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POHQL Left Outer Join for null column in one-to-one relation
 

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  1. POHQL Left Outer Join for null column in one-to-one relation
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    <p>Left outer join is supposed to get all data from left table no matter if there is matching record from B table, however if left tables right_id column is null, records cant be got. </p> <p>I am explaining more</p> <p>In Data model: Order.java, it is my LEFT table, there is a one to one relation</p> <pre><code>@OneToOne(targetEntity = OrderShippingDetail.class, optional=true, cascade = {CascadeType.ALL}) @JoinColumn(name = "SHIPPING_DETAIL_ID", referencedColumnName = "ID") private OrderShippingDetail shippingDetail; </code></pre> <p>and HQL is:</p> <pre><code> hql = "SELECT " + "o.id as id, " + "o.createTime as createTime, " + "o.customerEmailAddress as customerEmailAddress, " + "o.customerPhoneNumber as customerPhoneNumber, " + "o.customerNote as customerNote, " + "o.invoicePrintedFlag as invoicePrintedFlag, " + "shippingAddress.address.personName as shippingPersonName, " + "shippingDetail.shippingCompany.id as shippingCompanyId, "+ "shippingDetail.shippingCompany.name as shippingCompanyName, "+ "shippingDetail.receiptNumber as shippingReceiptNumber, "+ "shippingDetail.trackingNumber as shippingTrackingNumber, "+ "shippingDetail.price as shippingPrice, "+ "o.invoiceNumber as invoiceNumber " + "FROM Order AS o " + "LEFT OUTER JOIN o.shippingAddress AS shippingAddress " + "LEFT OUTER JOIN o.shippingDetail AS shippingDetail "; </code></pre> <p>But there comes just records which "SHIPPING_DETAIL_ID" is NOT null. Is there an error with HQL? It is created by modelling SQL command which is automatically created when hibernate runs. </p> <p>I found this, </p> <blockquote> <p>HQL supports two forms of association joining: implicit and explicit.</p> <p>The queries shown in the previous section all use the explicit form, that is, where the join keyword is explicitly used in the from clause. This is the recommended form.</p> <p>The implicit form does not use the join keyword. Instead, the associations are "dereferenced" using dot-notation. implicit joins can appear in any of the HQL clauses. implicit join result in inner joins in the resulting SQL statement.</p> </blockquote> <p>And I remove my dot notation in the SELECT part, so my new HQL:</p> <pre><code>hql = "SELECT " + "o.id as id, " + "o.createTime as createTime, " + "o.customerEmailAddress as customerEmailAddress, " + "o.customerPhoneNumber as customerPhoneNumber, " + "o.customerNote as customerNote, " + "o.invoicePrintedFlag as invoicePrintedFlag, " + "shippingDetail, " + "o.invoiceNumber as invoiceNumber " + "FROM Order AS o " + "LEFT OUTER JOIN o.shippingAddress AS shippingAddress " + "LEFT OUTER JOIN o.shippingDetail AS shippingDetail "; </code></pre> <p>So, it works, it returns all records in Order table, however, I dont want to select all columns and relations in the ShippingDetail object. What can I do to solve this issue?</p>
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