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<title>Class: ActiveRecord::Base</title>
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<td><strong>Class</strong></td>
<td class="class-name-in-header">ActiveRecord::Base</td>
</tr>
<tr class="top-aligned-row">
<td><strong>In:</strong></td>
<td>
<a href="../../files/vendor/rails/activerecord/lib/active_record/base_rb.html">
vendor/rails/activerecord/lib/active_record/base.rb
</a>
<br />
<a href="../../files/vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/connection_specification_rb.html">
vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb
</a>
<br />
<a href="../../files/vendor/rails/activerecord/lib/active_record/connection_adapters/db2_adapter_rb.html">
vendor/rails/activerecord/lib/active_record/connection_adapters/db2_adapter.rb
</a>
<br />
<a href="../../files/vendor/rails/activerecord/lib/active_record/connection_adapters/frontbase_adapter_rb.html">
vendor/rails/activerecord/lib/active_record/connection_adapters/frontbase_adapter.rb
</a>
<br />
<a href="../../files/vendor/rails/activerecord/lib/active_record/connection_adapters/mysql_adapter_rb.html">
vendor/rails/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
</a>
<br />
<a href="../../files/vendor/rails/activerecord/lib/active_record/connection_adapters/openbase_adapter_rb.html">
vendor/rails/activerecord/lib/active_record/connection_adapters/openbase_adapter.rb
</a>
<br />
<a href="../../files/vendor/rails/activerecord/lib/active_record/connection_adapters/oracle_adapter_rb.html">
vendor/rails/activerecord/lib/active_record/connection_adapters/oracle_adapter.rb
</a>
<br />
<a href="../../files/vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter_rb.html">
vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
</a>
<br />
<a href="../../files/vendor/rails/activerecord/lib/active_record/connection_adapters/sqlite_adapter_rb.html">
vendor/rails/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
</a>
<br />
<a href="../../files/vendor/rails/activerecord/lib/active_record/connection_adapters/sqlserver_adapter_rb.html">
vendor/rails/activerecord/lib/active_record/connection_adapters/sqlserver_adapter.rb
</a>
<br />
<a href="../../files/vendor/rails/activerecord/lib/active_record/connection_adapters/sybase_adapter_rb.html">
vendor/rails/activerecord/lib/active_record/connection_adapters/sybase_adapter.rb
</a>
<br />
<a href="../../files/vendor/rails/activerecord/lib/active_record/deprecated_finders_rb.html">
vendor/rails/activerecord/lib/active_record/deprecated_finders.rb
</a>
<br />
<a href="../../files/vendor/rails/activerecord/lib/active_record/query_cache_rb.html">
vendor/rails/activerecord/lib/active_record/query_cache.rb
</a>
<br />
</td>
</tr>
<tr class="top-aligned-row">
<td><strong>Parent:</strong></td>
<td>
Object
</td>
</tr>
</table>
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<div id="contextContent">
<div id="description">
<p>
Active Record objects don‘t specify their <a
href="Base.html#M001069">attributes</a> directly, but rather infer them
from the table definition with which they‘re linked. Adding,
removing, and changing <a href="Base.html#M001069">attributes</a> and their
type is done directly in the database. Any change is instantly reflected in
the Active Record objects. The mapping that binds a given Active Record
class to a certain database table will happen automatically in most common
cases, but can be overwritten for the uncommon ones.
</p>
<p>
See the mapping rules in <a href="Base.html#M001022">table_name</a> and the
full example in <a href="../../files/README.html">files/README.html</a> for
more insight.
</p>
<h2>Creation</h2>
<p>
Active Records accept constructor parameters either in a <a
href="Base.html#M001077">hash</a> or as a block. The <a
href="Base.html#M001077">hash</a> method is especially useful when
you‘re receiving the data from somewhere else, like a HTTP request.
