List of Supported Formats

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• XML (Extensible Markup Language) Reader/Writer
  • XML Quick Facts
  • Workbench XML Reader Parameters
  • Workbench XML Writer Parameters
  • Feature Representation
    • No Geometry
    • Points
    • Lines
    • Area
    • Text
    • Surfaces
    • Solids
    • Aggregate
  • Mapping File Reference
    • Reader Overview
      • Reader Mapping File Directives
    • Writer Overview
      • Writer Mapping File Directives
    • Writer DEF Lines
      • Using the XML Writer in Append Mode
    • Writer Example
  • xfMap
    • Reading the Input XML Document
      • Mapping Rules
      • Types of Mapping Rules
      • Match and Except Expression
      • Specifying Several Match Expressions for One Mapping Rule
      • Limiting Mapping Rule Activation with Except Expressions
      • Mapping Rule States (activation, execution, suspension, and de-activation)
      • Using Force Elements During Mapping Rule Activation and Deactivation
    • Search-sets
      • Contents of an Active-search-set (Default Contents)
    • Expression Elements (Extract and Literal)
      • Extract Expressions
      • Literal Expressions
      • Example
    • Expression Sequence
    • Feature Mapping Rules
      • FME Feature Construction
      • Feature Type Element
      • Attributes Element
      • FME Feature Construction (defining mapping rules under the <feature-content-map> element)
      • Attribute Element (handling multiple values)
      • Attribute Element (handling optional attributes)
      • Attribute Element (sequenced attributes)
      • Attribute Element (Nillable Attributes)
      • Geometry Element
      • Geometry Builder States (activation, execution, suspension, and de-activation)
      • Geometry Construction
      • Composite Geometry Builders
      • Built-in Geometry Builders
      • Mapping Segmented Geometric Information
      • Geometry Traits (trait element)
      • FME Feature Construction (constructing multiple features at a time)
      • Structure Element
      • References Element
      • Apply References Element
    • Group Mapping Rules
      • Group Construction and Destruction
      • Group Attribute-Sets
      • Group Pipelines
      • Condition Element
      • Persistent Groups
    • Reference Mapping Rules
      • Reference-Set Construction and Destruction
      • Reference-Sets
      • Persistent Reference-Sets
      • refexpr Expressions
      • Example
    • Mapping Rules (Optional Elements)
      • Signature Element
      • Expression Element (parmval Expressions)
      • Use-Mappings Element (supplying the parameters)
      • Use-Mappings Element (implicit arguments)
      • Use-Mappings Element (limiting the active-search-set)
      • Define Element
    • More Expression Elements
      • defnval Expressions
      • strexpr Expressions
      • tclexpr Expressions
      • counter Expressions
      • maprule Expressions
      • selexpr Expressions
      • matched Expressions
      • keyword Expressions
      • fmefunc Expressions
      • logexpr Expressions
      • comparison Expressions
      • uuid Expressions
      • directive_Expressions
    • FME Schema Features
      • Scanning for FME Schema Features
      • Generating FME Schema Features
      • Inline FME Schema Features

Attribute Element (Nillable Attributes)

The <attribute> element has an optional nillable attribute that specifies whether FME should interpret an empty element as an empty string attribute (when the nillable attribute is false or missing), or a null attribute (when the nillable attribute is true).

<attribute nillable="false">
	<name> <literal expr="my-optional-attribute"/> </name>
	<value> <extract expr="."/> </value>
</attribute>