One-to many relationship in EJB

hi forum
wish you a very happy and prosperous new year
i want to implement CMR in my project but to start with i tried sample application setting one-to many CMR between EMP and DEPT table of scott/tiger .the problem is i have to modify my orion-ejb-jar.xml how can we do it?

Are you using JDeveloper? JDeveloper automatically creates the orion-ejb-jar.xml file when you use the EJB wizard.

Similar Messages

One to many relationships in EJB

I have two EBs related by a one to many relationship. The first of these tables is called Student and has studentId as its key. The second of the tables has a composite key made up of studentID, courseID and semesterID.
However, when the tables are generated in NetBeans 5.5, I find that the Course table has studentID as both a primary key and a foreign key.
I am at a loss to understand this as I am new to NetBeans and EJB.
Can anyone advise?
Thanks
Martin O'Shea.
The Student class:
package CBSD_CW;
import java.io.Serializable;
import javax.persistence.*;
import java.util.*;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
public class Student_EB implements Serializable {
    // Table columns.
    @Id
    @Column(name = "STUDENT_ID", nullable = false)
    private Long studentId; // Student ID. Entity <Student><ID> from file: SampleData.xml.
    @Column(name = "FIRST_NAME", length = 50, nullable = true)
    private String firstName; // First Name. Entity <Student><FirstName> from file: SampleData.xml.
    @Column(name = "LAST_NAME", length = 50, nullable = true)
    private String lastName; // Last Name. Entity <Student><LastName> from file: SampleData.xml.
    @Column(name = "STUDENT_LEVEL", length = 2, nullable = true)
    private String studentLevel; // Student Level. Entity <Student><Level> from file: SampleData.xml.
    @Column(name = "PROGRAM_NAME", length = 50, nullable = true)
    private String programName; // Program Name. Entity <Student><ProgramName> from file: SampleData.xml.
    @Column(name = "PROGRAM_NUMBER", length = 3, nullable = true)
    private String programNumber; // Program Number. Entity <Student><ProgramNumber> from file: SampleData.xml.
    // 1:M relationship with Course_EB.
    @OneToMany(cascade=CascadeType.ALL, mappedBy="student")
    private List<Course_EB> courses;
    public List<Course_EB> getCourses() {
       return courses;
    public void setCourses(List<Course_EB> courses) {
       this.courses = courses;
    // Accessors and mutators.
    public Long getId() {
        return this.studentId;
    public void setId(Long studentId) {
        this.studentId = studentId;
    public String getFirstName() {
        return firstName;
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    public String getLastName() {
        return lastName;
    public void setLastName(String lastName) {
        this.lastName = lastName;
    public String getStudentLevel() {
        return studentLevel;
    public void setStudentLevel(String studentLevel) {
        this.studentLevel = studentLevel;
    public String getProgramName() {
        return programName;
    public void setProgramName(String programName) {
        this.programName = programName;
    public String getProgramNumber() {
        return programNumber;
    public void setProgramNumber(String programNumber) {
        this.programNumber = programNumber;
    // Other methods.
    public boolean equals(Object obj) {
       if (obj == this) {
           return (true);
       if (!(obj instanceof Student_EB)) {
           return (false);
       if (obj == null) {
           return (false);
       Student_EB student = (Student_EB) obj;
       return (student.studentId == studentId);
The Course class:
package CBSD_CW;
import javax.persistence.CascadeType;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToOne;
@Entity
public class Course_EB implements java.io.Serializable {
   Course_PK course;
   // M:1 relationship with Student_EB.
   private Student_EB student;
   @ManyToOne(cascade=CascadeType.ALL)
   @JoinTable(name = "Student_EB", joinColumns= @JoinColumn(name = "STUDENT_ID", referencedColumnName = "studentId"))
   public Student_EB getStudent() {
      return (student);
   public void setStudent(Student_EB student) {
      this.student = student;
   // Constructor.
   public Course_EB() {
   // Accessors and mutators.
   @EmbeddedId
   public Course_PK getCourse_PK () {
      return (course);
   public void setCourse_PK(Course_PK course) {
      this.course = course;
The Course_PK class:
package CBSD_CW;
import javax.persistence.Column;
import javax.persistence.Embeddable;
@Embeddable
public class Course_PK implements java.io.Serializable {
   // Table columns.
   @Column(name = "STUDENT_ID", length = 4, nullable = false)
   private long studentId; // Student ID. Entity <Student><ID> from file: SampleData.xml.
   @Column(name = "COURSE_ID", length = 4, nullable = false)
   private String courseId; // Course ID. Entity <Student><Course><Number> from file: SampleData.xml.
   @Column(name = "SEMESTER_CODE", length = 3, nullable = false)
   private String semesterCode; // Semester Code. Entity <Student><Course><SemesterCode> from file: SampleData.xml.
   @Column(name = "GRADE", nullable = true)
   private char grade; // Grade. Entity <Student><Course><Grade> from file: SampleData.xml.
   // Constructors.
   public Course_PK() {
   public Course_PK(long studentId, long courseid, String semesterCode) {
      this.studentId = studentId;
      this.courseId = courseId;
      this.semesterCode = semesterCode;
   // Accessors and mutators.
   public long getStudentId() {
      return (studentId);
   public void setStudentId(long studentId) {
      this.studentId = studentId;
   public String getCourseId() {
       return (courseId);
   public void setId(String courseId) {
       this.courseId = courseId;
   public String getSemesterCode() {
       return (semesterCode);
   public void setSemesterCode(String semesterCode) {
       this.semesterCode = semesterCode;
   public char getGrade() {
       return (grade);
   public void setGrade(char grade) {
       this.grade = grade;
   // Other methods.
   public boolean equals(Object obj) {
       if (obj == this) {
           return (true);
       if (!(obj instanceof Course_PK)) {
           return (false);
       if (obj == null) {
           return (false);
       Course_PK course = (Course_PK) obj;
       return ((course.studentId == studentId) &&
               (course.courseId.equals(courseId)) &&
               (course.semesterCode.equals(semesterCode)) &&
               (course.grade == grade));
}

