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PONHibernate Collection of collections fetching, Duplicate data
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  1. PONHibernate Collection of collections fetching, Duplicate data
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    copied!<p>I have a complex situation, where I need to map three different classes with NHibernate. Class1(Branch.cs) has a collection of Class2(Employee.cs) objects. At the same time Class2 also has a collection of Class3(Contacts.cs) objects. <br/> As data is very huge I used fetch keyword to retrieve data in single query. <br/> I used the query as<br/> <br/><b>Query1 - "from Branch b inner join fetch b.Employee e inner join fetch e.Contacts"</b> - Single query but duplicate results. <br/><b>Query2 - "from Branch b inner join fetch b.Employee"</b> - Multiple query, required results. <br/> <br/> I have used bags in mapping files. The query result seems to having duplicate results. How to remove duplicate results as well as retrieving data in single query. I am including mapping files as well as Classes.</p> <p><strong>Contacts.hbm.xml</strong></p> <pre><code> &lt;?xml version="1.0" encoding="utf-8"?&gt; &lt;hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="NHibernateSample" namespace="NHibernateSample"&gt; &lt;class name="Contacts" table="Contacts"&gt; &lt;id name="EmployeeID"/&gt; &lt;property name="EmployeeID"/&gt; &lt;property name="Mobile"/&gt; &lt;property name="Alternate"/&gt; &lt;/class&gt; &lt;/hibernate-mapping&gt; </code></pre> <p><strong>Branch.hbm.xml</strong></p> <pre><code> &lt;?xml version="1.0" encoding="utf-8"?&gt; &lt;hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="NHibernateSample" namespace="NHibernateSample"&gt; &lt;class name="Branch" table="Branch"&gt; &lt;id name="BranchCode"/&gt; &lt;property name="BranchCode"/&gt; &lt;property name="BranchName"/&gt; &lt;bag name="EmployeeList" cascade="all-delete-orphan" inverse="false" batch-size="10000"&gt; &lt;key column="BranchCode"/&gt; &lt;one-to-many class="Employee" /&gt; &lt;/bag&gt; &lt;/class&gt; &lt;/hibernate-mapping&gt; </code></pre> <p><strong>Employee.hbm.xml</strong></p> <pre><code> &lt;?xml version="1.0" encoding="utf-8"?&gt; &lt;hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="NHibernateSample" namespace="NHibernateSample"&gt; &lt;class name="Employee" table="Employee"&gt; &lt;id name="EmployeeId"/&gt; &lt;property name="EmployeeId"/&gt; &lt;property name="FirstName"/&gt; &lt;property name="LastName"/&gt; &lt;property name="BranchCode"/&gt; &lt;bag name="Contact" cascade="all-delete-orphan" inverse="false" batch-size="10000"&gt; &lt;key column="EmployeeID"/&gt; &lt;one-to-many class="Contacts" /&gt; &lt;/bag&gt; &lt;/class&gt; &lt;/hibernate-mapping&gt; </code></pre> <p><strong>Contacts.cs</strong></p> <pre><code>using System; using System.Collections.Generic; using System.Text; namespace NHibernateSample { public class Contacts { String employeeID; String mobile; String alternate; public Contacts() { } public virtual String EmployeeID { get { return employeeID; } set { employeeID = value; } } public virtual String Mobile { get { return mobile; } set { mobile = value; } } public virtual String Alternate { get { return alternate; } set { alternate = value; } } } } </code></pre> <p><strong>Employee.cs</strong></p> <pre><code> using System; using System.Collections.Generic; using System.Text; namespace NHibernateSample { public class Employee { String employeeId; String firstName; String lastName; String branchCode; List&lt;Contacts&gt; contact = new List&lt;Contacts&gt;(); public virtual List&lt;Contacts&gt; Contact { get { return contact; } set { contact = value; } } public virtual String EmployeeId { get { return employeeId; } set { employeeId = value; } } public virtual String FirstName { get { return firstName; } set { firstName = value; } } public virtual String LastName { get { return lastName; } set { lastName = value; } } public virtual String BranchCode { get { return branchCode; } set { branchCode = value; } } public Employee() { } } } </code></pre> <p><strong>Branch.cs</strong></p> <pre><code> using System.Collections.Generic; using System.Text; using System; namespace NHibernateSample { [Serializable] public class Branch { private String branchCode; private String branchName; private IList&lt;Employee&gt; employeeList = new List&lt;Employee&gt;(); public virtual IList&lt;Employee&gt; EmployeeList { get { return employeeList; } set { employeeList = value; } } public virtual String BranchCode { get { return branchCode; } set { branchCode = value; } } public virtual String BranchName { get { return branchName; } set { branchName = value; } } public Branch() { } } } </code></pre>
 

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