Zero to many relationship

Hi,
I have one RDBMS concept question.
if i have 2 tables with 0 to many realtionship. can i create referential integrity constraint between them?
In other words how can i tell whether the records in table A(child table) are not orphan records and have 0 to many relationship with table B(parent table) ?
Right not there is no constraint defined on both tables.
Thanks

974647 wrote:
Hi,
I have one RDBMS concept question.
if i have 2 tables with 0 to many realtionship. can i create referential integrity constraint between them?
In other words how can i tell whether the records in table A(child table) are not orphan records and have 0 to many relationship with table B(parent table) ?
Right not there is no constraint defined on both tables.
ThanksUmm, the parent would alsways be on the 0 side of the relationship. That is, a parent can have 0 or more chilldren, but a child must have one parent, no orphans allowed. The FK constraint would be something like:
alter table A add constraint a_fk
foreign key (a_column_from_a) references b (pk_column);John

Similar Messages

Many-to-many relationship - show all values

Hi,
I'm building a cube in 2008R2 and have a many-to-many relationship through a bridging table but when displaying the results it is effectively an inner join and I would like to see a full outer join with the unknown rows set to "unknown".
I've managed to achieve this by doing a full outer join in the view that creates my bridging table and having an unknown member in my dimensions but then when I added in a dimension that wasn't directly related to the bridging table the unknown rows
were removed again. I was able to get past this by adding a row to my fact table with all the keys set to unknown and the metrics set to zero.
Whilst this works it really does not seem like an ideal solution, especially as previously empty metrics are now returning a zero.
Is there any way to achieve this in SSAS? Perhaps in the way unknown members are processed?
Thanks,

cccparkhill,
What you did is the only way to achieve what you want.
In cubes you connect Dimensions throw Facts. By definition dimensions are
“How do business people describe the data that
results from the business process?”
and facts are “What are we measuring?”, noting the underlined
we can understand that _normally and usually_ the relation between the dimensions and the facts represent incidents happened in the real world ... the way you approach, think, and deal with dimensions and facts in cubes is different than dealing with tables
in normal relational transnational database.
Personally I do what you did when I want to achieve "Left join"
Please mark this reply as the answer
or vote as helpful, as appropriate, to make it useful for other readers

Many to Many Relationship using junction table..

Hello im testing a many to many relation ship on j2ee and found this issue.
Creating a relation ship table until now without succes to update the relationship table:
code fragment as is:
On application flow my session bean call the following method according with the specification i have no reason to call persist in my writer just on parent Object: Any clue on what is wrong ?
@TransactionAttribute(TransactionAttributeType.REQUIRED)
public void saveWriter (Book book , Writer writer){
try {
Book atBook = entityManager.merge(book);
Writer atWriter = entityManager.merge(writer);
book.getWriters().add(atWriter);
entityManager.persist(atBook);
entityManager.flush();
}catch (Exception ex)
ex.printStackTrace();
<entity class="com.octech.biblio.domain.Book" name="book">
<description></description>
<table name="books" />
<attributes>
<id name="id">
<generated-value strategy="IDENTITY"/>
</id>
<basic fetch="EAGER" name="bookName">
<column insertable="true" length="128" name="bookname" table="" updatable="true"/>
</basic>
<many-to-one name="Library" fetch="LAZY" target-entity="com.octech.biblio.domain.Library">
<join-table name="library_books">
<join-column name="books_id"/>
<inverse-join-column name="library_id"/>
</join-table>
<cascade/>
</many-to-one>
<many-to-many name="Writers" fetch="LAZY" target-entity="com.octech.biblio.domain.Writer">
<join-table name="writers_books">
<join-column name="books_id"/>
<inverse-join-column name="writer_id"/>
</join-table>
<cascade/>
</many-to-many>
</attributes>
</entity>
<entity class="com.octech.biblio.domain.Writer" name="writer">
<description></description>
<table name="writers" />
<attributes>
<id name="id">
<generated-value strategy="IDENTITY"/>
</id>
<basic fetch="EAGER" name="writerName">
<column insertable="true" length="128" name="writer_name" table="" updatable="true"/>
</basic>
<many-to-many name="Books" fetch="LAZY" target-entity="com.octech.biblio.domain.Book">
<join-table name="writers_books">
<join-column name="writer_id"/>
<inverse-join-column name="books_id"/>
</join-table>
<cascade/>
</many-to-many>
</attributes>
</entity>

