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From: <one...@us...> - 2003-03-02 13:03:17
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Update of /cvsroot/hibernate/Hibernate2/doc/reference/src
In directory sc8-pr-cvs1:/tmp/cvs-serv7909
Modified Files:
query_language.xml
Log Message:
documented latest QL changes
Index: query_language.xml
===================================================================
RCS file: /cvsroot/hibernate/Hibernate2/doc/reference/src/query_language.xml,v
retrieving revision 1.4
retrieving revision 1.5
diff -C2 -d -r1.4 -r1.5
*** query_language.xml 1 Mar 2003 13:02:19 -0000 1.4
--- query_language.xml 2 Mar 2003 13:03:15 -0000 1.5
***************
*** 13,18 ****
<literal>net.sf.hibernate.eg.FOO</literal> is not
<literal>net.sf.hibernate.eg.Foo</literal> and
! <literal>foo.Bar</literal> is not
! <literal>foo.BAR</literal>.
</para>
</sect1>
--- 13,18 ----
<literal>net.sf.hibernate.eg.FOO</literal> is not
<literal>net.sf.hibernate.eg.Foo</literal> and
! <literal>foo.barSet</literal> is not
! <literal>foo.BARSET</literal>.
</para>
</sect1>
***************
*** 26,48 ****
</para>
! <programlisting><![CDATA[from cat in class eg.Cat]]></programlisting>
<para>
which simply returns all instances of the class <literal>eg.Cat</literal>. The
query assigns the alias <literal>cat</literal> to <literal>Cat</literal>
! instances, so we could use that alias later in the query.
</para>
</sect1>
<sect1 id="query-language-s3">
<title>The select clause</title>
<para>
! A multipart <literal>from</literal> clause is possible. The <literal>select</literal>
! clause picks which classes to return in the result set. Consider:
</para>
! <programlisting><![CDATA[select mate from cat in class eg.Cat, mate in class eg.Cat
! where mate = cat.mate]]></programlisting>
<para>
--- 26,112 ----
</para>
! <programlisting><![CDATA[from eg.Cat as cat]]></programlisting>
<para>
which simply returns all instances of the class <literal>eg.Cat</literal>. The
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:
</para>
+
+ <programlisting><![CDATA[from eg.Cat cat]]></programlisting>
+
+ <para>
+ Multiple classes may appear, resulting in a cartesian product or "cross" join.
+ </para>
+
+ <programlisting><![CDATA[from Formula as form, Parameter as param]]></programlisting>
+
</sect1>
<sect1 id="query-language-s3">
+ <title>Associations and joins</title>
+
+ <para>
+ We may also define aliases to associated entities using a <literal>join</literal>.
+ </para>
+
+ <programlisting><![CDATA[from eg.Cat as cat
+ inner join cat.mate as mate
+ left outer join cat.kittens as kitten
+
+ from eg.Cat as cat left join cat.mate.kittens as kittens
+
+ from Formula form full join form.parameter param]]></programlisting>
+
+ <para>
+ The supported join types are borrowed from ANSI SQL
+ </para>
+
+ <itemizedlist spacing="compact">
+ <listitem>
+ <para>
+ <literal>inner join</literal>
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <literal>left outer join</literal>
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <literal>right outer join</literal> (not recommended)
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <literal>full join</literal> (not usually useful)
+ </para>
+ </listitem>
+ </itemizedlist>
+
+ <para>
+ The <literal>inner join</literal>, <literal>left outer join</literal> and
+ <literal>right outer join</literal> constructs may be abbreviated.
