batch.po

hibernate-distribution-3.3.1.GA-dist.zip源码

#. Tag: para
#: batch.xml:146
#, no-c-format
msgid ""
"The pseudo-syntax for <literal>UPDATE</literal> and <literal>DELETE</"
"literal> statements is: <literal>( UPDATE | DELETE ) FROM? EntityName (WHERE "
"where_conditions)?</literal>. Some points to note:"
msgstr ""
"<literal>UPDATE</literal> 和 <literal>DELETE</literal>语句的语法为： "
"<literal>( UPDATE | DELETE ) FROM? EntityName (WHERE where_conditions)?</"
"literal> 有几点说明："

#. Tag: para
#: batch.xml:154
#, no-c-format
msgid "In the from-clause, the FROM keyword is optional"
msgstr "在FROM子句（from-clause）中，FROM关键字是可选的"

#. Tag: para
#: batch.xml:159
#, no-c-format
msgid ""
"There can only be a single entity named in the from-clause; it can "
"optionally be aliased. If the entity name is aliased, then any property "
"references must be qualified using that alias; if the entity name is not "
"aliased, then it is illegal for any property references to be qualified."
msgstr ""
"在FROM子句（from-clause）中只能有一个实体名，它可以是别名。如果实体名是别名，"
"那么任何被引用的属性都必须加上此别名的前缀；如果不是别名，那么任何有前缀的属"
"性引用都是非法的。"

#. Tag: para
#: batch.xml:167
#, fuzzy, no-c-format
msgid ""
"No <link linkend=\"queryhql-joins-forms\">joins</link> (either implicit or "
"explicit) can be specified in a bulk HQL query. Sub-queries may be used in "
"the where-clause; the subqueries, themselves, may contain joins."
msgstr ""
"不能在大批量HQL语句中使用<xref linkend=\"queryhql-joins-forms\">连接(join)</"
"xref>（显式或者隐式的都不行）。不过在WHERE子句中可以使用子查询。可以在where子"
"句中使用子查询，子查询本身可以包含join。"

#. Tag: para
#: batch.xml:174
#, no-c-format
msgid "The where-clause is also optional."
msgstr "整个WHERE子句是可选的。"

#. Tag: para
#: batch.xml:180
#, no-c-format
msgid ""
"As an example, to execute an HQL <literal>UPDATE</literal>, use the "
"<literal>Query.executeUpdate()</literal> method (the method is named for "
"those familiar with JDBC's <literal>PreparedStatement.executeUpdate()</"
"literal>):"
msgstr ""
"举个例子，使用<literal>Query.executeUpdate()</literal>方法执行一个HQL "
"<literal>UPDATE</literal>语句(： (方法命名是来源于JDBC's "
"<literal>PreparedStatement.executeUpdate()</literal>):"

#. Tag: programlisting
#: batch.xml:186
#, no-c-format
msgid ""
"<![CDATA[Session session = sessionFactory.openSession();\n"
"Transaction tx = session.beginTransaction();\n"
"\n"
"String hqlUpdate = \"update Customer c set c.name = :newName where c.name = :"
"oldName\";\n"
"// or String hqlUpdate = \"update Customer set name = :newName where name = :"
"oldName\";\n"
"int updatedEntities = s.createQuery( hqlUpdate )\n"
"        .setString( \"newName\", newName )\n"
"        .setString( \"oldName\", oldName )\n"
"        .executeUpdate();\n"
"tx.commit();\n"
"session.close();]]>"
msgstr ""

#. Tag: para
#: batch.xml:188
#, fuzzy, no-c-format
msgid ""
"HQL <literal>UPDATE</literal> statements, by default do not effect the <link "
"linkend=\"mapping-declaration-version\">version</link> or the <link linkend="
"\"mapping-declaration-timestamp\">timestamp</link> property values for the "
"affected entities; this is in keeping with the EJB3 specification. However, "
"you can force Hibernate to properly reset the <literal>version</literal> or "
"<literal>timestamp</literal> property values through the use of a "
"<literal>versioned update</literal>. This is achieved by adding the "
"<literal>VERSIONED</literal> keyword after the <literal>UPDATE</literal> "
"keyword."
msgstr ""
"HQL <literal>UPDATE</literal>语句，默认不会影响更新实体的<xref linkend="
"\"mapping-declaration-version\">version</xref>或者<xref linkend=\"mapping-"
"declaration-timestamp\">timestamp</xref>属性值。这和EJB3规范是一致的。但是，"
"通过使用<literal>versioned update</literal>，你可以强制Hibernate正确的重置"
"<literal>version</literal>或者<literal>timestamp</literal>属性值。这通过在"
"<literal>UPDATE</literal>关键字后面增加<literal>VERSIONED</literal>关键字来实"
"现的。"