sybrand_b wrote:
The way you write it yes, but there is one minor detail.
You can have a 0,1 or many relationship: one employee has zero, one or many phone numbers
but you can not have the opposite, as it doesn't make sense.
0, 1 or many phone numbers belong to 1 employee.
It is customary to use 0,1 or m when the relationship is optional.
Sybrand Bakker
Senior Oracle DBAIs this correct now ?
one to many : one employee has 0,1 or multiple phone numbers
many to one : 1 or multiple phone numbers to one employee

Many-to-many relationship performance problem

Hi:
I have model that uses a bridge table to solve a many-to-many relationship. Here it is:
dimension 1 -< fact table >-dimension 2-< bridge table >-additional data table
Now, when I drive from the additional data table with a specific value and join to the bridge table and dimension 2, the performance is fine. But, as soon as I add the fact table to the query, the query never returns. I'm in a development environment, so my fact table has 220K records, and the bridge table has 200K records. The dimension 2 and additional data tables have hundreds of records. In other words, it's not much data. I have indexes and referential constraints on all relevant columns.
Can anyone suggest what is happening to cause such a performance hit when I add the fact table to the query?
Thanks for any suggestions!

sybrand_b wrote:
The way you write it yes, but there is one minor detail.
You can have a 0,1 or many relationship: one employee has zero, one or many phone numbers
but you can not have the opposite, as it doesn't make sense.
0, 1 or many phone numbers belong to 1 employee.
It is customary to use 0,1 or m when the relationship is optional.
Sybrand Bakker
Senior Oracle DBAIs this correct now ?
one to many : one employee has 0,1 or multiple phone numbers
many to one : 1 or multiple phone numbers to one employee

SELECT on One to many Relationship

Hi am trying to run a select statement on one to many relationship.
TableA is the main table with acount number and Total_Payments
TableB,TableC and TableD have a lot of account number and payments
per day
Note an account might on TableA might not be on TableB or TableC since it was not paid for that day hence 'if it is Null i'll like to populate a zero.
OUTPUT should be :
TableA.Account_No | Total_Amount(amounts from TableB/C/D)
Regards.

Hello,
Please refer to the following statements. If I have any misunderstand, please post the DDL of the tables and sample data for further analysis:
SELECT A.account, SUM(ISNULL(B.payment,0)+ISNULL(C.payment,0)+ISNULL(D.payment,0)) As Total_Amounts
FROM TableA A LEFT JOIN TableB B ON A.account=B.account
LEFT JOIN TableC C ON A.account=C.account
LEFT JOIN TableD D ON A.account=D.account
GROUP BY A.Account
Regards,
Fanny Liu
If you have any feedback on our support, please click here.
Fanny Liu
TechNet Community Support