+ </para>
+
+ <programlisting><![CDATA[from eg.Cat as cat
+ join cat.mate as mate
+ left join cat.kittens as kitten]]></programlisting>
+
+ </sect1>
+
+ <sect1 id="query-language-s4">
<title>The select clause</title>
<para>
! The <literal>select</literal> clause picks which objects and properties to return in
! the query result set. Consider:
</para>
! <programlisting><![CDATA[select mate
! from eg.Cat cat
! inner join cat.mate cat]]></programlisting>
<para>
***************
*** 51,55 ****
</para>
! <programlisting><![CDATA[select cat.mate from cat in class eg.Cat]]></programlisting>
<para>
--- 115,119 ----
</para>
! <programlisting><![CDATA[select cat.mate from eg.Cat cat]]></programlisting>
<para>
***************
*** 58,62 ****
</para>
! <programlisting><![CDATA[select elements(cat.kittens) from cat in class eg.Cat]]></programlisting>
<para>
--- 122,126 ----
</para>
! <programlisting><![CDATA[select elements(cat.kittens) from eg.Cat cat]]></programlisting>
<para>
***************
*** 64,90 ****
</para>
! <programlisting><![CDATA[select cat.name from cat in class eg.DomesticCat
where cat.name like 'fri%'
! select cust.name.firstName from cust in class Customer]]></programlisting>
<para>
! You may select multiple objects (Hibernate will return them in an array of type
! <literal>Object[]</literal>)
</para>
! <programlisting><![CDATA[select mother, offspr
! from mother in class eg.DomesticCat, offspr in class eg.Cat
! where offspr in elements(mother.kittens)]]></programlisting>
<para>
! Queryies may even return aggregate functions of properties. Collections may also appear
! inside aggregate functions in the <literal>select</literal> clause.
</para>
<programlisting><![CDATA[select avg(cat.weight), sum(cat.weight), max(cat.weight), count(cat)
! from cat in class eg.Cat
! select cat, count( elements(cat.kittens) ) from cat in class eg.Cat group by cat]]></programlisting>
<para>
--- 128,177 ----
</para>
! <programlisting><![CDATA[select cat.name from eg.DomesticCat cat
where cat.name like 'fri%'
! select cust.name.firstName from Customer as cust]]></programlisting>
<para>
! Queries may return multiple objects and/or properties as an array of type
! <literal>Object[]</literal>
</para>
! <programlisting><![CDATA[select cat, offspr, mate.name
! from eg.DomesticCat as mother
! inner join mother.mate as mate
! left outer join mother.kittens as offspr]]></programlisting>
!
! <para>
! or as an actual typesafe Java object
! </para>
!
! <programlisting><![CDATA[select new Family(cat, mate, offspr)
! from eg.DomesticCat as mother
! join mother.mate as mate
! left join mother.kittens as offspr]]></programlisting>
!
! <para>
! assuming that the class <literal>Family</literal> has an appropriate constructor.
! </para>
!
! </sect1>
+ <sect1 id="query-language-s4a">
+ <title>Aggregate functions</title>
<para>
! Queryies may even return aggregate functions of properties.
</para>
<programlisting><![CDATA[select avg(cat.weight), sum(cat.weight), max(cat.weight), count(cat)
! from eg.Cat cat></programlisting>
! <para>
! Collections may also appear inside aggregate functions in the <literal>select</literal>
! clause.
! </para>
!
! <programlisting><![CDATA[select cat, count( elements(cat.kittens) )
! from eg.Cat cat group by cat]]></programlisting>
<para>
***************
*** 114,140 ****
the same semantics as in SQL.
</para>
! <programlisting><![CDATA[select distinct cat.name from cat in class eg.Cat]]></programlisting>
</sect1>
! <sect1 id="query-language-s3b">
<title>polymorphism</title>
<para>
A query like:
</para>
! <programlisting><![CDATA[from cat in class eg.Cat]]></programlisting>
<para>
returns instances not only of <literal>Cat</literal>, but also of subclasses like
! <literal>DomesticCat</literal>. Hibernate queries may name <emphasis>any</emphasis>
! Java class or interface in the <literal>from</literal> clause. The query will
! return instances of all persistent classes that extend that class or implement
! the interface. The following query would return all persistent objects:
</para>
! <programlisting><![CDATA[from o in class java.lang.Object]]></programlisting>
<para>
The interface <literal>Named</literal> might be implemented by various persistent
classes:
</para>
! <programlisting><![CDATA[from n in class eg.Named, m in class eg.Named where n.name = m.name]]></programlisting>
<para>
Note that these last two queries will require more than one SQL <literal>SELECT</literal>. This
--- 201,233 ----
the same semantics as in SQL.
</para>
! <programlisting><![CDATA[select distinct cat.name from eg.Cat cat
!
! select count(distinct cat.name), count(cat) from eg.Cat cat]]></programlisting>
</sect1>
! <sect1 id="query-language-s4b">
<title>polymorphism</title>
<para>
A query like:
</para>
! <programlisting><![CDATA[from eg.Cat as cat]]></programlisting>
<para>
returns instances not only of <literal>Cat</literal>, but also of subclasses like
! <literal>DomesticCat</literal>. Hibernate queries may name <emphasis>any</emphasis> Java
! class or interface in the <literal>from</literal> clause. The query will return instances
! of all persistent classes that extend that class or implement the interface. The following
! query would return all persistent objects:
</para>
!
