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POBest Practice - Building a query based on user selections
 

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  1. POBest Practice - Building a query based on user selections
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    <p>I am creating a small web based tool that allows users to query a large lookup table in various ways. Since its a small tool, I'm using JSP/Servlets. </p> <p>The lookup table has a definition something like this:</p> <p>column1 | column2 | column3 | date | user | count</p> <p>The user can query by column values or a range. Also, the results can be sorted by a specific column. Because the table has several hundred thousand of records, and growing rapidly, I'm using Oracle's ROWNUM and only returning a small subset of results.</p> <p>I have a form page that gets the search criteria from the user. I generate my query based on a series of conditions, for example:</p> <pre><code>query = "SELECT * FROM mytable WHERE 1=1 " if(searchCriteria1 != "") query += "AND column1='searchCriteria1' " if(searchCriteria2 != "") query += "AND column2='searchCriteria2' " if(searchCriteria2 != "") query += "AND column2='searchCriteria2' " if(searchCriteria3 != "") query += "AND column3='searchCriteria3' " if((searchCriteria4 != "") &amp;&amp; (searchCriteria5 != "")) query += "AND date&gt;='searchCriteria4' AND date&lt;='searchCriteria5' " etc... </code></pre> <p>(This is just simplified pseudo code)</p> <p>The sorting is handled after the first results page is displayed. The user clicks on the column header of that page to sort by that column. This would be doing a post back and querying the database. Basically, I run the same code above but with this at the end:</p> <pre><code>if(sortColumn1) query += "ORDER BY column1" if(sortColumn2) query += "ORDER BY column2" if(sortColumn3) query += "ORDER BY column3" </code></pre> <p>So, as you might imagine, my query building code is very long with all these different conditions. Any suggestions on a better way to do this?</p>
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    1. USJohn Lee
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    1. COWhy cant you sort on the client side using jquery? or any of the other js plugins
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    2. COare you using an ORM layer?
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      1. USdigitaljoel
    3. COFirst of all, I don't think you need to return everything fit the criteria, you only need to return top 100 or even less. Secondly, is it possible to split the large look up table into several small tables, cos I think for some columns, their chances of being searched is much higher than the others, by spliting them and joining them back together at a proper time later can increase the performance. Thirdly, you dont have to do all the sorting in server side i think.
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      1. USLarry
 

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