Because you have field
@Column(name = "STUDENT_ID", length = 4, nullable = false)
   private long studentId; // Student ID. Entity <Student><ID> from file: SampleData.xml.In you Course_PK class. As a primary keys.
An again you are joining it in field
    @ManyToOne(cascade=CascadeType.ALL)
   @JoinTable(name = "Student_EB", joinColumns= @JoinColumn(name = "STUDENT_ID", referencedColumnName = "studentId"))So it is appearing both inPrimary Key and in Foreign Key.

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

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

One-to-many relationship within one bean

hello all,
Does S1 support a container managed one-to-many relationship to itself?
I used the verifer to verify my DD and the error is reported. (this prototype is migrated from weblogic6.1 and I use the S1 migration tool for the DD generation)
-----------------database schema-----------------
CREATE TABLE t_class_a
c_name VARCHAR2(255),
one_class_a_for_ma2918_id VARCHAR2(32), /* untruncated name: one_class_a_for_many_class_a_id */
object_id VARCHAR2(32) NOT NULL
CREATE UNIQUE INDEX t_class_a_id_PK ON t_class_a ( object_id );
ALTER TABLE t_class_a ADD ( CONSTRAINT t_class_a_id_PK PRIMARY KEY ( object_id ) USING INDEX );
ALTER TABLE t_class_a ADD ( CONSTRAINT FK_0 FOREIGN KEY ( one_class_a_for_ma2918_id ) REFERENCES t_class_a ( object_id ) );
---------------------------ejb-jar.xml------------------
<abstract-schema-name>ClassABean</abstract-schema-name>
<cmp-field>
<field-name>objectId</field-name></cmp-field>
<cmp-field>
<field-name>name</field-name></cmp-field>
<primkey-field>objectId</primkey-field>
<relationships>
<ejb-relation>
<ejb-relation-name>manyClassA_oneClassA</ejb-relation-name>
<ejb-relationship-role>
<description>optional</description>
<ejb-relationship-role-name>OneClassA-in-manyClassA_oneClassA</ejb-relationship-role-name>
<multiplicity>One</multiplicity>
<relationship-role-source>
<ejb-name>ClassAEJB</ejb-name></relationship-role-source>
<cmr-field>
<cmr-field-name>manyClassAsForOneClassA</cmr-field-name>
<cmr-field-type>java.util.Collection</cmr-field-type></cmr-field></ejb-relationship-role>
<ejb-relationship-role>
<description>optional</description>
<ejb-relationship-role-name>ManyClassA-in-manyClassA_oneClassA</ejb-relationship-role-name>
<multiplicity>Many</multiplicity>
<relationship-role-source>
<ejb-name>ClassAEJB</ejb-name></relationship-role-source>
<cmr-field>
<cmr-field-name>oneClassAForManyClassA</cmr-field-name>
</cmr-field>
</ejb-relationship-role>
</ejb-relation>
</relationships>
-----------sun-cmp-mapping.xml--------
<sun-cmp-mapping>
<schema>mySchema</schema>
<entity-mapping>
<ejb-name>ClassAEJB</ejb-name>
<table-name>T_CLASS_A</table-name>
<cmp-field-mapping>
<field-name>objectId</field-name>
<column-name>OBJECT_ID</column-name></cmp-field-mapping>
<cmp-field-mapping>
<field-name>name</field-name>
<column-name>C_NAME</column-name></cmp-field-mapping>
<cmr-field-mapping>
<cmr-field-name>manyClassAsForOneClassA</cmr-field-name>
<column-pair>
<column-name>T_CLASS_A.OBJECT_ID</column-name>
<column-name>T_CLASS_A.ONE_CLASS_A_FOR_MA2918_ID</column-name></column-pair></cmr-field-mapping></entity-mapping></sun-cmp-mapping></sun-cmp-mappings>
I beleive the migration tool missing the cmr-filed mapping for the oneClassAForManyClassA relation role.
but even if I add this mapping it still can't pass the verifiy.
So do I miss any thing or I can conclude S1 not support this one-to many self relation?
Any hint would be welcome.