Problem with 1-to-many relationship between entity beans

Hi All!
I have two tables TMP_GROUP and TMP_EMPLOYEE with following fields:
TMP_GROUP: ID, CAPTION, COMMENT, STATUS.
TMP_EMPLOYEE: ID, LOGIN, GROUP_ID.
For this tables i create two entity beans GROUP and EMPLOYEE respectively.
The relationship looks like this
descriptor ejb.xml:
<ejb-relation>
            <description>description</description>
            <ejb-relation-name>employeesOfGroup</ejb-relation-name>
            <ejb-relationship-role>
                <ejb-relationship-role-name>com.mypackage.GroupBean</ejb-relationship-role-name>
                <multiplicity>One</multiplicity>
                <relationship-role-source>
                    <ejb-name>GroupBean</ejb-name>
                </relationship-role-source>
                <cmr-field>
                    <cmr-field-name>employees</cmr-field-name>
                    <cmr-field-type>java.util.Collection</cmr-field-type>
                </cmr-field>
            </ejb-relationship-role>
            <ejb-relationship-role>
                <ejb-relationship-role-name>com.mypackage.EmployeeBean</ejb-relationship-role-name>
                <multiplicity>Many</multiplicity>
                <relationship-role-source>
                    <ejb-name>EmployeeBean</ejb-name>
                </relationship-role-source>
            </ejb-relationship-role>
        </ejb-relation>
descriptor persistent.xml:
<table-relation>
               <table-relationship-role
                    key-type="PrimaryKey">
                    <ejb-name>GroupBean</ejb-name>
                    <cmr-field>employees</cmr-field>
               </table-relationship-role>
               <table-relationship-role
                    key-type="NoKey">
                    <ejb-name>EmployeeBean</ejb-name>
                    <fk-column>
                         <column-name>GROUP_ID</column-name>
                         <pk-field-name>ejb_pk</pk-field-name>
                    </fk-column>
               </table-relationship-role>
          </table-relation>
Now i implement business method:
public Long addEmployee(String login, long groupId) {
          Long result;
          try {
               EmployeeLocal employee = employeeHome.create(login);
               GroupLocal group =
                    groupHome.findByPrimaryKey(new Long(groupId));
               Collection employees = group.getEmployees();
               employees.add(employee);
               result = (Long) employee.getPrimaryKey();
          } catch (CreateException ex) {
               result = new Long(0);
          } catch (FinderException ex) {
               result = new Long(0);
          return result;
When i call this method from web service, the following exception is raised:
com.sap.engine.services.ejb.exceptions.BaseTransactionRolledbackLocalException: Exception in method com.mypackage.GroupLocalHomeImpl0.findByPrimaryKey(java.lang.Object).
P.S.
1) I have transaction attribute set to "Required" for all methods of all beans
2) I have unique index for each table:
TMP_GROUP_I1: CAPTION
TMP_EMPLOYEE_I1: LOGIN (however i think GROUP_ID must be added here too)
3) I tried many:many relationship with this tables and it works fine
4) I try another implementation of addEmployee method with
EmployeeLocal employee = employeeHome.create(login, groupId);
without using GroupLocal cmr-field and GroupLocalHome findByPrimaryKey method, the result is same error.
Can somebody help me with this problem?
Thanks in advance.
Best regards, Abramov Andrey.

gimbal2 wrote:
1: The @JoinColumn on the listOfDepartments collection in Company is wrong. It should be something like this for a bidirectional relationship:
@OneToMany(mappedBy="company") // company is the matching property name in Department
private List <Department> listOfDepartment = new ArrayList<Department>();Note that I removed the fetch configuration; onetomany is fetched lazy by design. Saves some clutter eh.
2: use a Set in stead of a List (hibernate doesn't like lists much in entities and will break when you create slightly more complex entity relations)
3: don't just slap cascades on collections, especially of type ALL. Do it with care. In the many years I've been using JPA I've only had to cascade deletes in very specific situations, maybe once or twice. I never needed any of the other cascade types, they just invite sloppy code if you ask me. When working with persistence you should apply a little precision.I made all changes as you mentioned but still compID in department table shows null value...

Problem with 1:many relationship between entity beans.