#. Tag: programlisting
#: batch.xml:198
#, no-c-format
msgid ""
"<![CDATA[Session session = sessionFactory.openSession();\n"
"Transaction tx = session.beginTransaction();\n"
"String hqlVersionedUpdate = \"update versioned Customer set name = :newName "
"where name = :oldName\";\n"
"int updatedEntities = s.createQuery( hqlUpdate )\n"
"        .setString( \"newName\", newName )\n"
"        .setString( \"oldName\", oldName )\n"
"        .executeUpdate();\n"
"tx.commit();\n"
"session.close();]]>"
msgstr ""

#. Tag: para
#: batch.xml:200
#, no-c-format
msgid ""
"Note that custom version types (<literal>org.hibernate.usertype."
"UserVersionType</literal>) are not allowed in conjunction with a "
"<literal>update versioned</literal> statement."
msgstr ""
"注意，自定义的版本类型(<literal>org.hibernate.usertype.UserVersionType</"
"literal>)不允许和<literal>update versioned</literal>语句联用。"

#. Tag: para
#: batch.xml:205
#, no-c-format
msgid ""
"To execute an HQL <literal>DELETE</literal>, use the same <literal>Query."
"executeUpdate()</literal> method:"
msgstr ""
"执行一个HQL <literal>DELETE</literal>，同样使用 <literal>Query.executeUpdate"
"()</literal> 方法:"

#. Tag: programlisting
#: batch.xml:210
#, no-c-format
msgid ""
"<![CDATA[Session session = sessionFactory.openSession();\n"
"Transaction tx = session.beginTransaction();\n"
"\n"
"String hqlDelete = \"delete Customer c where c.name = :oldName\";\n"
"// or String hqlDelete = \"delete Customer where name = :oldName\";\n"
"int deletedEntities = s.createQuery( hqlDelete )\n"
"        .setString( \"oldName\", oldName )\n"
"        .executeUpdate();\n"
"tx.commit();\n"
"session.close();]]>"
msgstr ""

#. Tag: para
#: batch.xml:212
#, no-c-format
msgid ""
"The <literal>int</literal> value returned by the <literal>Query.executeUpdate"
"()</literal> method indicate the number of entities effected by the "
"operation. Consider this may or may not correlate to the number of rows "
"effected in the database. An HQL bulk operation might result in multiple "
"actual SQL statements being executed, for joined-subclass, for example. The "
"returned number indicates the number of actual entities affected by the "
"statement. Going back to the example of joined-subclass, a delete against "
"one of the subclasses may actually result in deletes against not just the "
"table to which that subclass is mapped, but also the \"root\" table and "
"potentially joined-subclass tables further down the inheritence hierarchy."
msgstr ""
"由<literal>Query.executeUpdate()</literal>方法返回的<literal>整型</literal>值"
"表明了受此操作影响的记录数量。 注意这个数值可能与数据库中被（最后一条SQL语"
"句）影响了的“行”数有关，也可能没有。一个大批量HQL操作可能导致多条实际的SQL语"
"句被执行， 举个例子，对joined-subclass映射方式的类进行的此类操作。这个返回值"
"代表了实际被语句影响了的记录数量。在那个joined-subclass的例子中， 对一个子类"
"的删除实际上可能不仅仅会删除子类映射到的表而且会影响“根”表，还有可能影响与之"
"有继承关系的joined-subclass映射方式的子类的表。"

#. Tag: para
#: batch.xml:223
#, no-c-format
msgid ""
"The pseudo-syntax for <literal>INSERT</literal> statements is: "
"<literal>INSERT INTO EntityName properties_list select_statement</literal>. "
"Some points to note:"
msgstr ""
"<literal>INSERT</literal>语句的伪码是: <literal>INSERT INTO EntityName "
"properties_list select_statement</literal>. 要注意的是:"

#. Tag: para
#: batch.xml:231
#, no-c-format
msgid ""
"Only the INSERT INTO ... SELECT ... form is supported; not the INSERT "
"INTO ... VALUES ... form."
msgstr ""
"只支持INSERT INTO ... SELECT ...形式,不支持INSERT INTO ... VALUES ...形式."

