blocks|key|1492367|text|rake+db:reset+|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1492368|它通过迁移重新创建您的表。|unstyled|1492369|正如评论中所建议的，一种更快的方法(但你必须添加一个新的rake任务)是：|1492370|namespace+:db+do
++desc+"Truncate+all+tables"
++task+:truncate+=>+:environment+do
++++conn+=+ActiveRecord::Base.connection
++++tables+=+conn.execute("show+tables").map+{+%7Cr%7C+r[0]+}
++++tables.delete+"schema_migrations"
++++tables.each+{+%7Ct%7C+conn.execute("TRUNCATE+#{t}")+}
++end
end|1492371|响应复制自：answer+on+SO。|offset|length|1492372|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/6332189/145248^0|0|0|0|0|6|C|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|X|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|Y|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|A|$B|C]]|$1|K|3|L|5|F|7|10|8|@]|9|@$M|11|N|12|1|13]]|A|$]]|$1|O|3|-4|5|F|7|14|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

<pre><code>rake db:reset 
</code></pre>

It recreates your table from migrations.

As suggested in the comments, a faster way to do it (but you have to add a new rake task) is:

<pre><code>namespace :db do
 desc "Truncate all tables"
 task :truncate =&gt; :environment do
 conn = ActiveRecord::Base.connection
 tables = conn.execute("show tables").map { |r| r[0] }
 tables.delete "schema_migrations"
 tables.each { |t| conn.execute("TRUNCATE #{t}") }
 end
end
</code></pre>

Response copied from: <a href="https://stackoverflow.com/a/6332189/145248">answer on SO</a>.

blocks|key|1492412|text|您可以通过以下方式进行更精细的控制：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1492413|rake+db:drop:all|code-block|syntax|javascript|1492414|然后在不运行迁移的情况下创建数据库，|1492415|rake+db:create:all|1492416|然后运行所有的迁移，|1492417|rake+db:migrate+|1492418|您还可以执行以下操作：|1492419|mysqladmin+drop+databasename|1492420|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|Y|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|10|8|@]|9|@]|A|$]]|$1|Q|3|R|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

You can have finer control with:

<pre><code>rake db:drop:all
</code></pre>

And then create the database without running the migrations,

<pre><code>rake db:create:all
</code></pre>

Then run all your migrations,

<pre><code>rake db:migrate 
</code></pre>

You can also do:

<pre><code>mysqladmin drop databasename
</code></pre>

blocks|key|1277655|text|如果只是想用一组全新的空表重新开始，可以首先确保在db/schema.rb中有一个最新的模式定义：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1277656|rake+db:schema:dump|code-block|syntax|javascript|1277657|然后：|1277658|rake+db:schema:load|1277659|它的效果是删除表，然后重新创建它们，而不需要运行整个迁移过程。|1277660|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

If you simply want to start fresh with a fresh set of empty tables, you can first ensure you have an up-to-date definition of the schema in db/schema.rb:

<pre><code>rake db:schema:dump
</code></pre>

and then:

<pre><code>rake db:schema:load
</code></pre>

which has the effect of dropping tables and then re-creating them, without running through your entire battery of migrations.

blocks|key|1492850|text|在Rails6中，您可以执行rails+db:truncate_all来删除所有数据，而不会删除任何表。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1492851|如果您想在此之后为数据库设定种子，还可以执行rails+db:seed:replant截断所有数据和种子数据库|1492852|entityMap^0|E|L|0|M|L|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|P|8|@]|D|@]|E|$]]]|I|$]]

In Rails 6, you can do <code>rails db:truncate_all</code> to remove all data without dropping any tables.

If you would like to seed your db after that, you could also do <code>rails db:seed:replant</code> to truncate all data and seed database

blocks|key|1492725|text|rails+db:purge|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1492726|最近被添加到rails+4.2.0.alpha的主分支中的ActiveRecord中|1492727|https://github.com/rails/rails/commit/e2f232aba15937a4b9d14bd91e0392c6d55be58d|1492728|entityMap|0|LINK|mutability|MUTABLE|url^0|0|E|0|0|0|26|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|T|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|U|8|@]|D|@$9|V|A|W|1|X]]|E|$]]|$1|J|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|K|$L|$5|M|N|O|E|$P|I]]]]