Hi All!
I have two tables TMP_GROUP and TMP_EMPLOYEE with following fields:
TMP_GROUP: ID, CAPTION, COMMENT, STATUS.
TMP_EMPLOYEE: ID, LOGIN, GROUP_ID.
For this tables i create two entity beans GROUP and EMPLOYEE respectively.
The relationship looks like this
descriptor ejb.xml:
<ejb-relation>
            <description>description</description>
            <ejb-relation-name>employeesOfGroup</ejb-relation-name>
            <ejb-relationship-role>
                <ejb-relationship-role-name>com.mypackage.GroupBean</ejb-relationship-role-name>
                <multiplicity>One</multiplicity>
                <relationship-role-source>
                    <ejb-name>GroupBean</ejb-name>
                </relationship-role-source>
                <cmr-field>
                    <cmr-field-name>employees</cmr-field-name>
                    <cmr-field-type>java.util.Collection</cmr-field-type>
                </cmr-field>
            </ejb-relationship-role>
            <ejb-relationship-role>
                <ejb-relationship-role-name>com.mypackage.EmployeeBean</ejb-relationship-role-name>
                <multiplicity>Many</multiplicity>
                <relationship-role-source>
                    <ejb-name>EmployeeBean</ejb-name>
                </relationship-role-source>
            </ejb-relationship-role>
        </ejb-relation>
descriptor persistent.xml:
<table-relation>
               <table-relationship-role
                    key-type="PrimaryKey">
                    <ejb-name>GroupBean</ejb-name>
                    <cmr-field>employees</cmr-field>
               </table-relationship-role>
               <table-relationship-role
                    key-type="NoKey">
                    <ejb-name>EmployeeBean</ejb-name>
                    <fk-column>
                         <column-name>GROUP_ID</column-name>
                         <pk-field-name>ejb_pk</pk-field-name>
                    </fk-column>
               </table-relationship-role>
          </table-relation>
Now i implement business method:
public Long addEmployee(String login, long groupId) {
          Long result;
          try {
               EmployeeLocal employee = employeeHome.create(login);
               GroupLocal group =
                    groupHome.findByPrimaryKey(new Long(groupId));
               Collection employees = group.getEmployees();
               employees.add(employee);
               result = (Long) employee.getPrimaryKey();
          } catch (CreateException ex) {
               result = new Long(0);
          } catch (FinderException ex) {
               result = new Long(0);
          return result;
When i call this method from web service, the following exception is raised:
com.sap.engine.services.ejb.exceptions.BaseTransactionRolledbackLocalException: Exception in method com.mypackage.GroupLocalHomeImpl0.findByPrimaryKey(java.lang.Object).
P.S.
1) I have transaction attribute set to "Required" for all methods of all beans
2) I have unique index for each table:
TMP_GROUP_I1: CAPTION
TMP_EMPLOYEE_I1: LOGIN (however i think GROUP_ID must be added here too)
3) I tried many:many relationship with this tables and it works fine
4) I try another implementation of addEmployee method with
EmployeeLocal employee = employeeHome.create(login, groupId);
without using GroupLocal cmr-field and GroupLocalHome findByPrimaryKey method, the result is same error.
Can somebody help me with this problem?
Thanks in advance.
Best regards, Abramov Andrey.

I have posted excerpts from my orion-ejb-jar.xml file in this posting: Problem mapping a 1:M relationship between two entity EJBs w/ a compound PK
Sorry for the duplicate postings, but I was getting errors on the submission.
April

ONE-to-MANY relationship between tables and forms in APEX

I recently started using APEX and I have run into an issue.
I have a ONE-TO-MANY relationship between two tables, A1 and A2, respectively.
A1:
A1_ID
Item
A2:
A2_ID
SubItem
A1_ID
I have 2 forms (lets call it F1 and F2) that I use to capture data for A1 and A2.
On F2, I have the following fields that are setup to capture data:
A2.A1_ID
**A1.Item (this is a drop down that is populated using a SELECT statement where the select uses A1.Item field)
A2.SubItem (user would enter SubItem)
Note: A2.A2_ID is populated using a SEQ
Everytime I pick **A1.Item on F2, is there a way to link to A1 table and display A1.A1_ID for every **A1.Item selected on F2?
If so, I want to store the value captured in F2 for the A1_ID field into A2 table to maintain my 1-to-MANY relationship.
If this will work, how do I go about implementing this solution?
Can someone help me?

I think it sounds like you are asking for a Master-Detail form. Try that and see what you get.
chris.

Many to Many Relationships in ejb.....Urgent Pls help

hi all,
Am working in EJB.Now we are coding for many to many relationship.
Company and Salary register
One Company can have many salary register and More than one company can have one salary register
Companyand Salary register are the two tables having details of it.And the intermediate table having pk of company and salary register is Company_salary_register table,I want to add the value in this table having seperate interface.
How to model it? I have given the add method of this company_salary_register table in company bean.I am getting the value of this one as collection.But it is asking me to add the values as the instance of LocalSalary(interfaceand entitybean).If i type cast it as Local Salary Class castexception occurs
Please help me.Even Material of Modelling Many to Many relationship in EJB is enough.
thanx in advance,