! <programlisting><![CDATA[from java.lang.Object o]]></programlisting>
!
<para>
The interface <literal>Named</literal> might be implemented by various persistent
classes:
</para>
!
! <programlisting><![CDATA[from eg.Named n, eg.Named m where n.name = m.name]]></programlisting>
!
<para>
Note that these last two queries will require more than one SQL <literal>SELECT</literal>. This
***************
*** 142,173 ****
(It also means you can't call these queries using <literal>Query.scroll()</literal>.)
</para>
</sect1>
- <sect1 id="query-language-s4">
- <title>from collections</title>
-
- <para>
- You can select entities (but not values) from a collection
- </para>
-
- <programlisting><![CDATA[select kitten from
- cat in class eg.Cat,
- kitten in elements(cat.kittens)]]></programlisting>
-
- <para>
- The <literal>elements</literal> function accesses element set of the collection.
- </para>
- </sect1>
-
-
<sect1 id="query-language-s5">
<title>The where clause</title>
<para>
! The <literal>where</literal> clause allows you to narrow the list
! of instances returned.
</para>
! <programlisting><![CDATA[from cat in class eg.Cat where cat.name='Fritz']]></programlisting>
<para>
--- 235,249 ----
(It also means you can't call these queries using <literal>Query.scroll()</literal>.)
</para>
+
</sect1>
<sect1 id="query-language-s5">
<title>The where clause</title>
<para>
! The <literal>where</literal> clause allows you to narrow the list of instances returned.
</para>
! <programlisting><![CDATA[from eg.Cat as cat where cat.name='Fritz']]></programlisting>
<para>
***************
*** 175,179 ****
</para>
! <programlisting><![CDATA[select foo from foo in class eg.Foo, bar in class eg.Bar
where foo.startDate = bar.date]]></programlisting>
--- 251,255 ----
</para>
! <programlisting><![CDATA[select foo from eg.Foo foo, eg.Bar bar
where foo.startDate = bar.date]]></programlisting>
***************
*** 187,198 ****
</para>
! <programlisting><![CDATA[from cat in class eg.Cat where cat.mate.name is not null]]></programlisting>
<para>
! This query translates to an SQL query with a table join. If you were to write
something like
</para>
! <programlisting><![CDATA[from foo in class eg.Foo
where foo.bar.baz.customer.address.city is not null]]></programlisting>
--- 263,274 ----
</para>
! <programlisting><![CDATA[from eg.Cat cat where cat.mate.name is not null]]></programlisting>
<para>
! This query translates to an SQL query with a table (inner) join. If you were to write
something like
</para>
! <programlisting><![CDATA[from eg.Foo foo
where foo.bar.baz.customer.address.city is not null]]></programlisting>
***************
*** 206,212 ****
</para>
! <programlisting><![CDATA[from cat in class eg.Cat, rival in class eg.Cat where cat.mate = rival.mate
! select cat, mate from cat in class eg.Cat, mate in class eg.Cat
where cat.mate = mate]]></programlisting>
--- 282,288 ----
</para>
! <programlisting><![CDATA[from eg.Cat cat, eg.Cat rival where cat.mate = rival.mate
! select cat, mate from eg.Cat cat, eg.Cat mate
where cat.mate = mate]]></programlisting>
***************
*** 216,222 ****
</para>
! <programlisting><![CDATA[from cat in class eg.Cat where cat.id = 123
! from cat in class eg.Cat where cat.mate.id = 69]]></programlisting>
<para>
--- 292,298 ----
</para>
! <programlisting><![CDATA[from eg.Cat as cat where cat.id = 123
! from eg.Cat as cat where cat.mate.id = 69]]></programlisting>
<para>
***************
*** 230,237 ****
</para>
! <programlisting><![CDATA[from person in class bank.Person
where person.id.country = 'AU' and person.id.medicareNumber = 123456
! from account in class bank.Account
where account.owner.id.country = 'AU' and account.owner.id.medicareNumber = 123456]]></programlisting>
--- 306,313 ----
</para>
! <programlisting><![CDATA[from bank.Person person
where person.id.country = 'AU' and person.id.medicareNumber = 123456
! from bank.Account account
where account.owner.id.country = 'AU' and account.owner.id.medicareNumber = 123456]]></programlisting>
***************
*** 246,250 ****
</para>