It does.
There is a known problem with parsing self-referenced relationship info - the one side (with <multiplicity> Many) must be the first in the <ejb-relation> entry.
Regards,
Marina

One to many relationships

Hi I have a big problem :)
I want to use one to many relationships.
One yable with primary key, foreign key view_id. The second table on the many side with primary key view_id and another primary key.
The problem is that ejbc gives the followin error:
" [java] In relationship 'ViewType-SView', role 'ViewType-Has-SView', a weblogic-relationship-role element contains the wrong number of column mappings. A single column mapping must be given for each primary key column in the bean referenced by the mapping."
And that makes no sense for me. Any ideas?

weblogic-relationship-role element column mappings should be the same as defined in
<ejb-relationship-role>
<multiplicity></multiplicity>
</ejb-relationship-role>
Erno wrote:
Hi I have a big problem :)
I want to use one to many relationships.
One yable with primary key, foreign key view_id. The second table on the many side with primary key view_id and another primary key.
The problem is that ejbc gives the followin error:
" [java] In relationship 'ViewType-SView', role 'ViewType-Has-SView', a weblogic-relationship-role element contains the wrong number of column mappings. A single column mapping must be given for each primary key column in the bean referenced by the mapping."
And that makes no sense for me. Any ideas?

One to Many relationship in CMP

Hi,
How to create CMP entity bean that can map One To Many relationship?
Thanks.
(Actually, i have post this question in "Java programming" forum becoz i couldn't find the EJB link in forum main page...)

Hello Friend,
Go carefully through the RosterApp example in the J2EE tutorial.
It sure is going to help you.
See each and every tab and the values in the deployment tool.
Best of Luck

JPA one to many relationship and serialization

Hi,
I modeled a one to may relationship like this:
Parent Class WFData:
@OneToMany(mappedBy = "wfData", targetEntity = Positionen.class)
private Set<Positionen> positionen;
Child Class Positionen
@ManyToOne
@JoinColumn(name = "WF_REF_ID", referencedColumnName = "ID")
private WFData wfData;
Now I want to create an EJB session bean with a method which returns an object of type WFData (parent) published as web service . When I try to deploy the web service I get the following error message: Unable to generate serialization framework for web service
Does anyone know how to serialize a one-to-many relationship so I can use these objects in a web service?
Best regards,
Kevin

I found the solution to get serialization correctly working and enable the service to be used in Visual Composer.
You need to add the tag @XmlTransient to the getter method of the attribute in the child class that references the parent.
@XmlTransient
public WFData getWfData() {
return wfData;

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.

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.