THaaaaaanks alottt for the quick reply...
I used the first way to insert the document and i was successful...
but thing is that..
when i do
SQL>desc message_type
message_type is NOT FINAL
Name Null? Type
SYS_XDBPD$ XDB.XDB$RAW_LIST_T
to VARCHAR2(4000 CHAR)
from VARCHAR2(4000 CHAR)
subject VARCHAR2(4000 CHAR)
body VARCHAR2(4000 CHAR)
i can see the structure...
and when i
select count(*) from messages
it says count is 1.
so how to know where the data is ..like below in the data :
'to' it has '[email protected]'
and for 'from' it has '[email protected]'..and so on..
<message>
<to>[email protected]</to>
<from>[email protected]</from>
<subject>Question</subject>
<body>Does this demo work?</body>
</message>
so what is the command to get that data...
because when i do
select * from message_type..it says
select * from message_type
ERROR at line 1:
ORA-04044: procedure, function, package, or type is not allowed here
Plss help me outt.......this will be my final step...
Thankssssssssssssssss

Urgent : java bean having bidirectional one to many relationship

Hi,
We have complex requirement in our application.
We need to copy java bean having bidirectional one to many relationship to another javabean having bidirectional one to many relationship..
E.g
Class Basket1 {
public String color;
pubic String type;
public List<Basket1> basketList = new ArrayList()
Class Basket2 {
public String color;
pubic String type;
public List<Basket2> basketList = new ArrayList()
We need to exact copy Basket1 to Basket2. We are in trouble to copy List of child because we do not have how many child Basket1 have of same type..
Can someone help us how we can implement such kind of complex object bidirectional one to many relationship??

I can't see anything bidirectional about these relationships. What I can see is a couple of BasketN classes that look identical so I don't know why they both exist, and they both contain lists of themselves as members, which suggests some kind of tree structure. Nothing bidirectional there. I can see tat these things can form circular object graphs but I don't see why you would want to do that.
We need to exact copy Basket1 to Basket2And I don't know what that means. Please explain.

Creating data in a many-to-many-relationship

Hello,
we really have problems in implementing a JClient dialog based on BC4J for creating data in a many to many relationship - especially with cascade delete on both sides.
Simplified our tables look like:
create table A_TABLE
A_ID VARCHAR2(5) not null,
A_NAME VARCHAR2(30) not null,
constraint PK_A_TABLE primary key (A_ID),
constraint UK_A_TABLE unique (A_NAME)
create table B_TABLE
B_ID VARCHAR2(5) not null,
B_NAME VARCHAR2(30) not null,
constraint PK_B_TABLE primary key (B_ID),
constraint UK_B_TABLE unique (B_NAME)
create table AB_TABLE
A_ID VARCHAR2(5) not null,
B_ID VARCHAR2(5) not null,
constraint PK_AB_TABLE primary key (A_ID, B_ID),
constraint FK_AB_A foreign key (A_ID) references A_TABLE (A_ID) on delete cascade,
constraint FK_AB_B foreign key (B_ID) references B_TABLE (B_ID) on delete cascade
Could JDev Team please provide a BC4J/JClient sample that performs the following task:
The dialog should use A_TABLE as master and AB_TABLE as detail. The detail displays the names associated with the IDs. Next to AB_TABLE should be a view of B_TABLE which only displays rows that are currently not in AB_TABLE. Two buttons are used for adding and removing rows in AB_TABLE. After adding or removing rows in the intersection the B_TABLE view should be updated. The whole thing should work in the middle and client tier. This means no database round trips after each add/remove, no posts for AB_TABLE and no query reexecution for B_TABLE until commit/rollback.
This is a very common szenario: For an item group (A_TABLE) one can select and deselect items (AB_TABLE) from a list of available items (B_TABLE). Most of JDeveloper4s wizards use this. They can handle multi/single selections, selections from complex structures like trees and so on. Ok, the wizards are not based on BC4J - or? How can we do it with BC4J?
Our main problems are:
1. Updating the view of B_TABLE after add/remove reflecting the current selection
2. A good strategy for displaying the names instead of the IDs (subqueries or joining the three tables)
3. A JBO-27101 DeadEntityAccessException when removing an existing row from AB_TABLE and adding it again
Other problems:
4. We get a JBO-25030 InvalidOwnerException when creating a row in AB_TABLE. This is caused by the composition. We workaround this using createAndInitRow(AttributeList) on the view object (instead of create()). This is our add-Action:
ViewObject abVO = panelBinding.getApplicationModule().findViewObject("ABView");
ViewObject bVO = panelBinding.getApplicationModule().findViewObject("BView");
Row bRow = bVO.getCurrentRow();
NameValuePairs attribList = new NameValuePairs(
new String[]{"BId"}, new Object[]{bRow.getAttribute("BId")});
Row newRow = abVO.createAndInitRow(attribList);
abVO.insertRow(newRow);
5. After inserting the new row the NavigationBar has enabled commit/rollback buttons and AB_TABLE displays the row. But performing a commit does nothing. With the following statement after insertRow(newRow) the new row is created in the database:
newRow.setAttribute("BId", bRow.getAttribute("BId"));
Please give us some help on this subject.
Best regards
Michael Thal