! <programlisting><![CDATA[from cat in class eg.Cat where cat.class = eg.DomesticCat]]></programlisting>
<para>
--- 322,326 ----
</para>
! <programlisting><![CDATA[from eg.Cat cat where cat.class = eg.DomesticCat]]></programlisting>
<para>
***************
*** 334,340 ****
</para>
! <programlisting><![CDATA[from cat in class eg.DomesticCat where cat.name between 'A' and 'B'
! from cat in class eg.DomesticCat where cat.name in ( 'Foo', 'Bar', Baz" )]]></programlisting>
<para>
--- 410,416 ----
</para>
! <programlisting><![CDATA[from eg.DomesticCat cat where cat.name between 'A' and 'B'
! from eg.DomesticCat cat where cat.name in ( 'Foo', 'Bar', Baz" )]]></programlisting>
<para>
***************
*** 342,348 ****
</para>
! <programlisting><![CDATA[from cat in class eg.DomesticCat where cat.name not between 'A' and 'B'
! from cat in class eg.DomesticCat where cat.name not in ( 'Foo', 'Bar', Baz" )]]></programlisting>
<para>
--- 418,424 ----
</para>
! <programlisting><![CDATA[from eg.DomesticCat cat where cat.name not between 'A' and 'B'
! from eg.DomesticCat cat where cat.name not in ( 'Foo', 'Bar', Baz" )]]></programlisting>
<para>
***************
*** 352,359 ****
<para>
! You may test the size of a collection with the special property <literal>size</literal>
</para>
! <programlisting><![CDATA[from cat in class eg.Cat where cat.kittens.size > 0]]></programlisting>
<para>
--- 428,438 ----
<para>
! You may test the size of a collection with the special property <literal>size</literal>, or
! the special <literal>size()</literal> function.
</para>
! <programlisting><![CDATA[from eg.Cat cat where cat.kittens.size > 0
!
! from eg.Cat cat where size(cat.kittens) > 0]]></programlisting>
<para>
***************
*** 364,368 ****
</para>
! <programlisting><![CDATA[from cal in class Calendar where cal.holidays.maxElement > current date]]></programlisting>
<para>
--- 443,447 ----
</para>
! <programlisting><![CDATA[from Calendar cal where cal.holidays.maxElement > current date]]></programlisting>
<para>
***************
*** 370,376 ****
</para>
! <programlisting><![CDATA[from order in class Order where maxindex(order.items) > 100
! from order in class Order where size(order.items) > 100]]></programlisting>
<para>
--- 449,455 ----
</para>
! <programlisting><![CDATA[from Order order where maxindex(order.items) > 100
! from Order order where minelement(order.items) > 10000]]></programlisting>
<para>
***************
*** 380,395 ****
</para>
! <programlisting><![CDATA[select mother from mother in class eg.Cat, kit in class eg.Cat
where kit in elements(foo.kittens)
! select p from list in class eg.NameList, p in class eg.Person
where p.name = some elements(list.names)
! from cat in class eg.Cat where exists elements(cat.kittens)
! from p in class eg.Player where 3 > all elements(p.scores)
! from show in class eg.Show
! where 'fizard' in indices(show.acts)]]></programlisting>
<para>
--- 459,473 ----
</para>
! <programlisting><![CDATA[select mother from eg.Cat as mother, eg.Cat as kit
where kit in elements(foo.kittens)
! select p from eg.NameList list, eg.Person p
where p.name = some elements(list.names)
! from eg.Cat cat where exists elements(cat.kittens)
! from eg.Player p where 3 > all elements(p.scores)
! from eg.Show show where 'fizard' in indices(show.acts)]]></programlisting>
<para>
***************
*** 406,415 ****
</para>
</listitem>
! <listitem>
<para>
in a <literal>from</literal> clause: only <literal>elements</literal> makes sense ... and
only for a collection of entities
</para>
! </listitem>
<listitem>
<para>
--- 484,493 ----
</para>
</listitem>
! <!--<listitem>
<para>
in a <literal>from</literal> clause: only <literal>elements</literal> makes sense ... and
only for a collection of entities
</para>
! </listitem>-->
<listitem>
<para>
***************
*** 424,437 ****
</para>
! <programlisting><![CDATA[from order in class Order where order.items[0].id = 1234
! select person from person in class Person, calendar in class Calendar
where calendar.holidays['national day'] = person.birthDay
and person.nationality.calendar = calendar
! select item from item in class Item, order in class Order