It works like this:
</p>
<pre>
user = User.new(:name => "David", :occupation => "Code Artist")
user.name # => "David"
</pre>
<p>
You can also use block initialization:
</p>
<pre>
user = User.new do |u|
u.name = "David"
u.occupation = "Code Artist"
end
</pre>
<p>
And of course you can just <a href="Base.html#M001008">create</a> a bare
object and specify the <a href="Base.html#M001069">attributes</a> after the
fact:
</p>
<pre>
user = User.new
user.name = "David"
user.occupation = "Code Artist"
</pre>
<h2>Conditions</h2>
<p>
Conditions can either be specified as a string, array, or <a
href="Base.html#M001077">hash</a> representing the WHERE-part of an SQL
statement. The array form is to be used when the condition input is tainted
and requires sanitization. The string form can be used for statements that
don‘t involve tainted data. The <a href="Base.html#M001077">hash</a>
form works much like the array form, except only equality and range is
possible. Examples:
</p>
<pre>
class User < ActiveRecord::Base
def self.authenticate_unsafely(user_name, password)
find(:first, :conditions => "user_name = '#{user_name}' AND password = '#{password}'")
end
def self.authenticate_safely(user_name, password)
find(:first, :conditions => [ "user_name = ? AND password = ?", user_name, password ])
end
def self.authenticate_safely_simply(user_name, password)
find(:first, :conditi
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rdoc-style.css 4KB
Base.html 199KB CHANGELOG.html 180KB CHANGELOG.html 172KB fr_method_index.html 148KB Selector.html 101KB Base.html 91KB ClassMethods.html 83KB UTF8Handler.html 75KB SQLServerAdapter.html 69KB ClassMethods.html 66KB SelectorAssertions.html 62KB FrontBaseAdapter.html 60KB DateHelper.html 60KB PrototypeHelper.html 56KB AbstractRequest.html 55KB ClassMethods.html 51KB TextHelper.html 51KB Calculations.html 49KB UrlHelper.html 49KB FormOptionsHelper.html 45KB fr_file_index.html 45KB PostgreSQLAdapter.html 43KB CHANGELOG.html 42KB CHANGELOG.html 42KB DB2Adapter.html 38KB SchemaStatements.html 38KB TimeZone.html 37KB Column.html 37KB GeneratorMethods.html 37KB Session.html 35KB Errors.html 35KB FormTagHelper.html 35KB TestProcess.html 34KB Fixtures.html 34KB FormHelper.html 32KB Inflector.html 32KB JavaScriptMacrosHelper.html 31KB DatabaseStatements.html 31KB AssetTagHelper.html 31KB XmlSimple.html 30KB ResponseAssertions.html 29KB Callbacks.html 27KB Breakpoint.html 26KB NumberHelper.html 26KB AbstractAdapter.html 25KB JavaScriptHelper.html 25KB OracleAdapter.html 25KB Migration.html 24KB ClassMethods.html 24KB Base.html 24KB ActiveRecordHelper.html 23KB Inflections.html 23KB Routing.html 23KB InstanceMethods.html 23KB Chars.html 22KB InstanceMethods.html 22KB Type.html 22KB XmlMarkup.html 21KB Paginator.html 21KB Page.html 21KB HashWithIndifferentAccess.html 21KB Fragments.html 21KB README.html 19KB fr_class_index.html 19KB Time.html 19KB Method.html 18KB MysqlAdapter.html 18KB Conversions.html 18KB Validations.html 17KB OpenBaseAdapter.html 17KB RoutingAssertions.html 17KB FirebirdAdapter.html 16KB README.html 16KB TableDefinition.html 16KB CHANGELOG.html 16KB Pagination.html 16KB SybaseAdapterContext.html 15KB Quoting.html 15KB CompiledTemplates.html 15KB Resources.html 15KB CHANGELOG.html 15KB OCI8AutoRecover.html 15KB Streaming.html 15KB Conversions.html 15KB ClassMethods.html 15KB ScriptaculousHelper.html 14KB Rescue.html 14KB Inflections.html 14KB Base.html 14KB Observer.html 14KB PaginationHelper.html 14KB README.html 14KB Bytes.html 13KB ClassMethods.html 13KB ClassMethods.html 13KB MacroReflection.html 13KB README.html 13KB IntegrationTest.html 13KB ClassMethods.html 13KB共 441 条
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