<Another attempt to post a reply. >
Could JDev Team please provide a BC4J/JClient sample
that performs the following task:
The dialog should use A_TABLE as master and AB_TABLE
as detail. The detail displays the names associated
with the IDs. Next to AB_TABLE should be a view of
B_TABLE which only displays rows that are currently
not in AB_TABLE. Two buttons are used for adding and
removing rows in AB_TABLE. After adding or removing
rows in the intersection the B_TABLE view should be
updated. The whole thing should work in the middle
and client tier. This means no database round trips
after each add/remove, no posts for AB_TABLE and no
query reexecution for B_TABLE until commit/rollback.
This is a very common szenario: For an item group
(A_TABLE) one can select and deselect items
(AB_TABLE) from a list of available items (B_TABLE).
Most of JDeveloper4s wizards use this. They can
handle multi/single selections, selections from
complex structures like trees and so on. Ok, the
wizards are not based on BC4J - or? How can we do it
with BC4J?
Our main problems are:
1. Updating the view of B_TABLE after add/remove
reflecting the current selectionYou should be able to use insertRow() to insert the row into proper collection.
However to remove a row only from the collection, you need to add a method on the VO subclasses (and perhaps export this method so that the client side should see it) to unlink a row from a collection (but not remove the associated entities from the cache).
This new method should use ViewRowSetImpl.removeRowAt() method to remove the row entry at the given index from it's collection. Note that this is an absolute index and not a range index in the collection.
2. A good strategy for displaying the names instead
of the IDs (subqueries or joining the three tables)You should join the three tables by using reference (and perhaps readonly) entities.
3. A JBO-27101 DeadEntityAccessException when
removing an existing row from AB_TABLE and adding it
againThis is happening due to remove() method on the Row which is marking the row as removed. Attempts to add this row into another collection will throw a DeadEntityAccessException.
You may 'remove the row from it's collection, then call 'Row.refresh' on it to revert the entity back to undeleted state.
>
Other problems:
4. We get a JBO-25030 InvalidOwnerException when
creating a row in AB_TABLE. This is caused by the
composition. We workaround this using
createAndInitRow(AttributeList) on the view object
(instead of create()). This is our add-Action:
ViewObject abVO =
O =
panelBinding.getApplicationModule().findViewObject("AB
iew");
ViewObject bVO =
O =
panelBinding.getApplicationModule().findViewObject("BV
ew");
Row bRow = bVO.getCurrentRow();
NameValuePairs attribList = new NameValuePairs(
new String[]{"BId"}, new
String[]{"BId"}, new
Object[]{bRow.getAttribute("BId")});
Row newRow = abVO.createAndInitRow(attribList);
abVO.insertRow(newRow);This is a handy approach. Note that Bc4j framework does not support dual composition where the same detail can be owned by two or more masters. In those cases, you also need to implement post ordering to post the masters before the detail (and reverse ordering for deletes).
>
5. After inserting the new row the NavigationBar has
enabled commit/rollback buttons and AB_TABLE displays
the row. But performing a commit does nothing. With
the following statement after insertRow(newRow) the
new row is created in the database:
newRow.setAttribute("BId",
d", bRow.getAttribute("BId"));This bug in JDev 903 was fixed and a patch set (9.0.3.1) is (I believe) available now via MetaLink.
>
>
Please give us some help on this subject.
Best regards
Michael Thal

