The Liquid Data Mapper makes building complex data transformations quick and easy, but before you start there are a few basic concepts you need to learn.
The value returned from a connection point is always a sequence of values, i.e. a set of zero or more (0-n) values.
Even if the data source only provides a single value such as an attribute value in an XML document, this is dealt with as a sequence that contains a single value. Similarly if a source value is missing, for example an optional element in an XML document, then an empty sequence is returned.
Notation – For these examples, curly brackets are used to describe the contents of a sequence:
{‘A’} is a sequence containing a single value ‘A’
{} is an empty sequence
{‘A’, ’B’} is sequence containing 2 values ‘A’ & ’B’
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| Liquid Data Mapper – Sequence |
In this simple example we have a ‘Constant’ component value as data input. This provides the simplest possible sequence as it just returns the sequence {‘A’}. So when it is used to create the Name element in the ‘XML Writer’, we get a single Name element with the value ‘A’:
<!–Created by Liquid Data Mapper Libraries (www.liquid-technologies.com)–>
<Contacts>
<ContactDetails>
<Name>A</Name>
</ContactDetails>
</Contacts>
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| Liquid Data Mapper – Sequence |
In this example, three ‘Constant’ components provide input sequences {‘A’}, {‘B’} and {‘C’} and are used as data inputs to the ‘Combine’ component. The ‘Combine’ component combines these into a single sequence {‘A’, ‘B’, ‘C’}. So now as three values are being used to create the Name element in the ‘XML Writer’, we get three Name elements in the XML:
<!–Created by Liquid Data Mapper Libraries (www.liquid-technologies.com)–>
<Contacts>
<ContactDetails>
<Name>A</Name>
<Name>B</Name>
<Name>C</Name>
</ContactDetails>
</Contacts>
Tip: Execute the transform by pressing Shift-F5.Debug the transform by pressing F5 to start the debugger
F11 – Step Into
F9 – Set break point
F5 – Run (stops on break points)
A free trial of the Liquid Data Mapper is available from:
https://www.liquid-technologies.com/trial-download