I am trying to add a where clause to a many-to-many property I have defined in one of my objects. I must be doing something wrong though because I keep getting hibernate errors saying that the column doesn't exist.
in the template cfc:
<cfproperty
name="Settings"
fieldtype="many-to-many"
cfc="Setting"
linktable="settings_templates"
fkcolumn="templateID"
inversejoincolumn="settingsId"
where="deleted='false'"
>
In the settings cfc:
<cfproperty
name="templates"
fieldtype="many-to-many"
cfc="Template"
linktable="settings_templates"
fkcolumn="settingsId"
inversejoincolumn="templateID"
where="deleted='false'"
>
The error I am getting is:
08/02 16:06:27 [jrpp-170] HIBERNATE ERROR - [Macromedia][SQLServer
JDBC Driver][SQLServer]Invalid column name 'deleted'.
Can anyone see what I am doing wrong? there is a deleted column in both tables, but not in the link table.
The where property behavior for many-to-many is very strange...
In order to debug this, activate the Hibernate logging is primordial.
Refer you to this post: http://www.rupeshk.org/blog/index.php/2009/07/coldfusion-orm-how-to-log-sql/
Take this example:
Article.cfc
/**
* #output false
* #persistent true
* #table article
*/
component {
property name="id" fieldtype="id";
property name="title";
property
name="tags" singularname="tag"
fieldtype="many-to-many" cfc="Tag" linktable="link_article_tag" fkcolumn="articleId"
inversejoincolumn="tagId" where=" deleted = 0 "
;
}
Tag.cfc
/**
* #output false
* #persistent true
* #table tag
*/
component {
property name="id" fieldtype="id";
property name="name";
property name="deleted" dbdefault="0";
property
name="articles" singularname="article"
fieldtype="many-to-many" cfc="Article" linktable="link_article_tag" fkcolumn="tagId"
inversejoincolumn="articleId"
;
}
When I try to list all articles like this ormExecuteQuery('from Article'), see what is appened in the hibernate logs:
select
tags0_.articleId as articleId6_1_,
tags0_.tagId as tagId1_,
tag1_.id as id0_0_,
tag1_.name as name0_0_,
tag1_.deleted as deleted0_0_
from
link_article_tag tags0_
inner join
tag tag1_
on tags0_.tagId=tag1_.id
where
tags0_.deleted = 0
Damned! WTF :| tags0_ == join table ... You see what's wrong?
In order to understand this behavior, I'm going to activate HBMXML generation in Application.cfc with this.ormSettings.saveMapping = true
Here is the files:
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class entity-name="Tag" lazy="true"
name="cfc:www.app.models.test.Tag" table="tag">
<id name="id" type="string">
<column length="255" name="id"/>
</id>
<property name="name" type="string">
<column name="name"/>
</property>
<property name="deleted" type="string">
<column default="0" name="deleted"/>
</property>
<bag name="articles" table="link_article_tag">
<key column="tagId"/>
<many-to-many class="cfc:www.app.models.test.Article" column="articleId"/>
</bag>
</class>
</hibernate-mapping>
What we can see: The where attribute is set at the bag level, not at the to many-to-many. If I edit like this:
<bag name="tags" table="link_article_tag">
<key column="articleId"/>
<many-to-many class="cfc:www.app.models.test.Tag" column="tagId" where=" deleted = 0 "/>
</bag>
The generated SQL become:
select
tags0_.articleId as articleId62_1_,
tags0_.tagId as tagId1_,
tag1_.id as id59_0_,
tag1_.name as name59_0_,
tag1_.deleted as deleted59_0_
from
link_article_tag tags0_
inner join
tag tag1_
on tags0_.tagId=tag1_.id
where
tag1_.deleted = 0
This method works but is not good for code maintenance and readability.
If anyone has a better solution, I'm interested.
So far, the only way around this that I have found is to override the getter using ORMExecuteQuery(). There I can query the objects directly and look for things such as this. Personally, I prefer to work in cfscript, so my code would look something like this:
public array function getSettings() {
return ORMExecuteQuery("SELECT s FROM template t JOIN t.settings s WHERE t.id=:id AND s.deleted=:deleted", {
deleted=false, id=this.getId()
});
}
N.B. – EXAMPLE NOT TESTED
Of course, you don't have to use the parameters as I have, you could just use deleted=false, but that's up to you (I like using parameters, personally).
Also, don't forget the singularName attribute on many-to-many properties.
On a related note, I've had issues using properties on both objects. You really only need to use them on the template object, in this case. Think about it this way: A template needs to know its settings, but the settings don't need to know about the template they belong to – using properties on both objects in this way can lead to errors, in some cases.
Related
I am trying to retrieve the count of items allocated to a container in my hbm file. I've done a bit of digging and managed to get my hbm code this far (below!). I want the count to be retrieved every time a container object is queried. I could use an interceptor but I assume there's a better way. Am I on the right track or should I use a different strategy to get the count loaded up?
Thanks.