#. Tag: para
#: batch.xml:234
#, no-c-format
msgid ""
"The properties_list is analogous to the <literal>column speficiation</"
"literal> in the SQL <literal>INSERT</literal> statement. For entities "
"involved in mapped inheritence, only properties directly defined on that "
"given class-level can be used in the properties_list. Superclass properties "
"are not allowed; and subclass properties do not make sense. In other words, "
"<literal>INSERT</literal> statements are inherently non-polymorphic."
msgstr ""
"properties_list和SQL <literal>INSERT</literal>语句中的<literal>字段定义"
"(column speficiation)</literal>类似。对参与继承树映射的实体而言，只有直接定义"
"在给定的类级别的属性才能直接在properties_list中使用。超类的属性不被支持；子类"
"的属性无意义。换句话说，<literal>INSERT</literal>天生不支持多态。"

#. Tag: para
#: batch.xml:244
#, no-c-format
msgid ""
"select_statement can be any valid HQL select query, with the caveat that the "
"return types must match the types expected by the insert. Currently, this is "
"checked during query compilation rather than allowing the check to relegate "
"to the database. Note however that this might cause problems between "
"Hibernate <literal>Type</literal>s which are <emphasis>equivalent</emphasis> "
"as opposed to <emphasis>equal</emphasis>. This might cause issues with "
"mismatches between a property defined as a <literal>org.hibernate.type."
"DateType</literal> and a property defined as a <literal>org.hibernate.type."
"TimestampType</literal>, even though the database might not make a "
"distinction or might be able to handle the conversion."
msgstr ""
"select_statement可以是任何合法的HQL选择查询，不过要保证返回类型必须和要插入的"
"类型完全匹配。目前，这一检查是在查询编译的时候进行的，而不是把它交给数据库。"
"注意，在Hibernate<literal>Type</literal>间如果只是<emphasis>等价"
"（equivalent）</emphasis>而非<emphasis>相等(equal)</emphasis>，会导致问题。定"
"义为<literal>org.hibernate.type.DateType</literal>和<literal>org.hibernate."
"type.TimestampType</literal>的两个属性可能会产生类型不匹配错误，虽然数据库级"
"可能不加区分或者可以处理这种转换。"

#. Tag: para
#: batch.xml:256
#, no-c-format
msgid ""
"For the id property, the insert statement gives you two options. You can "
"either explicitly specify the id property in the properties_list (in which "
"case its value is taken from the corresponding select expression) or omit it "
"from the properties_list (in which case a generated value is used). This "
"later option is only available when using id generators that operate in the "
"database; attempting to use this option with any \"in memory\" type "
"generators will cause an exception during parsing. Note that for the "
"purposes of this discussion, in-database generators are considered to be "
"<literal>org.hibernate.id.SequenceGenerator</literal> (and its subclasses) "
"and any implementors of <literal>org.hibernate.id."
"PostInsertIdentifierGenerator</literal>. The most notable exception here is "
"<literal>org.hibernate.id.TableHiLoGenerator</literal>, which cannot be used "
"because it does not expose a selectable way to get its values."
msgstr ""
"对id属性来说,insert语句给你两个选择。你可以明确地在properties_list表中指定id"
"属性（这样它的值是从对应的select表达式中获得），或者在properties_list中省略它"
"（此时使用生成指）。后一种选择只有当使用在数据库中生成值的id产生器时才能使"
"用；如果是“内存”中计算的类型生成器，在解析时会抛出一个异常。注意，为了说明这"
"一问题，数据库产生值的生成器是<literal>org.hibernate.id.SequenceGenerator</"
"literal>（和它的子类），以及任何<literal>org.hibernate.id."
"PostInsertIdentifierGenerator</literal>接口的实现。这儿最值得注意的意外是"
"<literal>org.hibernate.id.TableHiLoGenerator</literal>，它不能在此使用，因为"
"它没有得到其值的途径。"

#. Tag: para
#: batch.xml:271
#, no-c-format
msgid ""
"For properties mapped as either <literal>version</literal> or "
"<literal>timestamp</literal>, the insert statement gives you two options. "
"You can either specify the property in the properties_list (in which case "
"its value is taken from the corresponding select expressions) or omit it "
"from the properties_list (in which case the <literal>seed value</literal> "
"defined by the <literal>org.hibernate.type.VersionType</literal> is used)."
msgstr ""
"对映射为<literal>version</literal> 或 <literal>timestamp</literal>的属性来"
"说，insert语句也给你两个选择，你可以在properties_list表中指定（此时其值从对应"
"的select表达式中获得），或者在properties_list中省略它（此时，使用在"
"<literal>org.hibernate.type.VersionType</literal> 中定义的<literal>seed value"
"(种子值)</literal>）。"

#. Tag: para
#: batch.xml:281
#, no-c-format
msgid "An example HQL <literal>INSERT</literal> statement execution:"
msgstr "执行HQL <literal>INSERT</literal>语句的例子如下："

#. Tag: programlisting
#: batch.xml:285
#, no-c-format
msgid ""
"<![CDATA[Session session = sessionFactory.openSession();\n"
"Transaction tx = session.beginTransaction();\n"
"\n"
"String hqlInsert = \"insert into DelinquentAccount (id, name) select c.id, c."
"name from Customer c where ...\";\n"
"int createdEntities = s.createQuery( hqlInsert )\n"
"        .executeUpdate();\n"
"tx.commit();\n"
"session.close();]]>"
msgstr ""