where order.items[ order.deliveredItemIndices[0] ] = item and order.id = 11
! select item from item in class Item, order in class Order
where order.items[ maxindex(order.items) ] = item and order.id = 11]]></programlisting>
--- 502,515 ----
</para>
! <programlisting><![CDATA[from Order order where order.items[0].id = 1234
! select person from Person person, Calendar calendar
where calendar.holidays['national day'] = person.birthDay
and person.nationality.calendar = calendar
! select item from Item item, Order order
where order.items[ order.deliveredItemIndices[0] ] = item and order.id = 11
! select item from Item item, Order order
where order.items[ maxindex(order.items) ] = item and order.id = 11]]></programlisting>
***************
*** 440,444 ****
</para>
! <programlisting><![CDATA[select item from item in class Item, order in class Order
where order.items[ size(order.items) - 1 ] = item]]></programlisting>
--- 518,522 ----
</para>
! <programlisting><![CDATA[select item from Item item, Order order
where order.items[ size(order.items) - 1 ] = item]]></programlisting>
***************
*** 447,451 ****
</para>
! <programlisting><![CDATA[from cat in class eg.DomesticCat where upper(cat.name) like 'FRI%']]></programlisting>
<para>
--- 525,529 ----
</para>
! <programlisting><![CDATA[from eg.DomesticCat cat where upper(cat.name) like 'FRI%']]></programlisting>
<para>
***************
*** 455,461 ****
<programlisting><![CDATA[select cust
! from prod in class Product,
! store in class Store,
! cust in store.customers
where prod.name = 'widget'
and store.location.name in ( 'Melbourne', 'Sydney' )
--- 533,539 ----
<programlisting><![CDATA[select cust
! from Product prod,
! Store store
! inner join store.customers cust
where prod.name = 'widget'
and store.location.name in ( 'Melbourne', 'Sydney' )
***************
*** 494,498 ****
</para>
! <programlisting><![CDATA[from cat in class eg.DomesticCat
order by cat.name asc, cat.weight desc, cat.birthdate]]></programlisting>
--- 572,576 ----
</para>
! <programlisting><![CDATA[from eg.DomesticCat cat
order by cat.name asc, cat.weight desc, cat.birthdate]]></programlisting>
***************
*** 511,518 ****
</para>
! <programlisting><![CDATA[select cat.color, sum(cat.weight), count(cat) from cat in class eg.Cat
group by cat.color
! select foo.id, avg( elements(foo.names) ), max( indices(foo.names) ) from foo in class eg.Foo
group by foo.id]]></programlisting>
--- 589,596 ----
</para>
! <programlisting><![CDATA[select cat.color, sum(cat.weight), count(cat) from eg.Cat cat
group by cat.color
! select foo.id, avg( elements(foo.names) ), max( indices(foo.names) ) from eg.Foo foo
group by foo.id]]></programlisting>
***************
*** 522,526 ****
<para>A <literal>having</literal> clause is also allowed.</para>
! <programlisting><![CDATA[select cat.color, sum(cat.weight), count(cat) from foo in class eg.Foo
group by cat.color having cat.color in (eg.Color.TABBY, eg.Color.BLACK)]]></programlisting>
--- 600,604 ----
<para>A <literal>having</literal> clause is also allowed.</para>
! <programlisting><![CDATA[select cat.color, sum(cat.weight), count(cat) from eg.Cat cat
group by cat.color having cat.color in (eg.Color.TABBY, eg.Color.BLACK)]]></programlisting>
***************
*** 536,547 ****
</para>
! <programlisting><![CDATA[from fatcat in class eg.Cat where fatcat.weight >
! ( select avg(cat.weight) from cat in class eg.DomesticCat )
! from cat in class eg.DomesticCat where cat.name =
! some( select list.name from list in class eg.NameList )
! from cat in class eg.Cat where not exists
! ( from mate in class eg.Cat where mate.mate = cat )]]></programlisting>
</sect1>
--- 614,625 ----
</para>
! <programlisting><![CDATA[from eg.Cat fatcat where fatcat.weight >
! ( select avg(cat.weight) from eg.DomesticCat cat )
! from eg.DomesticCat cat where cat.name =
! some( select list.name from eg.NameList list )
! from eg.Cat cat where not exists
! ( from eg.Cat mate where mate.mate = cat )]]></programlisting>
</sect1>
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