P.S. We're using NH v2.2
<?xml version="1.0" encoding="utf-8"?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-lazy="false" assembly="MyEntities" namespace="Entities.Containers"> <class name="Container" table="[Container]" xmlns="urn:nhibernate-mapping-2.2">
<id name="Id" column="Id" type="Int32" unsaved-value="0">
<generator class="native" />
</id>
<property name="Capacity" column="Capacity">
<column name="Capacity" />
</property>
<property name="Description" column="Description" length="50" type="String">
<column name="Description" />
</property>
<loader query-ref="sqCurrentContainerAllocation"/> </class>
<sql-query name="sqCurrentContainerAllocation">
<return-scalar column="AllocatedItemsCount" type="int"></return-scalar>
SELECT COUNT(*) FROM [ContainerTracking]
WHERE [ContainerId] = :Id </sql-query>
</hibernate-mapping>
If you need to get some calculated property, you can use mapping with formula.
Let's extend your C# class:
public class Container
{
... // ID, Capacity, Description
public virtual int MyCount { get; set; }
And extend your mapping
<class name="Container" table="[Container]"
...
<property name="MyCount" insert="false" update="false" >
<formula>
(
SELECT count(*)
FROM [ContainerTracking] as ct
WHERE ct.[ContainerId] = Id
)
</formula>
</property>
the Id will be replaced with somethink like '_this.Id', the name of the column Id and its alias
This will of course load the count all the time (except projections) so think twice before use it
I need a HQL Query but I just dont get it.
SELECT * FROM Poll WHERE pid NOT IN (
SELECT pid FROM votes WHERE uid = 'theuserid')
I want all List of Poll´s back where the uid not in the table votes exists.
Also helpfull would be the hql query where the uid in the table votes exists, but I guess this is very similar ;-)
These are the 2 classes:
public class Poll {
private int pid;
private String name;
private String description;
private Date deadline;
private Set<Team> teams = new HashSet<Team>(0);
//some getter & setter
}
public class Vote {
private int vid;
private String uid;
private int pid;
private int tid;
private int votes;
//some getter & setter
}
Can smbdy please help me. I guess it is a join with a WHERE and NOT LIKE but I just dont get it.
Merci!
This is btw the hibernate mapping:
<hibernate-mapping>
<class name="package.model.Poll" table="poll">
<id name="pid" column="pid" >
<generator class="increment"/>
</id>
<property name="name" column="name" />
<property name="description" column="description" />
<property name="deadline" type="timestamp" column="deadline" />
<set name="teams" table="pollchoice"
inverse="false" lazy="false" fetch="select" cascade="all" >
<key>
<column name="pid" not-null="true" />
</key>
<many-to-many entity-name="knt.exceedvote.model.Team">
<column name="tid" not-null="true" />
</many-to-many>
</set>
</class>
</hibernate-mapping>
<hibernate-mapping>
<class name="package.model.Vote" table="votes">
<id name="vid" column="vid" >
<generator class="increment"/>
</id>
<property name="pid" column="pid" />
<property name="uid" column="uid" />
<property name="tid" column="tid" />
<property name="votes" column="votes" />
</class>
</hibernate-mapping>
Please keep in mind, Hibernate is designed using the notion of Object Graph, which is a name given to the relational objects.
That core concept is missing in your mapping (Poll and Vote seem to be isolated) hence I doubt you can use HQL in its current state.
In my opinion, you have two options:
Define the relationship between Poll, pid and Vote, uid. Then you should be able to write simple HQL.
Use native SQL through Hibernate session itself.
I would like to use "hilo" generator but there is no any complete example how to create "specific" table as NH documentation says, and which values pass to it.
The following code fragments taken from NH tutorial
public class Cat
{
private Int64 id;
private string name;
private char sex;
private float weight;
public Cat()
{}
public virtual Int64 Id
{
get { return id; }
set { id = value; }
}
....
}
Mapper
<hibernate-mapping ...>
<class name="Cat" table="Cat">
<id name="Id" >
<column name="CatId" sql-type="Int64" not-null="true"/>
<generator class="hilo"/>
</id>
<property name="Name">
<column name="Name" length="16" not-null="true" />
</property>
....
</class>
</hibernate-mapping>
DB table "Cat"
CatId bigint NOT NULL
Name varchar(16) NOT NULL
Sex char(1) NULL
Weight real NULL
doesn't create anything in the database by default.
Parameters in the "id" node
<param name="table">hi_value</param>
<param name="column">next_value</param>
<param name="max_lo">100</param>
gives "Invalid object name 'hi_value'" error message, without them I'm getting "Invalid object name 'hibernate_unique_key'."
Cuid.Comb that is shown in their tutorial works good but gives 99.12% of fragmentation when I added in a loop 20K cat objects.
Can somebody point me to an example of "hilo" implementation or give a tip what I'm missing?
Thanks.
This solution solved my problem. It's fairly simple, don't know why on nhibernate site there is no tiny example like that.