How to insert data in a one-to-many relationship

How do you insert data into the client, my model entity beans have a one-to-many relationship.
PARENT ENTITY BEAN
PARENT-ID
PARENT-NAME
The ejbCreate(Integer parentID,String name)
CHILD ENTITY BEAN
CHILD-ID
CHILD-NAME
PARENT-ID(foreign key of PARENTID).
ejbCreate(Integer parentID,String name,String foreignparentID)
In a jsp page i collect the parent details and 3 corresponding chld details in a text box.
Can you please tell me how do i proceed from here...
ie. how to i insert data into the entity beans..
Do i pass the child as a collection, and within parents ejbCreate() method do i lookup for the childs home interface and insert one -by -one from the collection.
1. Considering the above example, can some one pls tell how the ejbCreate() mehod signatures, for the parent and child entity beans should be.
2. Pls also show some sample client code as to how to make an insertion.
3. In case you are passing a collection of child data, then in what format does one have to insert into a collection and also how does the container know how to insert the values in the child table , bcoz we are passing as a collection.
4.In case collections cannot be inserted do we need to iterate into the collection in parent's ejbCreate() method, and manually insert into the database of the childtable, thereby creating child entity beans.
Thanks for your time and support...
regards
kartik

Hi,
3. In this case of course child's ejbCreate(and postCreate) looks like
ejbCreate(Integer childID,String name,ParentLocal parent) {
setId(Id);
setName(name);
ejbPostCreate(Integer childID,String name,ParentLocal parent) {
setParent(parent);
Here you don't need IDs, but it happens only using Locals, not Remotes, if I'm not wrong. Container does it itself.
1. Of course, if you have parent.getChildren() and parent.setChildren() then you don't need any loops, but it should be done anyway in postCreate, because in ejbCreate there no parent exists yet.
Once more 3: example - I'm using JBoss 3.2.5 as EJB container. It has tomcat inside and EJB and JSP+Struts use the same jvm. It means for me that I don't need to use remote interfaces, just locals. And in this case I can implement ejb-relations. So, a have the abstract method parent.getChildren() which returns Collection of ChildLocal - s and method parent.setChildren(Collection childrenLocals) which creates/modifies children by itself.
I have not used remotes for a long time, but as I remember it was not possible to implement ejb-relations using remotes.
regards,
Gio

Many to Many Relationship

In powerpivot we are facing problem in resolving the many-to-many relationship between tables.
Current table schema is:
Having 4 tables-
Bills - columns are- Bill No(primary key)
Billing Fee Table-Fee ID(primary key), Bill Type, Sub Bill Type
FeeList Table-FeeList ID(primary key),Fee ID(Foriegn Key to Billingble),
Bill No(Foriegn Key to Bills)
Payments Table-Pay ID(Primary Key), Bill No(Foriegn Key to Bills)
Bills is the primary table for Feelist Table
and Payments Table -Bill No is the primary key.
Billing Fee Table is primary table for FeeList Table -
Fee ID is the primary key.
To create a pivot table using Payments Table, I need
Bill Type and Sub Bill Type. Hence fetched from
Biling Fee Table to FeeList Table based on the
Fee ID column using RELATED function.
As FeeList Table and Payments Table is having duplicate
Bill Nos, it is not possible to get Bill Type and
Sub Bill Type to Payments Table. I am trying to use LOOKUPVALUE
function to get data based on the Bill No, as there is no direct relationship exists between these two tables.
I have tried using
=LOOKUPVALUE('FeeList Table'[Sub Bill Type], 'FeeList Table'[Bill No], 'Payments Table'[Bill No]) function. But
the lookupvalue function returns an error if a duplicate is found.
Error is as below:
Calculation error in column 'Payments Table'[Sub Bill Type]: A table of multiple values was supplied where a single value was expected.
Kindly assist to resolve this issue.
Thanks

