query_hql.pot

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

# SOME DESCRIPTIVE TITLE.
# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
#
#, fuzzy
msgid ""
msgstr ""
"Project-Id-Version: PACKAGE VERSION\n"
"Report-Msgid-Bugs-To: http://bugs.kde.org\n"
"POT-Creation-Date: 2008-08-14 15:28+0000\n"
"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
"Language-Team: LANGUAGE <[e-mail]>\n"
"MIME-Version: 1.0\n"
"Content-Type: application/x-xml2pot; charset=UTF-8\n"
"Content-Transfer-Encoding: 8bit\n"

#. Tag: title
#: query_hql.xml:29
#, no-c-format
msgid "HQL: The Hibernate Query Language"
msgstr ""

#. Tag: para
#: query_hql.xml:31
#, no-c-format
msgid "Hibernate is equipped with an extremely powerful query language that (quite intentionally) looks very much like SQL. But don't be fooled by the syntax; HQL is fully object-oriented, understanding notions like inheritence, polymorphism and association."
msgstr ""

#. Tag: title
#: query_hql.xml:38
#, no-c-format
msgid "Case Sensitivity"
msgstr ""

#. Tag: para
#: query_hql.xml:40
#, no-c-format
msgid "Queries are case-insensitive, except for names of Java classes and properties. So <literal>SeLeCT</literal> is the same as <literal>sELEct</literal> is the same as <literal>SELECT</literal> but <literal>org.hibernate.eg.FOO</literal> is not <literal>org.hibernate.eg.Foo</literal> and <literal>foo.barSet</literal> is not <literal>foo.BARSET</literal>."
msgstr ""

#. Tag: para
#: query_hql.xml:51
#, no-c-format
msgid "This manual uses lowercase HQL keywords. Some users find queries with uppercase keywords more readable, but we find this convention ugly when embedded in Java code."
msgstr ""

#. Tag: title
#: query_hql.xml:59
#, no-c-format
msgid "The from clause"
msgstr ""

#. Tag: para
#: query_hql.xml:61
#, no-c-format
msgid "The simplest possible Hibernate query is of the form:"
msgstr ""

#. Tag: programlisting
#: query_hql.xml:65
#, no-c-format
msgid "<![CDATA[from eg.Cat]]>"
msgstr ""

#. Tag: para
#: query_hql.xml:67
#, no-c-format
msgid "which simply returns all instances of the class <literal>eg.Cat</literal>. We don't usually need to qualify the class name, since <literal>auto-import</literal> is the default. So we almost always just write:"
msgstr ""

#. Tag: programlisting
#: query_hql.xml:73
#, no-c-format
msgid "<![CDATA[from Cat]]>"
msgstr ""

#. Tag: para
#: query_hql.xml:75
#, no-c-format
msgid "Most of the time, you will need to assign an <emphasis>alias</emphasis>, since you will want to refer to the <literal>Cat</literal> in other parts of the query."
msgstr ""

#. Tag: programlisting
#: query_hql.xml:81 query_hql.xml:396
#, no-c-format
msgid "<![CDATA[from Cat as cat]]>"
msgstr ""

#. Tag: para
#: query_hql.xml:83
#, no-c-format
msgid "This query assigns the alias <literal>cat</literal> to <literal>Cat</literal> instances, so we could use that alias later in the query. The <literal>as</literal> keyword is optional; we could also write:"
msgstr ""

#. Tag: programlisting
#: query_hql.xml:89
#, no-c-format
msgid "<![CDATA[from Cat cat]]>"
msgstr ""

#. Tag: para
#: query_hql.xml:91
#, no-c-format
msgid "Multiple classes may appear, resulting in a cartesian product or \"cross\" join."
msgstr ""

#. Tag: programlisting
#: query_hql.xml:95
#, no-c-format
msgid "<![CDATA[from Formula, Parameter]]>"
msgstr ""

#. Tag: programlisting
#: query_hql.xml:96
#, no-c-format
msgid "<![CDATA[from Formula as form, Parameter as param]]>"
msgstr ""

#. Tag: para
#: query_hql.xml:98
#, no-c-format
msgid "It is considered good practice to name query aliases using an initial lowercase, consistent with Java naming standards for local variables (eg. <literal>domesticCat</literal>)."
msgstr ""

#. Tag: title
#: query_hql.xml:107
#, no-c-format
msgid "Associations and joins"
msgstr ""

#. Tag: para
#: query_hql.xml:109
#, no-c-format
msgid "We may also assign aliases to associated entities, or even to elements of a collection of values, using a <literal>join</literal>."
msgstr ""

#. Tag: programlisting
#: query_hql.xml:114
#, no-c-format
msgid ""
      "<![CDATA[from Cat as cat\n"
      "    inner join cat.mate as mate\n"
      "    left outer join cat.kittens as kitten]]>"
msgstr ""

#. Tag: programlisting
#: query_hql.xml:116
#, no-c-format
msgid "<![CDATA[from Cat as cat left join cat.mate.kittens as kittens]]>"
msgstr ""