<code>rails db:purge</code>

has recently been added to ActiveRecord in the master branch of rails 4.2.0.alpha

<a href="https://github.com/rails/rails/commit/e2f232aba15937a4b9d14bd91e0392c6d55be58d" rel="nofollow noreferrer">https://github.com/rails/rails/commit/e2f232aba15937a4b9d14bd91e0392c6d55be58d</a>

blocks|key|1492660|text|Postgres数据库的接受答案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1492661|namespace+:db+do
++desc+"Truncate+all+tables"
++task+:truncate+=>+:environment+do
++++conn+=+ActiveRecord::Base.connection
++++postgres+=+"SELECT+tablename+FROM+pg_catalog.pg_tables+WHERE+schemaname='public'"
++++tables+=+conn.execute(postgres).map+{+%7Cr%7C+r['tablename']+}
++++tables.delete+"schema_migrations"
++++tables.each+{+%7Ct%7C+conn.execute("TRUNCATE+\"#{t}\"")+}
++end
end|code-block|syntax|javascript|1492662|如果存在类似于ActiveRecord::StatementInvalid+(PG::FeatureNotSupported:+ERROR:++cannot+truncate+a+table+referenced+in+a+foreign+key+constraint)+foreign_key错误|offset|length|style|CODE|1492663|然后，CASCADE选项会有所帮助。|1492664|tables.each+{+%7Ct%7C+conn.execute("TRUNCATE+\"#{t}\"+CASCADE")+}|1492665|entityMap|0|LINK|mutability|MUTABLE|url|https://www.postgresql.org/docs/9.1/sql-truncate.html^0|0|0|7|3K|3S|B|0|3|7|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|10|8|@$I|11|J|12|K|L]|$I|13|J|14|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|15|8|@]|9|@$I|16|J|17|1|18]]|A|$]]|$1|O|3|P|5|D|7|19|8|@]|9|@]|A|$E|F]]|$1|Q|3|-4|5|6|7|1A|8|@]|9|@]|A|$]]]|R|$S|$5|T|U|V|A|$W|X]]]]

Accepted answer with Postgres db:

<pre><code>namespace :db do
 desc "Truncate all tables"
 task :truncate =&gt; :environment do
 conn = ActiveRecord::Base.connection
 postgres = "SELECT tablename FROM pg_catalog.pg_tables WHERE schemaname='public'"
 tables = conn.execute(postgres).map { |r| r['tablename'] }
 tables.delete "schema_migrations"
 tables.each { |t| conn.execute("TRUNCATE \"#{t}\"") }
 end
end
</code></pre>

If there are <code>foreign_key</code> error like <code>ActiveRecord::StatementInvalid (PG::FeatureNotSupported: ERROR: cannot truncate a table referenced in a foreign key constraint)</code>

Then, <a href="https://www.postgresql.org/docs/9.1/sql-truncate.html" rel="nofollow noreferrer">CASCADE</a> option would help.

<pre class="lang-rb prettyprint-override"><code>tables.each { |t| conn.execute("TRUNCATE \"#{t}\" CASCADE") }
</code></pre>

blocks|key|1277970|text|如果您希望在应用程序或rails控制台中使用数据时只删除数据而不接触表：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1277971|Rails.application.eager_load!
ActiveRecord::Base.connection.disable_referential_integrity+do
++ApplicationRecord.descendants.each+do+%7Cmodel%7C
++++model.delete_all
++end
end|code-block|syntax|javascript|1277972|使用此代码，您不必费心手动引用模型和/或外键约束(感谢disable_referential_integrity)。|1277973|与ActiveRecord::Base.descendants不同，ApplicationRecord.descendants只返回真正的应用程序模型(不再有ApplicationRecord、schema_migrations和ar_internal_metadata)。|1277974|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

If you want to delete only the data without touching the tables while using it inside your application or rails console :

<pre><code>Rails.application.eager_load!
ActiveRecord::Base.connection.disable_referential_integrity do
 ApplicationRecord.descendants.each do |model|
 model.delete_all
 end
end
</code></pre>

With this code, you don't have to bother with referencing manually your models and/or with foreign key constraints (thanks to disable_referential_integrity). 
ApplicationRecord.descendants returns only true application models unlike ActiveRecord::Base.descendants (no more ApplicationRecord, schema_migrations and ar_internal_metadata).

