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copied!<p>The Play CRUD controller doesn't work well with composite keys. Here's how you can work around it.</p> <p>First, decide on a stringified format for your composite keys - in the example below I've just taken the two keys (ssn, accountId) and concatenated them separated with a "-".</p> <p>In your model override the <code>_key</code> and <code>findById</code> methods from GenericModel and JPABase as follows:</p> <pre><code>package models; import play.db.jpa.GenericModel; import javax.persistence.Entity; import javax.persistence.Id; @Entity public class Part extends GenericModel { @Id public int ssn; @Id public int accountId; public String name; /** * Find a part by its composite id ("ssn-accountId") */ public static Part findById(String id) { // Split the composite id to extract ssn and accountId String[] elements = id.split("-"); int ssn = Integer.valueOf(elements[0]); int accountId = Integer.valueOf(elements[1]); return Part.find("ssn=? AND accountId=?", ssn, accountId).first(); } /** * Return a composite id ("ssn-accountId") */ public String _key() { return ssn + "-" + accountId; } } </code></pre> <p>Next override the <code>show</code> method in your controller:</p> <pre><code> package controllers; import models.Part; public class Parts extends CRUD { /** * CRUD show method doesn't know how to handle composite ids. * * @param id composite of ssn + "-" + accountId * @throws Exception */ public static void show(String id) throws Exception { // Do not rename 'type' or 'object' ObjectType type = ObjectType.get(getControllerClass()); notFoundIfNull(type); Part object = Part.findById(id); notFoundIfNull(object); render("CRUD/show.html", type, object); } } </code></pre> <p>That's it.</p>

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