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POUpdating two tables in a many-to-one relationship through a view in PostgreSQL
 

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    <p>I have two tables: <code>foos</code> and <code>bars</code>, and there is a many-to-one relationship between them: each <code>foo</code> can have many <code>bars</code>. I also have a view <code>foobars</code>, which joins these two tables (its query is like <code>select foo.*, bar.id from foos, bars where bar.foo_id=foo.id</code>).</p> <p>EDIT: You would not be wrong if you said that there's a many-to-many relationship between <code>foo</code>s and <code>bar</code>s. A <code>bar</code>, however, is just a tag (in fact, it is a size), and consists just of its name. The table <code>bars</code> has the same role as a link table would have.</p> <p>I have a rule on inserting to <code>foobars</code> such that the “foo” part is inserted to <code>foos</code> as a new row, and “bar” part, which consists of a couple of bar-id's separated by commas is split, and for each such part a link between it and the appropriate <code>foo</code> is created (I use a procedure to do that).</p> <p>This works great for inserts. I have a problem, however, when it comes to updating the whole thing. The <code>foo</code> part of the rule is easy. However, I don't know how to deal with the multiple <code>bar</code>s part. When I try to do something like <code>DELETE FROM bars WHERE foo_id=new.foo_id</code> in the rule, I end deleting everything from the table <code>bars</code>.</p> <p>What am I doing wrong? Is there a way of achieving what I need? Finally, is my approach to the whole thing sensible?</p> <p>(I do this overcomplicated thing with the view because the data I get is in the form of “<code>foo</code> and all its <code>bar</code>s”, but the user must see just <code>foobars</code>.)</p>
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A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

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