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    <title>topic Keeping track of changes in a large data set? in App Development</title>
    <link>https://community.qlik.com/t5/App-Development/Keeping-track-of-changes-in-a-large-data-set/m-p/1694925#M53148</link>
    <description>&lt;P&gt;Hello! Hope someone could help me with this problem.&lt;/P&gt;&lt;P&gt;I have a large dataset (~2mil records) that is updated periodically, and I need to keep track of the changes in this set. Whenever there's a new update, I'll receive the new data dump with ALL records, not just the updated ones. It looks like this:&lt;/P&gt;&lt;TABLE border="0" width="255px" cellspacing="0" cellpadding="0"&gt;&lt;TBODY&gt;&lt;TR&gt;&lt;TD width="64px" height="15px"&gt;Update&lt;/TD&gt;&lt;TD width="64px" height="15px"&gt;Period&lt;/TD&gt;&lt;TD width="63px" height="15px"&gt;Item&lt;/TD&gt;&lt;TD width="64px" height="15px"&gt;Value&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px" height="75px"&gt;Update 1&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-01&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;A&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;1000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-01&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;B&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;500&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-01&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;C&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;4000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px" height="75px"&gt;Update 2&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-02&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;A&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;1000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-02&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;B&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;1000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-02&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;C&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px" height="75px"&gt;Update 3&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-03&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;A&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;1000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-03&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;B&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;1000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-03&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;C&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;3000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px" height="15px"&gt;Update 4&lt;/TD&gt;&lt;TD width="64px" height="15px"&gt;2020-04&lt;/TD&gt;&lt;TD width="63px" height="15px"&gt;A&lt;/TD&gt;&lt;TD width="64px" height="15px"&gt;1000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px" height="15px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="15px"&gt;2020-04&lt;/TD&gt;&lt;TD width="63px" height="15px"&gt;B&lt;/TD&gt;&lt;TD width="64px" height="15px"&gt;2500&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px" height="15px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="15px"&gt;2020-04&lt;/TD&gt;&lt;TD width="63px" height="15px"&gt;C&lt;/TD&gt;&lt;TD width="64px" height="15px"&gt;3000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px" height="47px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="47px"&gt;2020-04&lt;/TD&gt;&lt;TD width="63px" height="47px"&gt;D&lt;/TD&gt;&lt;TD width="64px" height="47px"&gt;500&lt;/TD&gt;&lt;/TR&gt;&lt;/TBODY&gt;&lt;/TABLE&gt;&lt;P&gt;My question is, what is the best way to model the data to keep track of Value changes?&lt;/P&gt;&lt;P&gt;If I keep all historical records like the above example, I'll end up with ~8 millions records after just 4 updates.&lt;/P&gt;&lt;P&gt;But if I keep only the changes, or the latest record + changes if any, I cannot visualize the changes in a pivot table (the final requirement). Before() doesn't work, since the data is missing:&lt;/P&gt;&lt;P&gt;&lt;span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="sample2.PNG" style="width: 844px;"&gt;&lt;img src="https://community.qlik.com/t5/image/serverpage/image-id/32138i8470DFC3ECD4B458/image-size/large?v=v2&amp;amp;px=999" role="button" title="sample2.PNG" alt="sample2.PNG" /&gt;&lt;/span&gt;&lt;/P&gt;&lt;DIV class="mceNonEditable lia-copypaste-placeholder"&gt;&amp;nbsp;&lt;/DIV&gt;&lt;P&gt;Looking forward to your ideas! If you need any clarifications, please feel free to ask.&lt;/P&gt;&lt;P&gt;&amp;nbsp;&lt;/P&gt;</description>
    <pubDate>Sat, 16 Nov 2024 02:38:26 GMT</pubDate>
    <dc:creator>btrinh</dc:creator>
    <dc:date>2024-11-16T02:38:26Z</dc:date>
    <item>
      <title>Keeping track of changes in a large data set?</title>
