query_criteria.po

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"Version properties, identifiers and associations are ignored. By default, "
"null valued properties are excluded."
msgstr "版本属性、标识符和关联被忽略。默认情况下值为null的属性将被排除。"

#. Tag: para
#: query_criteria.xml:150
#, no-c-format
msgid "You can adjust how the <literal>Example</literal> is applied."
msgstr "你可以自行调整<literal>Example</literal>使之更实用。"

#. Tag: programlisting
#: query_criteria.xml:154
#, no-c-format
msgid ""
"<![CDATA[Example example = Example.create(cat)\n"
"    .excludeZeroes()           //exclude zero valued properties\n"
"    .excludeProperty(\"color\")  //exclude the property named \"color\"\n"
"    .ignoreCase()              //perform case insensitive string "
"comparisons\n"
"    .enableLike();             //use like for string comparisons\n"
"List results = session.createCriteria(Cat.class)\n"
"    .add(example)\n"
"    .list();]]>"
msgstr ""

#. Tag: para
#: query_criteria.xml:156
#, no-c-format
msgid "You can even use examples to place criteria upon associated objects."
msgstr "你甚至可以使用examples在关联对象上放置条件。"

#. Tag: programlisting
#: query_criteria.xml:160
#, no-c-format
msgid ""
"<![CDATA[List results = session.createCriteria(Cat.class)\n"
"    .add( Example.create(cat) )\n"
"    .createCriteria(\"mate\")\n"
"        .add( Example.create( cat.getMate() ) )\n"
"    .list();]]>"
msgstr ""

#. Tag: title
#: query_criteria.xml:165
#, no-c-format
msgid "Projections, aggregation and grouping"
msgstr "投影(Projections)、聚合（aggregation）和分组（grouping）"

#. Tag: para
#: query_criteria.xml:166
#, no-c-format
msgid ""
"The class <literal>org.hibernate.criterion.Projections</literal> is a "
"factory for <literal>Projection</literal> instances. We apply a projection "
"to a query by calling <literal>setProjection()</literal>."
msgstr ""
"<literal>org.hibernate.criterion.Projections</literal>是 "
"<literal>Projection</literal> 的实例工厂。我们通过调用 <literal>setProjection"
"()</literal>应用投影到一个查询。"

#. Tag: programlisting
#: query_criteria.xml:172
#, no-c-format
msgid ""
"<![CDATA[List results = session.createCriteria(Cat.class)\n"
"    .setProjection( Projections.rowCount() )\n"
"    .add( Restrictions.eq(\"color\", Color.BLACK) )\n"
"    .list();]]>"
msgstr ""

#. Tag: programlisting
#: query_criteria.xml:174
#, no-c-format
msgid ""
"<![CDATA[List results = session.createCriteria(Cat.class)\n"
"    .setProjection( Projections.projectionList()\n"
"        .add( Projections.rowCount() )\n"
"        .add( Projections.avg(\"weight\") )\n"
"        .add( Projections.max(\"weight\") )\n"
"        .add( Projections.groupProperty(\"color\") )\n"
"    )\n"
"    .list();]]>"
msgstr ""

#. Tag: para
#: query_criteria.xml:176
#, no-c-format
msgid ""
"There is no explicit \"group by\" necessary in a criteria query. Certain "
"projection types are defined to be <emphasis>grouping projections</"
"emphasis>, which also appear in the SQL <literal>group by</literal> clause."
msgstr ""
"在一个条件查询中没有必要显式的使用 \"group by\" 。某些投影类型就是被定义为"
"<emphasis> 分组投影</emphasis>，他们也出现在SQL的<literal>group by</literal>"
"子句中。"

#. Tag: para
#: query_criteria.xml:182
#, no-c-format
msgid ""
"An alias may optionally be assigned to a projection, so that the projected "
"value may be referred to in restrictions or orderings. Here are two "
"different ways to do this:"
msgstr ""
"你可以选择把一个别名指派给一个投影，这样可以使投影值被约束或排序所引用。下面"
"是两种不同的实现方式："

#. Tag: programlisting
#: query_criteria.xml:188
#, no-c-format
msgid ""
"<![CDATA[List results = session.createCriteria(Cat.class)\n"
"    .setProjection( Projections.alias( Projections.groupProperty(\"color\"), "
"\"colr\" ) )\n"
"    .addOrder( Order.asc(\"colr\") )\n"
"    .list();]]>"
msgstr ""

#. Tag: programlisting
#: query_criteria.xml:190
#, no-c-format
msgid ""
"<![CDATA[List results = session.createCriteria(Cat.class)\n"
"    .setProjection( Projections.groupProperty(\"color\").as(\"colr\") )\n"
"    .addOrder( Order.asc(\"colr\") )\n"
"    .list();]]>"
msgstr ""

