

  sqitch [<options>] <command> [<command-options>] [<args>]

Description ^

Sqitch is a database change management application. What makes it different from your typical migration-style approaches? A few things:

No opinions

Sqitch is not integrated with any framework, ORM, or platform. Rather, it is a standalone change management system with no opinions about your database engine, application framework, or your development environment.

Native scripting

Changes are implemented as scripts native to your selected database engine. Writing a PostgreSQL application? Write SQL scripts for psql. Writing a MySQL-backed app? Write SQL scripts for mysql.

Dependency resolution

Database changes may declare dependencies on other changes -- even on changes from other Sqitch projects. This ensures proper order of execution, even when you've committed changes to your VCS out-of-order.

No numbering

Change deployment is managed by maintaining a plan file. As such, there is no need to number your changes, although you can if you want. Sqitch doesn't much care how you name your changes.

Iterative Development

Up until you tag and release your application, you can modify your change deployment scripts as often as you like. They're not locked in just because they've been committed to your VCS. This allows you to take an iterative approach to developing your database schema. Or, better, you can do test-driven database development.

Terminology

change

A named unit of change. A change name must be used in the file names of its deploy and a revert scripts. It may also be used in a verify script file name.

tag

A known deployment state, pointing to a single change, typically corresponding to a release. Think of it is a version number or VCS revision. A given point in the plan may have any number of tags.

state

The current state of the database. This is represented by the most recently-deployed change. If the state of the database is the same as the most recent change, then it is considered "up-to-date".

plan

A list of one or more changes and their dependencies that define the order of deployment execution. The plan is stored in a "plan file," usually named sqitch.plan. Sqitch reads the plan file to determine what changes to execute to change the database from one state to another.

add

The act of adding a change to the plan. Sqitch will generate scripts for the change, which you then may modify with the necessary code (typically DDLs) to actually deploy, revert, and verify the change.

deploy

The act of deploying changes to a database. Sqitch reads the plan, checks the current state of the database, and applies all the changes necessary to either bring the database up-to-date or to a requested state (a change name or tag).

revert

The act of reverting database changes to reach an earlier deployment state. Sqitch reads the list of deployed changes from the database and reverts them in the reverse of the order in which they were applied. All changes may be reverted, or changes may be reverted to a requested state (a change name or tag).

committer

User who commits or reverts changes to a database.

planner

User who adds a change to the plan.

Options ^

     --plan-file  FILE    Path to a deployment plan file.
     --engine     ENGINE  Database engine.
     --db-client  PATH    Path to the engine command-line client.
  -d --db-name    NAME    Database name.
  -u --db-user    USER    Database user name.
     --db-host    HOST    Database server host name.
     --db-port    PORT    Database server port number.
     --top-dir    DIR     Path to directory with plan and scripts.
     --deploy-dir DIR     Path to directory with deployment scripts.
     --revert-dir DIR     Path to directory with reversion scripts.
     --verify-dir DIR     Path to directory with verify scripts.
     --extension  EXT     SQL script file name extension.
     --etc-path           Print the path to the etc directory and exit.
     --quiet              Quiet mode with non-error output suppressed.
     --verbose            Increment verbosity.
     --version            Print the version number and exit.
     --help               Show a list of commands and exit.
     --man                Print the introductory documentation and exit.

Options Details ^

--plan-file
  sqitch --plan-file plan.txt

Path to the deployment plan file. Defaults to $top_dir/sqitch.plan. See "Plan File" for a description of its structure.

--engine
  sqitch --engine pg

The database engine to use. Supported engines include:

--db-client
  sqitch --db-client /usr/local/pgsql/bin/psql

Path to the command-line client for the database engine. Defaults to a client in the current path named appropriately for the specified engine.

-d
--db-name
  sqitch --db-name widgets
  sqitch -d bricolage

Name of the database. For some engines, such as PostgreSQL and MySQL, the database must already exist. For others, such as SQLite, the database will be automatically created on first connect.

-u
--db-user
--db-username
  sqitch --db-username root
  sqitch --db-user postgres
  sqitch -u Mom

User name to use when connecting to the database. Does not apply to all engines.

--db-host
  sqitch --db-host db.example.com

Host name to use when connecting to the database. Does not apply to all engines.

--db-port
  sqitch --db-port 7654

Port number to connect to. Does not apply to all engines.

--top-dir
  sqitch --top-dir migrations/

Path to directory containing deploy, revert, and verify SQL scripts. It should contain subdirectories named deploy, revert, and (optionally) verify. These may be overridden by --deploy-dir, --revert-dir, and --verify-dir. Defaults to ./sql.