      <link>https://community.qlik.com/t5/App-Development/Keeping-track-of-changes-in-a-large-data-set/m-p/1694925#M53148</link>
      <description>&lt;P&gt;Hello! Hope someone could help me with this problem.&lt;/P&gt;&lt;P&gt;I have a large dataset (~2mil records) that is updated periodically, and I need to keep track of the changes in this set. Whenever there's a new update, I'll receive the new data dump with ALL records, not just the updated ones. It looks like this:&lt;/P&gt;&lt;TABLE border="0" width="255px" cellspacing="0" cellpadding="0"&gt;&lt;TBODY&gt;&lt;TR&gt;&lt;TD width="64px" height="15px"&gt;Update&lt;/TD&gt;&lt;TD width="64px" height="15px"&gt;Period&lt;/TD&gt;&lt;TD width="63px" height="15px"&gt;Item&lt;/TD&gt;&lt;TD width="64px" height="15px"&gt;Value&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px" height="75px"&gt;Update 1&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-01&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;A&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;1000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-01&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;B&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;500&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-01&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;C&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;4000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px" height="75px"&gt;Update 2&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-02&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;A&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;1000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-02&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;B&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;1000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-02&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;C&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px" height="75px"&gt;Update 3&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-03&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;A&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;1000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-03&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;B&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;1000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;2020-03&lt;/TD&gt;&lt;TD width="63px" height="25px"&gt;C&lt;/TD&gt;&lt;TD width="64px" height="25px"&gt;3000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px" height="15px"&gt;Update 4&lt;/TD&gt;&lt;TD width="64px" height="15px"&gt;2020-04&lt;/TD&gt;&lt;TD width="63px" height="15px"&gt;A&lt;/TD&gt;&lt;TD width="64px" height="15px"&gt;1000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px" height="15px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="15px"&gt;2020-04&lt;/TD&gt;&lt;TD width="63px" height="15px"&gt;B&lt;/TD&gt;&lt;TD width="64px" height="15px"&gt;2500&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px" height="15px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="15px"&gt;2020-04&lt;/TD&gt;&lt;TD width="63px" height="15px"&gt;C&lt;/TD&gt;&lt;TD width="64px" height="15px"&gt;3000&lt;/TD&gt;&lt;/TR&gt;&lt;TR&gt;&lt;TD width="64px" height="47px"&gt;&amp;nbsp;&lt;/TD&gt;&lt;TD width="64px" height="47px"&gt;2020-04&lt;/TD&gt;&lt;TD width="63px" height="47px"&gt;D&lt;/TD&gt;&lt;TD width="64px" height="47px"&gt;500&lt;/TD&gt;&lt;/TR&gt;&lt;/TBODY&gt;&lt;/TABLE&gt;&lt;P&gt;My question is, what is the best way to model the data to keep track of Value changes?&lt;/P&gt;&lt;P&gt;If I keep all historical records like the above example, I'll end up with ~8 millions records after just 4 updates.&lt;/P&gt;&lt;P&gt;But if I keep only the changes, or the latest record + changes if any, I cannot visualize the changes in a pivot table (the final requirement). Before() doesn't work, since the data is missing:&lt;/P&gt;&lt;P&gt;&lt;span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="sample2.PNG" style="width: 844px;"&gt;&lt;img src="https://community.qlik.com/t5/image/serverpage/image-id/32138i8470DFC3ECD4B458/image-size/large?v=v2&amp;amp;px=999" role="button" title="sample2.PNG" alt="sample2.PNG" /&gt;&lt;/span&gt;&lt;/P&gt;&lt;DIV class="mceNonEditable lia-copypaste-placeholder"&gt;&amp;nbsp;&lt;/DIV&gt;&lt;P&gt;Looking forward to your ideas! If you need any clarifications, please feel free to ask.&lt;/P&gt;&lt;P&gt;&amp;nbsp;&lt;/P&gt;</description>
      <pubDate>Sat, 16 Nov 2024 02:38:26 GMT</pubDate>
      <guid>https://community.qlik.com/t5/App-Development/Keeping-track-of-changes-in-a-large-data-set/m-p/1694925#M53148</guid>
      <dc:creator>btrinh</dc:creator>
      <dc:date>2024-11-16T02:38:26Z</dc:date>
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