Struggling with a one to many relationship in a sub-report

Post Author: Scott_tansley
CA Forum: General
I have a database schema as per below: tblENQUIRY tblDatasheets tblReportParasIRSID (PK) 1 --> & IRSID (FK) UID (PK)Attribute1 SHEETID (PK) 1 > & SHEETID (FK)Attribute2 Attribute1 LIST_ORDER tblStandardParasAttribute3 Attribute2 PARA_CODE (FK) & < 1 CODE (PK)etc... Attribute3 TEXT etc...
The PROBLEM I am a Crystal Reports Newbie, and having to work through things bit by bitu2026 I've managed to achieve quite a lot, but I'm totally stuck with this and would appreciate some help. I need to create a report (essentially a letter and some datasheets) around a one-to-many relationship, which I have managed to compile using a main report (for the one [tblENQUIRY]) and sub report (for the many [tblDatasheets]). Essentially I need a covering letter, then the u2018manyu2019 datasheets, and then a number of other pages (which are largely static text). I have created a main report which includes the covering letter, holds a subreport for the datasheets, and then contains the text for the additional pages. This all works fine, and I get the correct number of datasheets for each main report. My problem stems from the use of this sub report. This sub-report needs to hold some attribute values for each datasheet, which is fine. However, on each datasheet page I need to have some paragraphs, which are held in another one to many relationship. Each datasheet may have up to six paragraphs held as a code in tblReportParas, with a relationship to the text as held in tblStandardParas. My original thought would have been to embed another sub report, containing the values from tblStandardParas!TEXT, into the first sub report. However, I have found that it is not possible to have a sub-report inside another sub-report. I had seperated the first sub-report out from the main report, and then embedded another sub-report into it. This worked fine until I tried to stitch the sub-report back into the main report (at which point the sub-sub-report dissapeared from view). I have therefore reworked my sub-report a little, and the attribution is now stored in a pageheader, with the tblStandardParas!TEXT in a detail section below it. This almost works! The only problem is that there is no relationship between the pageheader and detail sections. To clarify, I would expect to have one datasheet, with the attribution at the top, and then the six paras below. Then, the same on the next page (assuming there is a second datasheet) for that report. Instead, I get the correct attribution, but the detail section actually gives every paragraph in the database, no matter which datasheet/or report it related to! I therefore need to limit the detail section to only show those paragraphs where the SHEETID in tblReportParas is the same as the tblDatasheets SHEETID. Any offers of advice would be appreciated.

Post Author: Scott_tansley
CA Forum: General
I managed to resolve this myself in the end. I moves the tblEnquiry data into report header/footer sections, this allowed me to add the tblDatasheets information into the details section, which gave me multiple pages - and then finally, the Paragraphs were added through the use of a sub report.
There's probably an even better way, but for now it works, it's quick - and so I'm going to go with it!
Thanks for your interest.

How do I create a One to many relationship page in Dreamweaver?

How do I create a page in dreamweaver that comes up after the user logs in from the log in page that will allow the user to:
Add, change and delete in 2 tables that are in my MYSQL database that is a one to many relationship
One thing that is confusing is how the foreign key that links to the one side of the relationship is created in the many side without the user inputting the foreign key each time adding information to the many side table.
I am creating this in Dreamweaver using a MYSQL database and PHP.

>Would the following be a part of it:
>
>Outer join
Probably not. When updating/inserting/deleting from 2 tables you perform each seperately. Table updates may join two or more tables to resolve the correct row(s) but you still only update one table at a time. Procedurally you would create a transaction, update the first table, update the second table and then commit the transaction.
EDIT: Well I take back my last comment. I see that MySQL does seem to support multiple table updates. I don't use MySQL so I can't really help you on that but the MySQL manual gives pretty clear syntax.

How to change the fetch size for a one-to-many relationship

With Toplink 10.1.3, since using scrollablecursor is a prerequisites for changing the fetchsize on a query (using the setFetchSize), I am wondering if it would be possible to change the fetchsize of the query which is associated to a one-to-many relationship.
So, is this possible? How ?

In TopLink 10.1.3 you can set the fetch-size on any query, it has nothing to do with using a ScrollableCursor.
Example:
readQuery.setFetchSize(100);
To set the fetch size on a mapping query use,
mapping.getSelectionQuery().setFetchSize(100);
In 10.1.3 you can only set this in code, not currently through XML or the Mapping Workbench. In 10.1.3.1 you should be able to set the value through XML as well.

