Liquid Studio Documentation
Data Mapping / Data Mapper Functions / By Category / Date Time / Second
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    Function Name
    Retrieve the second portion of a DateTime value
    DateTime DateTime value to retrieve second from
    Second Second value from DateTime input
    None -


    The Data Mapper DateTime Second function returns the second portion of a DateTime value. Many applications use DateTime values to record information about events, for example to process data such as weather incidents. It is often necessary to retrieve particular portions of a DateTime value, such as the second, or to separate the DateTime into its component parts for the target application. To apply the DateTime Second function, use the following process:

    Create a new Data Mapper file, dragging your XML data source and targets into the editor area. For this example we are using weather_source.xsd, an XML Schema Definition inferred from the following source:

    Source XML
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      <incident_type>Tidal Wave</incident_type>

    For our target schema we will be using weather_target.xsd, inferred from the following XML:

    Target XML
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     <incident type="lightning" severity="7">
      <time type="second">12</time>
     <incident type="tornado" severity="10">
      <time type="second">39</time>

    The data models weather events, including the DateTime for when an incident was recorded. Let's assume that in this case we want to map the second within the minute that each event occurred. Here is the Data Mapper with Source and Target imported:

    Data Mapper Source and Target

    Drag the DateTime Second function from the Component Palette into the mapping area:

    Second Component

    Second Transform Added

    The Second function takes a single input, the DateTime in question, giving an output comprising the second portion. The input should be connected to the source item, which will normally be an item in the XML Reader. The output should be connected to the target item, whether an item in the XML Writer or another component in the Mapper, for example if you plan on using the Second value to sort or filter the data.

    We want to map the "recorded" DateTime value to the "time" element in our target, so connect these between Reader and Writer.

    Reader to Writer

    Now connect the Second function input also to the "recorded" output in the XML Reader and the Second output to the Element Value for the "time" element in the XML Writer, so that the content of the element will be the second part of the DateTime.

    Second Mapped

    Remember that the target XML has an attribute in the "time" element indicating the type of time data in question. To add this, let's drag a Constant Value from the Data Type section onto the Mapper. Right-click it, choosing Show Properties. Select a String Data Type and enter "second" as the value.

    Constant Properties

    Now connect the Constant output to the "type" attribute input for the "time" element in the XML Writer.

    Constant Added

    Finally, connect the remaining inputs and outputs between Reader and Writer:

    Input and Output Connections Mapped

    We can now execute the transform by pressing Shift-F5 or the Execute button (Execute). The transform is applied and the file we selected as output opens in the editor:

    Output XML
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     <incident type="Tidal Wave" severity="5">
      <time type="second">45</time>
     <incident type="Hurricane" severity="9">
      <time type="second">12</time>

    The output contains the second portion of each DateTime value for a single incident, represented as a number between 0 and 59.

    If you pass a value to the Second function that is not a DateTime, the Mapper will attempt to parse it. If you pass the Second function a DateTime value which does not contain a second portion, the function will output a value of 0 by default.

    This is a scalar function so the standard rules apply if multiple values are presented to one or more inputs.

    See Also