#. Tag: para
#: query_criteria.xml:192
#, no-c-format
msgid ""
"The <literal>alias()</literal> and <literal>as()</literal> methods simply "
"wrap a projection instance in another, aliased, instance of "
"<literal>Projection</literal>. As a shortcut, you can assign an alias when "
"you add the projection to a projection list:"
msgstr ""
"<literal>alias()</literal>和<literal>as()</literal>方法简便的将一个投影实例包"
"装到另外一个 别名的<literal>Projection</literal>实例中。简而言之，当你添加一"
"个投影到一个投影列表中时 你可以为它指定一个别名："

#. Tag: programlisting
#: query_criteria.xml:199
#, no-c-format
msgid ""
"<![CDATA[List results = session.createCriteria(Cat.class)\n"
"    .setProjection( Projections.projectionList()\n"
"        .add( Projections.rowCount(), \"catCountByColor\" )\n"
"        .add( Projections.avg(\"weight\"), \"avgWeight\" )\n"
"        .add( Projections.max(\"weight\"), \"maxWeight\" )\n"
"        .add( Projections.groupProperty(\"color\"), \"color\" )\n"
"    )\n"
"    .addOrder( Order.desc(\"catCountByColor\") )\n"
"    .addOrder( Order.desc(\"avgWeight\") )\n"
"    .list();]]>"
msgstr ""

#. Tag: programlisting
#: query_criteria.xml:201
#, no-c-format
msgid ""
"<![CDATA[List results = session.createCriteria(Domestic.class, \"cat\")\n"
"    .createAlias(\"kittens\", \"kit\")\n"
"    .setProjection( Projections.projectionList()\n"
"        .add( Projections.property(\"cat.name\"), \"catName\" )\n"
"        .add( Projections.property(\"kit.name\"), \"kitName\" )\n"
"    )\n"
"    .addOrder( Order.asc(\"catName\") )\n"
"    .addOrder( Order.asc(\"kitName\") )\n"
"    .list();]]>"
msgstr ""

#. Tag: para
#: query_criteria.xml:203
#, no-c-format
msgid ""
"You can also use <literal>Property.forName()</literal> to express "
"projections:"
msgstr "你也可以使用<literal>Property.forName()</literal>来表示投影："

#. Tag: programlisting
#: query_criteria.xml:207
#, no-c-format
msgid ""
"<![CDATA[List results = session.createCriteria(Cat.class)\n"
"    .setProjection( Property.forName(\"name\") )\n"
"    .add( Property.forName(\"color\").eq(Color.BLACK) )\n"
"    .list();]]>"
msgstr ""

#. Tag: programlisting
#: query_criteria.xml:209
#, no-c-format
msgid ""
"<![CDATA[List results = session.createCriteria(Cat.class)\n"
"    .setProjection( Projections.projectionList()\n"
"        .add( Projections.rowCount().as(\"catCountByColor\") )\n"
"        .add( Property.forName(\"weight\").avg().as(\"avgWeight\") )\n"
"        .add( Property.forName(\"weight\").max().as(\"maxWeight\") )\n"
"        .add( Property.forName(\"color\").group().as(\"color\" )\n"
"    )\n"
"    .addOrder( Order.desc(\"catCountByColor\") )\n"
"    .addOrder( Order.desc(\"avgWeight\") )\n"
"    .list();]]>"
msgstr ""

#. Tag: title
#: query_criteria.xml:214
#, no-c-format
msgid "Detached queries and subqueries"
msgstr "离线(detached)查询和子查询"

#. Tag: para
#: query_criteria.xml:215
#, no-c-format
msgid ""
"The <literal>DetachedCriteria</literal> class lets you create a query "
"outside the scope of a session, and then later execute it using some "
"arbitrary <literal>Session</literal>."
msgstr ""
"<literal>DetachedCriteria</literal>类使你在一个session范围之外创建一个查询，"
"并且可以使用任意的 <literal>Session</literal>来执行它。"

#. Tag: programlisting
#: query_criteria.xml:220
#, no-c-format
msgid ""
"<![CDATA[DetachedCriteria query = DetachedCriteria.forClass(Cat.class)\n"
"    .add( Property.forName(\"sex\").eq('F') );\n"
"    \n"
"Session session = ....;\n"
"Transaction txn = session.beginTransaction();\n"
"List results = query.getExecutableCriteria(session).setMaxResults(100).list"
"();\n"
"txn.commit();\n"
"session.close();]]>"
msgstr ""

#. Tag: para
#: query_criteria.xml:222
#, no-c-format
msgid ""
"A <literal>DetachedCriteria</literal> may also be used to express a "
"subquery. Criterion instances involving subqueries may be obtained via "
"<literal>Subqueries</literal> or <literal>Property</literal>."
msgstr ""
"<literal>DetachedCriteria</literal>也可以用以表示子查询。条件实例包含子查询可"
"以通过 <literal>Subqueries</literal>或者<literal>Property</literal>获得。"