Hi Rekha,
What should your LOOKUPVALUE return if multiple rows are found in the FeeListTable? By the way it should work if a really finds "duplicates" (i.e. multiple times the same return value) but fails if it returns multiple rows with different values.
If you for example would want to return the first entry that was found, you could try (have not checked in PP for typos):
CALCULATE(MIN('FeeList Table'[Sub Bill Type]),
FILTER('FeeList Table',
'FeeList Table'[Bill No] = 'Payments Table'[Bill No]
Edit: a very nice way to handle Many-to-Many relationships is explained here:
http://blog.gbrueckl.at/2012/05/resolving-many-to-many-relationships-leveraging-dax-cross-table-filtering/
Julian Wissel | BI for NAV @ http://en.navbi.com | Blog @ blog.navida.eu

Many to many relationship mapping.

Hi
I have a basic question on how to create a good java class model (POJOs) based on the database model.
I Have to follwing tables
Table1 with columns as
ID1
name
description
Table2 with columns as
ID2
dateCreated ..etc.
Since there is a many to many relationship between table1 and table2
So to map that we have a table3 with columns
ID3
ID1 // fk table1
ID2 // fk table2
browserName
startTime
endTime
So when I create Java classes:
// corresponding to table 1
Class MyTable1
private Integer ID1;
private List ID2; // to map with the table2
// corresponding to table 2
Class MyTable2
private Integer ID2
private List ID1; // to map with table 1
In this way I can create my classes. Is this the best way to put it together.
And where to put the attributed specific to table3. Like the BrowserName and the StartTime and the EndTime.
Any suggestion please.
Thanks.

Your names leave a lot to be desired. Let's start with an example. Suppose I have a problem involving employees and the tasks assigned to them. An employee may have any number of tasks assigned to them and a task can be assigned to any number of employees. The assignment itself has more attributes: when it was assigned, its priority and so on.
public interface Employee {
    Long getId(); //etc...
    Set<Assignment> getAssignments();
    void setAssignments(Set<Assignment> assignments);
public interface Task {
    Long getId(); //etc...
    Set<Assignment> getAssignments();
    void setAssignments(Set<Assignment> assignments);
public interface Assignment {
    Long getId(); //etc...
    Employee getEmployee();
    void setEmployee(Employee employee);
    Task getTask();
    void setTask(Task task);
}This assumes you want to navigate in all directions: from an employee to their assignments, from a task to its assignments and from an assignment to it employee and task.

Many to many relationship does not work on certain role played dimension

Hi,
I have a cube with role playing Account dimension, used once as “Account” and once as “Other Account” dimension.
I’ve added Trip dimension related to the account dimension by a bridge table AccountTrip
making a many to many relationship (many accounts can be in one trip and one account can go to many trips).
When I added the bridge measure group to the cube, I saw in the dimension usage tab that the relationship between the bridge and the Account dimension was done automatically.
I added the trip dimension with regular relationship to the bridge measure group and many to many relationship to the main fact table using the bridge group.
All compiled fine and gave correct results. Then I noticed that when slicing the fact table by the Other account dimension I get correct results,
but when I add the Trip dimension I get the results as if I was slicing by the Account dimension, not by the “Other account” dimension.
I checked the cube and noticed I did not set the relationship between the bridge to the “Other Account” dimension (role playing). I set it now (regular relationship, same as the account dimension), but still getting the same results.
Conclusion- when slicing by the new Trip (M2M) dimension and the “Other Account”
(role played) dimension I get the results of the “Account” dimension, not those of the “Other Account” dimension.
I checked the relationships of the “Other Account” dimension in the cube but it looks correctly set (to the external account of the main fact table and to account of the bridge table).
(Just to note I have two other bridges on the cube which are not related and don’t look like they need to be related, plus two other measure groups of the main fact table used for distinct count which are related appropriately).
What else should be done???
I would greatly appreciate your help!
Thanks
Namnami

The update server is down; try this temporary workaround
App Store>Purchased>Select "All"
Note: Look out for apps that have the word "Update"
http://i1224.photobucket.com/albums/ee374/Diavonex/9c256282736869f322d4b3071bbb2 a82_zps51a6f546.jpg

Zero to many relationship

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