Function Name	Hour
Category	DateTime
Icon
Description	Retrieve the hour portion of a DateTime value
Inputs	DateTime DateTime value to retrieve hour from
Outputs	Hour Hour value from DateTime input
Properties	None -

Usage

The Data Mapper DateTime Hour function returns the hour portion of a DateTime value. Many applications use DateTime values to record information about events, for example retail or other account transactions. It is often necessary to retrieve particular portions of a DateTime value, such as the hour, or to separate the DateTime into its component parts for the target application. To apply the DateTime Hour 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 sales_source.xsd, an XML Schema Definition inferred from the following source:

<sales>
 <purchase>
  <sale_id>9099879823</sale_id>
  <item_ref>ab65gh7hh7</item_ref>
  <customer_id>34522</customer_id>
  <transaction>2003-01-20T07:15:32.42</transaction>
 </purchase>
 <purchase>
  <sale_id>2390865748</sale_id>
  <item_ref>g7hy65tfd3</item_ref>
  <customer_id>12009</customer_id>
  <transaction>2007-06-12T23:35:10.09</transaction>
 </purchase>
 <purchase>
  <sale_id>8250987123</sale_id>
  <item_ref>d4rf54r0op</item_ref>
  <customer_id>28769</customer_id>
  <transaction>2006-11-27T17:20:09.88</transaction>
 </purchase>
</sales>

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

<transactions>
 <sale id="8987612312" item="y6yt5i93e4">
  <cust_id>14398</cust_id>
  <bought_time>20</bought_time>
 </sale>
 <sale id="2090176549" item="i8u7b45f7y">
  <cust_id>23112</cust_id>
  <bought_time>11</bought_time>
 </sale>
 <sale id="2819283722" item="y6yt5i93e4">
  <cust_id>34309</cust_id>
  <bought_time>09</bought_time>
 </sale>
</transactions>

The data models retail transactions, including the DateTime for when a sale was made. Let's assume that in this case we only want to map the hour at which each transaction took place, perhaps for marketing purposes. Here is the Data Mapper with Source and Target imported:

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

The Hour function takes a single input, the DateTime in question, giving an output comprising the hour 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 Hour value to sort or filter the data in terms of purchases made at different times of day.

Connect the Hour function input to the "transaction" output in the XML Reader and the Hour output to the "bought_time" input in the XML Writer.

Now the only portion of the DateTime mapped will be the hour value. If you want to map more than one part of a DateTime, you can use the other DateTime functions, connecting them each to your source DateTime input and mapping them forward as necessary.

Finally, connect the remaining inputs and outputs:

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

<transactions>
 <sale id="9099879823" item="ab65gh7hh7">
  <cust_id>34522</cust_id>
  <bought_time>7</bought_time>
 </sale>
 <sale id="2390865748" item="g7hy65tfd3">
  <cust_id>12009</cust_id>
  <bought_time>23</bought_time>
 </sale>
 <sale id="8250987123" item="d4rf54r0op">
  <cust_id>28769</cust_id>
  <bought_time>17</bought_time>
 </sale>
</transactions>

The "bought_time" contains an indicator of the hour at which each transaction was made, represented as a number between 0 and 23.