#. Tag: programlisting
#: query_criteria.xml:228
#, no-c-format
msgid ""
"<![CDATA[DetachedCriteria avgWeight = DetachedCriteria.forClass(Cat.class)\n"
"    .setProjection( Property.forName(\"weight\").avg() );\n"
"session.createCriteria(Cat.class)\n"
"    .add( Property.forName(\"weight\").gt(avgWeight) )\n"
"    .list();]]>"
msgstr ""

#. Tag: programlisting
#: query_criteria.xml:230
#, no-c-format
msgid ""
"<![CDATA[DetachedCriteria weights = DetachedCriteria.forClass(Cat.class)\n"
"    .setProjection( Property.forName(\"weight\") );\n"
"session.createCriteria(Cat.class)\n"
"    .add( Subqueries.geAll(\"weight\", weights) )\n"
"    .list();]]>"
msgstr ""

#. Tag: para
#: query_criteria.xml:232
#, no-c-format
msgid "Even correlated subqueries are possible:"
msgstr "甚至相互关联的子查询也是有可能的："

#. Tag: programlisting
#: query_criteria.xml:236
#, no-c-format
msgid ""
"<![CDATA[DetachedCriteria avgWeightForSex = DetachedCriteria.forClass(Cat."
"class, \"cat2\")\n"
"    .setProjection( Property.forName(\"weight\").avg() )\n"
"    .add( Property.forName(\"cat2.sex\").eqProperty(\"cat.sex\") );\n"
"session.createCriteria(Cat.class, \"cat\")\n"
"    .add( Property.forName(\"weight\").gt(avgWeightForSex) )\n"
"    .list();]]>"
msgstr ""

#. Tag: title
#: query_criteria.xml:245
#, no-c-format
msgid "Queries by natural identifier"
msgstr "根据自然标识查询(Queries by natural identifier)"

#. Tag: para
#: query_criteria.xml:247
#, no-c-format
msgid ""
"For most queries, including criteria queries, the query cache is not very "
"efficient, because query cache invalidation occurs too frequently. However, "
"there is one special kind of query where we can optimize the cache "
"invalidation algorithm: lookups by a constant natural key. In some "
"applications, this kind of query occurs frequently. The criteria API "
"provides special provision for this use case."
msgstr ""
"对大多数查询，包括条件查询而言，因为查询缓存的失效(invalidation)发生得太频"
"繁，查询缓存不是非常高效。然而，有一种特别的查询，可以通过不变的自然键优化缓"
"存的失效算法。在某些应用中，这种类型的查询比较常见。条件查询API对这种用例提供"
"了特别规约。"

#. Tag: para
#: query_criteria.xml:255
#, no-c-format
msgid ""
"First, you should map the natural key of your entity using <literal>&lt;"
"natural-id&gt;</literal>, and enable use of the second-level cache."
msgstr ""
"首先，你应该对你的entity使用<literal>&lt;natural-id&gt;</literal>来映射自然"
"键，然后打开第二级缓存。"

#. Tag: programlisting
#: query_criteria.xml:260
#, no-c-format
msgid ""
"<![CDATA[<class name=\"User\">\n"
"    <cache usage=\"read-write\"/>\n"
"    <id name=\"id\">\n"
"        <generator class=\"increment\"/>\n"
"    </id>\n"
"    <natural-id>\n"
"        <property name=\"name\"/>\n"
"        <property name=\"org\"/>\n"
"    </natural-id>\n"
"    <property name=\"password\"/>\n"
"</class>]]>"
msgstr ""

#. Tag: para
#: query_criteria.xml:262
#, no-c-format
msgid ""
"Note that this functionality is not intended for use with entities with "
"<emphasis>mutable</emphasis> natural keys."
msgstr "注意,此功能对具有<emphasis>mutable</emphasis>自然键的entity并不适用。"

#. Tag: para
#: query_criteria.xml:267
#, no-c-format
msgid "Next, enable the Hibernate query cache."
msgstr "然后，打开Hibernate 查询缓存。"

#. Tag: para
#: query_criteria.xml:271
#, no-c-format
msgid ""
"Now, <literal>Restrictions.naturalId()</literal> allows us to make use of "
"the more efficient cache algorithm."
msgstr ""
"现在，我们可以用<literal>Restrictions.naturalId()</literal>来使用更加高效的缓"
"存算法。"

#. Tag: programlisting
#: query_criteria.xml:276
#, no-c-format
msgid ""
"<![CDATA[session.createCriteria(User.class)\n"
"    .add( Restrictions.naturalId()\n"
"        .set(\"name\", \"gavin\")\n"
"        .set(\"org\", \"hb\") \n"
"    ).setCacheable(true)\n"
"    .uniqueResult();]]>"
msgstr ""