blocks|key|1277877|text|这也适用于Rails+4|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1277878|(ActiveRecord::Base.connection.tables+-+['schema_migrations']).each+do+%7Ctable%7C
++++table.classify.constantize.destroy_all
end|code-block|syntax|javascript|1277879|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This will work also for Rails 4

<pre><code>(ActiveRecord::Base.connection.tables - ['schema_migrations']).each do |table|
 table.classify.constantize.destroy_all
end
</code></pre>

blocks|key|1277811|text|您可以列出种子文件(seeds.rb)中的所有模型，然后简单地运行|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1277812|rake+db:seed|code-block|syntax|javascript|1277813|然后，种子文件将如下所示：|1277814|Model1.delete_all
Model2.delete_all
Model3.delete_all
Model4.delete_all
Model5.delete_all
Model6.delete_all
Model7.delete_all|1277815|..。|1277816|在这里，rake+db:reset对你的工作来说太难了。这将完全杀死您的数据库，并从头开始重建它，运行所有迁移等。运行seed命令更快。|offset|length|style|CODE|1277817|entityMap^0|0|0|0|0|0|4|D|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|Y|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|Z|8|@$O|10|P|11|Q|R]]|9|@]|A|$]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

You could list all the models in the seed-file (seeds.rb), and simply run

<pre><code>rake db:seed
</code></pre>

The seed file would then look something like this:

<pre><code>Model1.delete_all
Model2.delete_all
Model3.delete_all
Model4.delete_all
Model5.delete_all
Model6.delete_all
Model7.delete_all
</code></pre>

...

<code>rake db:reset</code> is too much for your job here. That will completely kill off your database and rebuild it from scratch, running all migrations etc. To run the seed command is faster.

blocks|key|1277762|text|#+fast+truncation+of+all+tables+that+need+truncations+(select+is+10x+faster+then+truncate)
#+http://grosser.it/2012/07/03/rubyactiverecord-fastest-way-to-truncate-test-database/
def+truncate_all_tables
++connection+=+ActiveRecord::Base.connection
++connection.disable_referential_integrity+do
++++connection.tables.each+do+%7Ctable_name%7C
++++++next+if+connection.select_value("SELECT+count(*)+FROM+#{table_name}")+==+0
++++++connection.execute("TRUNCATE+TABLE+#{table_name}")
++++end
++end
end|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1277763|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code># fast truncation of all tables that need truncations (select is 10x faster then truncate)
# http://grosser.it/2012/07/03/rubyactiverecord-fastest-way-to-truncate-test-database/
def truncate_all_tables
 connection = ActiveRecord::Base.connection
 connection.disable_referential_integrity do
 connection.tables.each do |table_name|
 next if connection.select_value("SELECT count(*) FROM #{table_name}") == 0
 connection.execute("TRUNCATE TABLE #{table_name}")
 end
 end
end
</code></pre>

blocks|key|1277737|text|我知道这是一个老生常谈的问题，但我想这可能会对某些人有所帮助。这是从数据库中清除所有数据的一种非常快速的方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1277738|tables+=+[]
ActiveRecord::Base.connection.execute("show+tables").each+{+%7Cr%7C+tables+<<+r[0]+}
tables+=+tables+-+["schema_migrations"]
tables.each+do+%7Ctable%7C
++ActiveRecord::Base.connection.execute("DELETE+FROM+#{table}+WHERE+1+=+1")
end|code-block|syntax|javascript|1277739|我在after(:all)代码块的某些规范中使用了这种技术。这比任何用于清除、迁移和重置数据库的Rails+rake任务都要快得多，也更高效。|offset|length|style|CODE|1277740|顺便说一句，如果您在数据库端强制执行外键约束，我敢肯定这很可能会失败。|1277741|entityMap^0|0|0|2|B|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

I know this is an old question, but I thought this might be helpful to someone. This is a very fast way of cleaning out all data from a database.

<pre><code>tables = []
ActiveRecord::Base.connection.execute("show tables").each { |r| tables &lt;&lt; r[0] }
tables = tables - ["schema_migrations"]
tables.each do |table|
 ActiveRecord::Base.connection.execute("DELETE FROM #{table} WHERE 1 = 1")
end
</code></pre>

I use this technique in certain specs in an <code>after(:all)</code> block. This is much faster and more efficient than any of the Rails rake tasks for purging, migrating, reseting the database.

