# Historic for array

**URL:** <https://forum.inductiveautomation.com/t/historic-for-array/11361>\
**Category:** Ignition\
**Created:** [March 14, 2016, 5:33pm UTC](https://forum.inductiveautomation.com/t/historic-for-array/11361 "2016-03-14T17:33:01Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![benoit](https://avatars.discourse-cdn.com/v4/letter/b/5daacb/32.png) [@benoit](https://forum.inductiveautomation.com/u/benoit)\
**Post date:** [March 14, 2016, 5:33pm UTC](https://forum.inductiveautomation.com/t/historic-for-array/11361/1 "2016-03-14T17:33:01Z")

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Hi !

I have some difficulties to retrieve data from historic.  
When I have a look at my SQLserver base, I have some questions about the way data are stored: It seems to me the table saves scalar values, and not array.

My data come for an OPC tree and I have a XML file describing each element. This file is used to generate the SQLTags. Do I have to add/modify something in that file in a case of an array ?

Here is the XML part concerning My array :

`<Tag name="spectrum" path="_Driver01_/ChannelSet/Dynamic/spectrum/" type="OPC">
        <Property name="EngUnit"/>
        <Property name="Documentation">DIID:0 StringID:1234</Property>
        <Property name="PrimaryHistoryProvider">sqlserver</Property>
        <Property name="FormatString">0.00E0</Property>
        <Property name="OPCServer">Ignition OPC-UA Server</Property>
        <Property name="Tooltip">spectrumCompressed</Property>
        <Property name="OpcItemPath">[Driver01]/ChannelSet/Dynamic/spectrum</Property>
        <Property name="HistoryTimestampSource">1</Property>
        <Property name="AccessRights">0</Property>
        <Property name="DataType">9</Property>
        <Property name="HistoricalDeadband">0.0</Property>
        <Property name="EngHigh">1000000.0</Property>
        <Property name="EngLow">0.0</Property>
        <Property name="Deadband">0.0</Property>
        <Property name="ScaledHigh">1000000.0</Property>
        <Property name="RawHigh">1000000.0</Property>
        <Property name="HistoryEnabled">true</Property>
    </Tag>`