#. Tag: programlisting
#: query_hql.xml:118
#, no-c-format
msgid "<![CDATA[from Formula form full join form.parameter param]]>"
msgstr ""

#. Tag: para
#: query_hql.xml:120
#, no-c-format
msgid "The supported join types are borrowed from ANSI SQL"
msgstr ""

#. Tag: literal
#: query_hql.xml:127
#, no-c-format
msgid "inner join"
msgstr ""

#. Tag: literal
#: query_hql.xml:132
#, no-c-format
msgid "left outer join"
msgstr ""

#. Tag: literal
#: query_hql.xml:137
#, no-c-format
msgid "right outer join"
msgstr ""

#. Tag: para
#: query_hql.xml:141
#, no-c-format
msgid "<literal>full join</literal> (not usually useful)"
msgstr ""

#. Tag: para
#: query_hql.xml:147
#, no-c-format
msgid "The <literal>inner join</literal>, <literal>left outer join</literal> and <literal>right outer join</literal> constructs may be abbreviated."
msgstr ""

#. Tag: programlisting
#: query_hql.xml:152
#, no-c-format
msgid ""
      "<![CDATA[from Cat as cat\n"
      "    join cat.mate as mate\n"
      "    left join cat.kittens as kitten]]>"
msgstr ""

#. Tag: para
#: query_hql.xml:154
#, no-c-format
msgid "You may supply extra join conditions using the HQL <literal>with</literal> keyword."
msgstr ""

#. Tag: programlisting
#: query_hql.xml:159
#, no-c-format
msgid ""
      "<![CDATA[from Cat as cat\n"
      "    left join cat.kittens as kitten\n"
      "        with kitten.bodyWeight > 10.0]]>"
msgstr ""

#. Tag: para
#: query_hql.xml:161
#, no-c-format
msgid "In addition, a \"fetch\" join allows associations or collections of values to be initialized along with their parent objects, using a single select. This is particularly useful in the case of a collection. It effectively overrides the outer join and lazy declarations of the mapping file for associations and collections. See <xref linkend=\"performance-fetching\"/> for more information."
msgstr ""

#. Tag: programlisting
#: query_hql.xml:169
#, no-c-format
msgid ""
      "<![CDATA[from Cat as cat\n"
      "    inner join fetch cat.mate\n"
      "    left join fetch cat.kittens]]>"
msgstr ""

#. Tag: para
#: query_hql.xml:171
#, no-c-format
msgid "A fetch join does not usually need to assign an alias, because the associated objects should not be used in the <literal>where</literal> clause (or any other clause). Also, the associated objects are not returned directly in the query results. Instead, they may be accessed via the parent object. The only reason we might need an alias is if we are recursively join fetching a further collection:"
msgstr ""

#. Tag: programlisting
#: query_hql.xml:179
#, no-c-format
msgid ""
      "<![CDATA[from Cat as cat\n"
      "    inner join fetch cat.mate\n"
      "    left join fetch cat.kittens child\n"
      "    left join fetch child.kittens]]>"
msgstr ""

#. Tag: para
#: query_hql.xml:181
#, no-c-format
msgid "Note that the <literal>fetch</literal> construct may not be used in queries called using <literal>iterate()</literal> (though <literal>scroll()</literal> can be used). Nor should <literal>fetch</literal> be used together with <literal>setMaxResults()</literal> or <literal>setFirstResult()</literal> as these operations are based on the result rows, which usually contain duplicates for eager collection fetching, hence, the number of rows is not what you'd expect. Nor may <literal>fetch</literal> be used together with an ad hoc <literal>with</literal> condition. It is possible to create a cartesian product by join fetching more than one collection in a query, so take care in this case. Join fetching multiple collection roles also sometimes gives unexpected results for bag mappings, so be careful about how you formulate your queries in this case. Finally, note that <literal>full join fetch</literal> and <literal>right join fetch</literal> are not meaningful."
msgstr ""

#. Tag: para
#: query_hql.xml:196
#, no-c-format
msgid "If you are using property-level lazy fetching (with bytecode instrumentation), it is possible to force Hibernate to fetch the lazy properties immediately (in the first query) using <literal>fetch all properties</literal>."
msgstr ""

#. Tag: programlisting
#: query_hql.xml:202
#, no-c-format
msgid "<![CDATA[from Document fetch all properties order by name]]>"
msgstr ""

#. Tag: programlisting
#: query_hql.xml:203
#, no-c-format
msgid "<![CDATA[from Document doc fetch all properties where lower(doc.name) like '%cats%']]>"
msgstr ""

#. Tag: title
#: query_hql.xml:208
#, no-c-format
msgid "Forms of join syntax"
msgstr ""

#. Tag: para
#: query_hql.xml:210
#, no-c-format
msgid "HQL supports two forms of association joining: <literal>implicit</literal> and <literal>explicit</literal>."
msgstr ""

#. Tag: para
#: query_hql.xml:214
#, no-c-format
msgid "The queries shown in the previous section all use the <literal>explicit</literal> form where the join keyword is explicitly used in the from clause. This is the recommended form."
msgstr ""

