java - Implementing multiple JOINS in HQL -

-

i'm trying implement hql query. i've been able implement in sql - i'm little more familiar with. keep getting hung on inner joins.

the classes implemented this...

class item  class component extends item     private item parentitem;  class assembly extends item

so far, have hql...

select item.blah, comp.blah, assembly.blah component comp left outer join comp.parentitem item, assembly assembly  item.parentitem = assembly

this works - except need last 3 lines left outer join rather mutually exclusive condition. i've tried implement in number of ways - keep running mapping problems.

<hibernate-mapping>     <class lazy="false" name="com.kcp.common.domain.inventory.item"    table="w_inv_inv_item" where="deleted=0">         <joined-subclass lazy="false" name="com.kcp.common.domain.inventory.component" table="w_inv_inv_component">          <key>            <column name="id">                <comment>primary , foreign key w_inv_inv_item.</comment>             </column>          </key>          <many-to-one cascade="all" class="com.kcp.common.domain.inventory.item" name="parentitem" outer-join="true">               <column name="parent_item_id">                 <comment>foreign key identifying item component assembled.</comment>               </column>          </many-to-one>        </joined-subclass>          <joined-subclass lazy="false" name="com.kcp.common.domain.inventory.assembly" table="w_inv_inv_major_assembly">              <key>             <column name="id">               <comment>primary , foreign key w_inv_inv_item.</comment>             </column>           </key>     </class>  </hibernate-mapping>

also - got work in sql so...

from dbo.w_inv_inv_item item inner join dbo.w_inv_inv_component comp on item.id = comp.id left outer join dbo.w_inv_inv_item parentinv on comp.parent_item_id = parentinv.id left outer join dbo.w_inv_inv_major_assembly parentma on comp.parent_item_id = parentma.id

if include left join condition in clause, act inner join.

if item optional, item.parentitem has optional too, need include in left join.

that hql query generate horrible sql query , should optimize anyway.

try this:

select     i.blah,     c.blah component c left join c.parentitem left join i.parentitem p      p null or p.class = 'assembly'    class item  class component extends item     private item parentitem;  class assembly extends item

Comments

Post a Comment

Popular posts from this blog

node.js - Mongoose: Cast to ObjectId failed for value on newly created object after setting the value -

-
this question has answer here: what's mongoose error cast objectid failed value xxx @ path “_id”? 7 answers even though has been asked many times because entity has no valid objectid field. i came across situation objectid set value can casted objectid still error. the schema: var serviceschema = parammongoose.schema({ servicename:{ type: parammongoose.schema.types.objectid , ref: 'servicenames',required:true } }); pseudo code: servicefromdb=new service({servicename:'some name'}); servicefromdb.servicename='000000000000000000000001'; servicefromdb.save(function(paramerror,paramdata){ if(paramerror){ console.log('but but...',servicefromdb,paramerror) } }); the output of code is: but but... { servicename: 000000000000000000000001, _id: 55079a90286f49280364f78b } { [casterror: cast objectid faile...
Read more

gradle error "Cannot convert the provided notation to a File or URI" -

-
i have defined 2 system properties in gradle.properties: systemprop.builddir=build systemprop.cfgdir=build\\cfg and have following task defined in build.gradle: task clean(group:'clean',description:'clean project') << { ant.sequential { delete(dir: system.properties.builddir) mkdir(dir: system.properties.builddir) delete(dir: system.properties.cfgdir) mkdir(dir: system.properties.cfgdir) } } this generates following error: execution failed task ':clean'. > cannot convert provided notation file or uri: {dir=build}. following types/formats supported: - string or charsequence path, e.g 'src/main/java' or '/usr/include' - string or charsequence uri, e.g 'file:/usr/include' - file instance. - uri or url instance. but equivalent block of code not generate error , works expected: task clean(group:'clean',description:'clean project') << { ...
Read more

python - NameError: name 'subprocess' is not defined -

-
i'm trying make rng website: http://jamesdotcom.com/?p=417 . when run following code: captureimage = subprocess.popen( [ "fswebcam", "-r", "356x292", "-d", "/dev/video0", "static.jpg", "--skip", "10" ], stdout=devnull, stderr=devnull) captureimage.communicate() i following error message: nameerror: name 'subprocess' not defined what should do? thanks have imported first? import subprocess captureimage = subprocess.popen(["fswebcam", ...) subprocess included in python standard library since python 2.4. should not necessary install it.
Read more