BTW: I'm pretty sure this would likely fail if you were enforcing foreign key constraints on the database side.

blocks|key|1277936|text|我的50美分，用于清理数据库并能够再次运行迁移(在您无法删除数据库的情况下，例如AWS+RDS)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1277937|#+get+connection
conn+=+ActiveRecord::Base.connection
#+find+all+tables+needed+to+be+removed
tables+=+conn.execute("SELECT+*+FROM+pg_catalog.pg_tables+WHERE+schemaname='public'+AND+tablename<>'schema_migrations'").to_a.map+{+%7Cr%7C+r['tablename']+}
#+remove+all+tables+except+schema_migrations
tables.each+{+%7Ct%7C+conn.execute("DROP+TABLE+#{t}")+}
#+clean+migrations+table
conn.execute("TRUNCATE+TABLE+schema_migrations")|code-block|syntax|javascript|1277938|现在你可以运行rake+db:migrate让你的数据库处于干净的状态。|offset|length|style|CODE|1277939|entityMap^0|0|0|7|F|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

My 50 cents, for cleaning db and able to run migrations again (in cases when you can't delete database, eg AWS RDS):

<pre><code># get connection
conn = ActiveRecord::Base.connection
# find all tables needed to be removed
tables = conn.execute("SELECT * FROM pg_catalog.pg_tables WHERE schemaname='public' AND tablename&lt;&gt;'schema_migrations'").to_a.map { |r| r['tablename'] }
# remove all tables except schema_migrations
tables.each { |t| conn.execute("DROP TABLE #{t}") }
# clean migrations table
conn.execute("TRUNCATE TABLE schema_migrations")
</code></pre>

And now you can run <code>rake db:migrate</code> to have your db in a clean state.

blocks|key|1492821|text|基于@Vlad+Zloteanu的回答，这里有一个版本可以删除所有表，同时保留用户记录和登录会话以及一些元信息。您可以根据自己的需求随意调整表格列表。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1492822|#+lib/tasks/db/truncate.rake

namespace+:db+do
++desc+'Truncate+all+tables+except+users+state+and+meta'
++task+truncate:+:environment+do
++++conn+=+ActiveRecord::Base.connection
++++tables+=+conn.tables+-+%25w[
++++++sessions
++++++users
++++++roles
++++++users_roles
++++++schema_migrations
++++++ar_internal_metadata
++++]
++++tables.each+{+%7Ct%7C+conn.execute("TRUNCATE+#{t}")+}

++++puts+"Truncated+tables\n================\n#{tables.sort.join("\n")}"
++end
end|code-block|syntax|javascript|1492823|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Building up on @Vlad Zloteanu's answer, here is a version to remove all tables while keeping the user records and login sessions together with some meta information. Feel free to adjust the list of tables to your requirements.

<pre><code># lib/tasks/db/truncate.rake

namespace :db do
 desc 'Truncate all tables except users state and meta'
 task truncate: :environment do
 conn = ActiveRecord::Base.connection
 tables = conn.tables - %w[
 sessions
 users
 roles
 users_roles
 schema_migrations
 ar_internal_metadata
 ]
 tables.each { |t| conn.execute("TRUNCATE #{t}") }

 puts "Truncated tables\n================\n#{tables.sort.join("\n")}"
 end
end
</code></pre>

blocks|key|1492875|text|如果你想删除所有的表并使用默认值重新初始化，你可以使用。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1492876|rails+db:bootstrap|code-block|syntax|javascript|1492877|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If you want to delete all the tables and re-initialize with default values you can use.
<pre><code>rails db:bootstrap
</code></pre>

I can do <code>Post.delete_all</code> to delete all my posts, but what if I want to delete all posts, comments, blogs, etc.? 

How do I iterate over all my models and run the <code>delete_all</code> method?

How to delete all data from all tables in Rails?

数据库

我可以使用Post.delete_all删除所有帖子，但如果我想删除所有帖子、评论、博客等，该怎么办？如何遍历所有模型并运行delete_all方法？

问如何删除Rails中所有表中的所有数据？
EN

回答 14

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问如何删除Rails中所有表中的所有数据？EN

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问如何删除Rails中所有表中的所有数据？
EN