Newbie: one to many relationship SQL error

Greetings all-
This is probably a slam dunk for you JDO experts. I'm a JDO newbie, working
with an existing schema in MySQL. I have a one to many relationship between
two tables:
Table "company":
Fields:
company_id: int(11) -- primary key
name : varchar(64)
division : varchar(64)
Table "company_products"
Fields:
company_id: int(11) -- foreign key to table company
product_name: varchar(64)
product_description: varchar(64)
So, I created the corresponding classes:
public class Company {
private int companyID;
private String company_name;
private String division;
// Array of CompanyProduct
private ArrayList companyProducts;
// .. methods omitted
public class CompanyProduct {
private int companyID;
private String productName;
private String productDesc;
// Methods omitted
Then I created the "package.jdo" file:
<?xml version="1.0"?>
<jdo>
<package name="com.packexpo.db">
<class name="Company">
<extension vendor-name="tt" key="table" value="company"/>
<extension vendor-name="tt" key="pk-column" value="company_id"/>
<extension vendor-name="tt" key="lock-column" value="none"/>
<extension vendor-name="tt" key="class-column" value="none"/>
<field name="companyID">
<extension vendor-name="tt" key="data-column" value="company_id"/>
</field>
<field name="name">
<extension vendor-name="tt" key="data-column" value="name"/>
<extension vendor-name="tt" key="column-length" value="64"/>
</field>
<field name="division">
<extension vendor-name="tt" key="data-column" value="division"/>
<extension vendor-name="tt" key="column-length" value="64"/>
</field>
<field name="companyProducts">
<collection element-type="com.packexpo.db.CompanyProduct"/>
<extension vendor-name="tt" key="inverse" value="companyID"/>
</field>
</class>
<class name="CompanyProduct">
<extension vendor-name="tt" key="table" value="company_product"/>
<extension vendor-name="tt" key="pk-column" value="company_id"/>
<extension vendor-name="tt" key="lock-column" value="none"/>
<extension vendor-name="tt" key="class-column" value="none"/>
<field name="companyID">
<extension vendor-name="tt" key="data-column" value="company_id"/>
</field>
<field name="productName">
<extension vendor-name="tt" key="data-column" value="product_name"/>
<extension vendor-name="tt" key="column-length" value="64"/>
</field>
<field name="productDesc">
<extension vendor-name="tt" key="data-column"
value="product_description"/>
<extension vendor-name="tt" key="column-length" value="64"/>
</field>
</class>
</package>
</jdo>
Enhancement works fine. I successfully query and retrive Company objects
from the database, but as soon as I try to get the list of CompanyProducts,
I get an SQL Error:
javax.jdo.JDODataStoreException: [SQL=SELECT company.COMPANYPRODUCTSX FROM
company WHERE company.company_id = 82061]
E0610 Error in executeQuery()
E0606 executeQuery() error --
E0701 Error in getResult().
E0708 Command results in error - 1054 Unknown column
'company.COMPANYPRODUCTSX' in 'field list'
NestedThrowables:
com.solarmetric.kodo.impl.jdbc.sql.SQLExceptionWrapper: [SQL=SELECT
company.COMPANYPRODUCTSX FROM company WHERE company.company_id = 82061]
E0610 Error in executeQuery()
E0606 executeQuery() error --
E0701 Error in getResult().
E0708 Command results in error - 1054 Unknown column
'company.COMPANYPRODUCTSX' in 'field list'
I know i have probably set up the package.jdo file incorrectly, but I'm at a
loss for what I did wrong.
Any suggestions?
Thanks!
-Mike

Hi,
915766 wrote:
I need to write sql for below requirement:
table structure is
serial no LPN
1 4
2 4
3 6
4 6
5 6
6 3
7 3
8 3
9 1
I have to pick distinct 'LPN' like below:That sounds like a job for "GROUP BY lpn".
(any serial no can be picked for the distinct LPN)It looks like you're displaying the lowest serial_no for each lpn. That's easy to do, using the aggregate MIN function.
results needs to be as below:
serial no LPN
1 4
3 6
6 3
9 1
Please suggest with sql.Here's one way:
SELECT    MIN (serial_no)   AS serial_no
,         lpn
FROM      table_x
GROUP BY lpn
ORDER BY lpn     -- if wanted
I hope this answers your question.
If not, post a little sample data (CREATE TABLE and INSERT statements, relevant columns only), and also post the results you want from that data.
Explain, using specific examples, how you get those results from that data.
Always say which version of Oracle you're using (e.g., 11.2.0.2.0).
See the forum FAQ {message:id=9360002}

Toplink one to many relationship

I am working on DAO layer for One to many relationship
how can we get the list child objects based on parent id..
we are using toplink ...

Hi,
If you are using with JPA, try this:
em.createQuery("select c from child c where c.parent.id = :id").setParameter("id", parentObject.getId())
.getResultList();

One-to many relationship in EJB

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