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POjpa set where-clause in query for fields over 2 mapjoins
 

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    <p>I'm trying to construct a complex query. My entities look as follows:</p> <pre><code>@Entity public class Configuration{ @Id @Column(name="CONF_ID") protected Long configurationId; @ManyToMany @MapKey(name="componentType") @JoinTable(name="CONF_COMP", joinColumns={@JoinColumn(name="CONF_ID", referencedColumnName="CONF_ID")}, inverseJoinColumns={@JoinColumn(name="COMP_ID", referencedColumnName="componentId")}) protected Map&lt;String, Component&gt; components; } </code></pre> <p>And </p> <pre><code>@Entity public class Component { @Id protected long componentId; @ElementCollection protected Map&lt;String, String&gt; properties; @ManyToMany(mappedBy="components") private List&lt;Configuration&gt; configurations; @Column(name="COMP_TYPE") protected String componentType; } </code></pre> <p>My problem lies in querying the <code>properties</code> field properly. I can't seem to create a query to get all Configurations where Component A has Property Prop1 = 1 and Component B has Property Prop2=2. I tried the following without success.</p> <pre><code>Root&lt;Configuration&gt; conf = cq.from(Configuration.class); MapJoin&lt;Configuration, String, Component&gt; compJoin = conf.join(Configuration_.components, JoinType.LEFT); MapJoin&lt;Component, String, String&gt; propJoin = compJoin.join(Component_.properties, JoinType.LEFT); Predicate p1 = cb.and( cb.equal(mapJoin.key(), "A"), cb.equal(propJoin.key(), "Prop1"), cb.equal(propJoin.value(), "1")); Predicate p2 = cb.and( cb.equal(mapJoin.key(), "B"), cb.equal(propJoin.key(), "Prop2"), cb.equal(propJoin.value(), "2")); Predicate[] pArray = new Predicate[]{p1, p2}; cq.where(pArray); cq.select(conf).distinct(true); </code></pre> <p>EDIT: The query, as outputted by the logger, looks like this:</p> <pre><code>SELECT DISTINCT t2.CONF_ID, t2.DTYPE, t2.TOTALPRICE, t2.NAME FROM CONFIGURATION t2 LEFT OUTER JOIN (CONF_COMP t3 JOIN COMPONENT t1 ON (t1.COMPONENTID = t3.COMP_ID)) ON (t3.CONF_ID = t2.CONF_ID) LEFT OUTER JOIN Component_PROPERTIES t0 ON (t0.Component_COMPONENTID = t1.COMPONENTID) WHERE (((((t1.COMP_TYPE = ?) AND (t0.PROPERTIES_KEY = ?)) AND t0.PROPERTIES LIKE ?) AND (((t1.COMP_TYPE = ?) AND (t0.PROPERTIES_KEY = ?)) AND t0.PROPERTIES LIKE ?)) AND (t2.DTYPE = ?)) bind =&gt; [7 parameters bound] </code></pre> <p>I'm guessing it is trying to find a Configuration where all the conditions apply to the SAME component maybe? It works if I apply restrictions on only one Component, but I get an empty result list when applying 2 or more, although there are entries in the DB that satisfy the conditions. </p> <p><strong>UPDATE</strong></p> <p>After following Pimgd's suggestion, i ended up with a query that looks like this:</p> <pre><code>SELECT DISTINCT t1.CONF_ID, t1.DTYPE, t1.TOTALPRICE, t1.NAME FROM CONFIGURATION t1 LEFT OUTER JOIN (CONF_COMP t2 JOIN COMPONENT t0 ON (t0.COMPONENTID = t2.COMP_ID)) ON (t2.CONF_ID = t1.CONF_ID) WHERE ((( t0.COMPONENTID IN (SELECT t3.COMPONENTID FROM COMPONENT t3 LEFT OUTER JOIN Component_PROPERTIES t4 ON (t4.Component_COMPONENTID = t3.COMPONENTID) WHERE ((t4.PROPERTIES_KEY = Brand) AND (t4.PROPERTIES = Intel)))) AND t0.COMPONENTID IN (SELECT t6.COMPONENTID FROM COMPONENT t6 LEFT OUTER JOIN Component_PROPERTIES t7 ON (t7.Component_COMPONENTID = t6.COMPONENTID) WHERE ((t7.PROPERTIES_KEY = Capacity) AND t7.PROPERTIES LIKE 4GB%)))) </code></pre> <p>One criteria works, two yield no results.</p> <p>Any help much appreciated!</p>
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    1. COcb.equal(mapJoin.key() mapJoin? Where did you declare mapJoin? Are you sure you're not looking for compJoin?
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    2. COI am not very experienced in Maps as Entity fields, and the reason is that I hardly find a valid reason for having a map in an Entity. Could you please clarify this point, maybe adding a short description of its use?
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    3. COa configuration consists of several components. like a computer that is built using a motherboard, a cpu, ram etc. now, every component has a map of properties, say brand, capacity, etc. I want to get all configurations that have, say a cpu with Intel as the brand and ram with a 4GB capacity.
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