#. Tag: para
#: query_hql.xml:219
#, no-c-format
msgid "The <literal>implicit</literal> form does not use the join keyword. Instead, the associations are \"dereferenced\" using dot-notation. <literal>implicit</literal> joins can appear in any of the HQL clauses. <literal>implicit</literal> join result in inner joins in the resulting SQL statement."
msgstr ""

#. Tag: programlisting
#: query_hql.xml:226
#, no-c-format
msgid "<![CDATA[from Cat as cat where cat.mate.name like '%s%']]>"
msgstr ""

#. Tag: title
#: query_hql.xml:230
#, no-c-format
msgid "Refering to identifier property"
msgstr ""

#. Tag: para
#: query_hql.xml:232
#, no-c-format
msgid "There are, generally speaking, 2 ways to refer to an entity's identifier property:"
msgstr ""

#. Tag: para
#: query_hql.xml:237
#, no-c-format
msgid "The special property (lowercase) <literal>id</literal> may be used to reference the identifier property of an entity <emphasis>provided that entity does not define a non-identifier property named id</emphasis>."
msgstr ""

#. Tag: para
#: query_hql.xml:244
#, no-c-format
msgid "If the entity defines a named identifier property, you may use that property name."
msgstr ""

#. Tag: para
#: query_hql.xml:250
#, no-c-format
msgid "References to composite identifier properties follow the same naming rules. If the entity has a non-identifier property named id, the composite identifier property can only be referenced by its defined named; otherwise, the special <literal>id</literal> property can be used to rerference the identifier property."
msgstr ""

#. Tag: para
#: query_hql.xml:257
#, no-c-format
msgid "Note: this has changed significantly starting in version 3.2.2. In previous versions, <literal>id</literal> <emphasis>always</emphasis> referred to the identifier property no matter what its actual name. A ramification of that decision was that non-identifier properties named <literal>id</literal> could never be referenced in Hibernate queries."
msgstr ""

#. Tag: title
#: query_hql.xml:266
#, no-c-format
msgid "The select clause"
msgstr ""

#. Tag: para
#: query_hql.xml:268
#, no-c-format
msgid "The <literal>select</literal> clause picks which objects and properties to return in the query result set. Consider:"
msgstr ""

#. Tag: programlisting
#: query_hql.xml:273
#, no-c-format
msgid ""
      "<![CDATA[select mate\n"
      "from Cat as cat\n"
      "    inner join cat.mate as mate]]>"
msgstr ""

#. Tag: para
#: query_hql.xml:275
#, no-c-format
msgid "The query will select <literal>mate</literal>s of other <literal>Cat</literal>s. Actually, you may express this query more compactly as:"
msgstr ""

#. Tag: programlisting
#: query_hql.xml:280
#, no-c-format
msgid "<![CDATA[select cat.mate from Cat cat]]>"
msgstr ""

#. Tag: para
#: query_hql.xml:282
#, no-c-format
msgid "Queries may return properties of any value type including properties of component type:"
msgstr ""

#. Tag: programlisting
#: query_hql.xml:286
#, no-c-format
msgid ""
      "<![CDATA[select cat.name from DomesticCat cat\n"
      "where cat.name like 'fri%']]>"
msgstr ""

#. Tag: programlisting
#: query_hql.xml:288
#, no-c-format
msgid "<![CDATA[select cust.name.firstName from Customer as cust]]>"
msgstr ""

#. Tag: para
#: query_hql.xml:290
#, no-c-format
msgid "Queries may return multiple objects and/or properties as an array of type <literal>Object[]</literal>,"
msgstr ""

#. Tag: programlisting
#: query_hql.xml:295
#, no-c-format
msgid ""
      "<![CDATA[select mother, offspr, mate.name\n"
      "from DomesticCat as mother\n"
      "    inner join mother.mate as mate\n"
      "    left outer join mother.kittens as offspr]]>"
msgstr ""

#. Tag: para
#: query_hql.xml:297
#, no-c-format
msgid "or as a <literal>List</literal>,"
msgstr ""

#. Tag: programlisting
#: query_hql.xml:301
#, no-c-format
msgid ""
      "<![CDATA[select new list(mother, offspr, mate.name)\n"
      "from DomesticCat as mother\n"
      "    inner join mother.mate as mate\n"
      "    left outer join mother.kittens as offspr]]>"
msgstr ""

#. Tag: para
#: query_hql.xml:303
#, no-c-format
msgid "or as an actual typesafe Java object,"
msgstr ""

#. Tag: programlisting
#: query_hql.xml:307
#, no-c-format
msgid ""
      "<![CDATA[select new Family(mother, mate, offspr)\n"
      "from DomesticCat as mother\n"
      "    join mother.mate as mate\n"
      "    left join mother.kittens as offspr]]>"
msgstr ""

#. Tag: para
#: query_hql.xml:309
#, no-c-format
msgid "assuming that the class <literal>Family</literal> has an appropriate constructor."
msgstr ""

#. Tag: para
#: query_hql.xml:313
#, no-c-format
msgid "You may assign aliases to selected expressions using <literal>as</literal>:"