You may be running into NH-2687.
There is a table Item like,
code,name
01,parent1
02,parent2
0101,child11
0102,child12
0201,child21
0202,child22
Create a java object and hbm xml to map the table.The Item.parent is a Item whose code is equal to the first two characters of its code :
class Item{
String code;
String name;
Item parent;
List<Item> children;
.... setter/getter....
}
<hibernate-mapping>
<class name="Item" table="Item">
<id name="code" length="4" type="string">
<generator class="assigned" />
</id>
<property name="name" column="name" length="50" not-null="true" />
<many-to-one name="parent" class="Item" not-found="ignore">
<formula>
<![CDATA[
(select i.code,r.name from Item i where (case length(code) when 4 then i.code=SUBSTRING(code,1,2) else false end))
]]>
</formula>
</many-to-one>
<bag name="children"></bag>
</class>
</hibernate-mapping>
I try to use formula to define the many-to-one relationship,but it doesn't work!Is there something wrong?Or is there other method?
Thanks!
ps,I use mysql database.
add 2010/05/23
Pascal's answer is right,but the "false" value must be replaced with other expression,like "1=2".Because the "false" value would be considered to be a column of the table.
select i.code
from Item i
where (
case length(code)
when 4 then i.code=SUBSTRING(code,1,2)
else 1=2
end)
And I have another question about the children "bag" mapping.There isn't formula configuration option for "bag",but we can use "loader" to load a sql-query.I configure the "bag" as following.But it get a list whose size is 0.What's wrong with it?
<class>
... ...
<bag name="children">
<key />
<one-to-many class="Item"></one-to-many>
<loader query-ref="getChildren"></loader>
</bag>
</class>
<sql-query name="getChildren">
<load-collection alias="r" role="Item.children" />
<![CDATA[(select {r.*} from Item r join Item o where
o.code=:code and
(
case length(o.code)
when 2 then (length(r.code)=4 and SUBSTRING(r.code,1,2)=o.code)
else 1=2
end ))]]>
</sql-query>
According to the documentation, you're supposed to return the value of the computed foreign key, nothing more:
formula (optional): an SQL expression that defines the value for a computed foreign key.
So I would expect a query like this:
select i.code
from Item i
where (
case length(code)
when 4 then i.code=SUBSTRING(code,1,2)
else false
end)
Disclaimer: not tested.
I am customizing N2CMS's database structure, and met with an issue. The two classes are listed below.
public class Customer : ContentItem
{
public IList<License> Licenses { get; set; }
}
public class License : ContentItem
{
public Customer Customer { get; set; }
}
The nhibernate mapping are as follows.
<class name="N2.ContentItem,N2" table="n2item">
<cache usage="read-write" />
<id name="ID" column="ID" type="Int32" unsaved-value="0" access="property">
<generator class="native" />
</id>
<discriminator column="Type" type="String" />
</class>
<subclass name="My.Customer,My" extends="N2.ContentItem,N2" discriminator-value="Customer">
<join table="Customer">
<key column="ItemID" />
<bag name="Licenses" generic="true" inverse="true">
<key column="CustomerID" />
<one-to-many class="My.License,My"/>
</bag>
</join>
</subclass>
<subclass name="My.License,My" extends="N2.ContentItem,N2" discriminator-value="License">
<join table="License" fetch="select">
<key column="ItemID" />
<many-to-one name="Customer" column="CustomerID" class="My.Customer,My" not-null="false" />
</join>
</subclass>
Then, when get an instance of Customer, the customer.Licenses is always empty, but actually there are licenses in the database for the customer. When I check the nhibernate log file, I find that the SQL query is like:
SELECT licenses0_.CustomerID as CustomerID1_,
licenses0_.ID as ID1_,
licenses0_.ID as ID2_0_,
licenses0_1_.CustomerID as CustomerID7_0_,
FROM n2item licenses0_
inner join License licenses0_1_
on licenses0_.ID = licenses0_1_.ItemID
WHERE licenses0_.CustomerID = 12 /* #p0 */
It seems that nhibernate believes that the CustomerID is in the 'n2item' table. I don't know why, but to make it work, I think the SQL should be something like this.
SELECT licenses0_.ID as ID1_,
licenses0_.ID as ID2_0_,
licenses0_1_.CustomerID as CustomerID7_0_,
FROM n2item licenses0_
inner join License licenses0_1_
on licenses0_.ID = licenses0_1_.ItemID
WHERE licenses0_1_.CustomerID = 12 /* #p0 */
Could any one point out what's wrong with my mappings? And how can I get the correct licenses of one customer? Thanks in advance.
I'm not sure whether the SQL is incorrect, because the parent class mapping uses a discriminator so I'd expect all properties to be stored in the same table as the base class (n2item). However I'm not familiar with the "join table" syntax, I generally use joined-subclass so I might be misunderstanding.
Assuming the subclass mapping is correct, could the problem with the licenses be something to do with no Cascade setting being set for that collection?