--deploy-dir
  sqitch --deploy-dir db/up

Path to a directory containing SQL deployment scripts. Overrides the value implied by --top-dir.

--revert-dir
  sqitch --revert-dir db/up

Path to a directory containing SQL reversion scripts. Overrides the value implied by --top-dir.

--verify-dir
  sqitch --verify-dir db/t

Path to a directory containing SQL verify scripts. Overrides the value implied by --top-dir.

--extension
  sqitch --extension ddl

The file name extension on deploy, revert, and verify SQL scripts. Defaults to sql.

--etc-path
  sqitch --etc-path

Print out the path to the Sqitch etc directory and exit. This is the directory where the system-wide configuration file lives, as well as deployment script templates.

--quiet

Suppress normal output messages. Error messages will still be emitted to STDERR. Overrides any value specified by --verbose.

--verbose
  sqitch --verbose --verbose

A value between 0 and 3 specifying how verbose Sqitch should be. Unless --quiet is specified, the default is 1, meaning that Sqitch will output basic status messages as it does its thing. Values of 2 and 3 each cause greater verbosity. Ignored if --quiet is specified.

--help
  sqitch --help

Outputs a brief description all known Sqitch commands and exits.

--man
  sqitch --man

Outputs this documentation and exits.

-V
--version
  sqitch --version

Outputs the program name and version and exits.

Sqitch Commands ^

init

Create the plan file and directories for deploy, revert, and verify scripts if they do not already exist. This command is useful for starting a new Sqitch project.

status

Output information about the current deployment state of a database, including the name of the last deployed change, as well as any tags applied to it. If any changes in the plan have not been deployed, they will be listed separately.

log

Search and Output the complete change history of a database. Provides information about when changes were deployed, reverted, or failed, as well as who planned and committed the changes, and when.

plan

*Not yet implemented.

Search and output the list of changes in the plan.

check

*Not yet implemented.

Sanity check the deployment scripts. Checks include:

  • Make sure all deploy scripts have complementary revert scripts.
add

Add a new change.

tag

List tags or tag the latest change.

rework

Rework an existing change.

deploy

Deploy changes.

revert

Revert changes.

verify

*Not yet implemented.

Verify changes. All SQL scripts in --verify-dir will be run. If any return other than success, sqitch verify will return failure, as well. This will allow individual changes to be verified as successful.

config

Get and set project, user, or system Sqitch options.

bundle

Bundle a Sqitch project for distribution. This command copies the Sqitch configuration, plan, and deploy, revert, and verify scripts to a directory, so that it can be packaged up for distribution, such as in an RPM or tarball.

help

Show help for a specific command or, if no command is specified, show the same documentation as --help.

Configuration ^

Sqitch configuration can be set up on a project, user, or system-wide basis. The format of the configuration file, named sqitch.conf, is the same as for git.

Here's an example of a configuration file that might be useful checked into a VCS for a project that deploys to PostgreSQL and stores its deployment scripts with the extension ddl under the migrations directory. It also wants bundle to be created in the _build/sql directory, and to deploy starting with the "gamma" tag:

  [core]
      engine    = pg
      top_dir   = migrations
      extension = ddl

  [core "pg"]
      db_name   = widgetopolis

  [revert]
      to        = gamma

  [bundle]
      from      = gamma
      tags_only = yes
      dest_dir  = _build/sql

And here's an example of useful configuration in ~/.sqitch/sqitch.conf, to point to system-specific engine information:

  [user]
      name      = Marge N. O’Vera
      email     = marge@example.com

  [core "pg"]
      client    = /usr/local/pgsql/bin/psql
      username  = theory

  [core.mysql]
      client    = /usr/local/mysql/bin/mysql
      username  = root

  [core.sqlite]
      client    = /usr/local/bin/sqlite3

Various commands read from the configuration file and adjust their operation accordingly. See sqitch-config for a list.

See Also ^

The original design for Sqitch was sketched out in a number of blog posts:

Other tools that do database change management include:

Rails migrations

Numbered migrations for Ruby on Rails.

Module::Build::DB

Numbered changes in pure SQL, integrated with Perl's Module::Build build system. Does not support reversion.

DBIx::Migration

Numbered migrations in pure SQL.

Versioning

PostgreSQL-specific dependency-tracking solution by depesz.

Author ^

David E. Wheeler <david@justatheory.com>

License ^

Copyright (c) 2012 iovation Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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