FeatureReader

Receives features that initiate feature reading.

Generic output port for features that do not have a corresponding named output port.

Output port for schema features. If connected, a schema feature is produced for each unique feature type encountered during read. The schema feature is guaranteed to be output before any data features of the same feature type and is output only once per translation.

Schema reading may affect performance. If the schema feature output port is not connected or Features to Output is set to Only Data Features, then schema reading will not occur and there will be no performance penalty. If a list of feature types to read was specified then schema reading will stop as soon as schemas for all the listed feature types have been output. If no feature types to read were listed, then schema reading will occur on every Initiator feature.

Performance can be improved when only reading schemas by configuring the transformer to not read data features. This is done by setting Features to Output to Only Schema Features or by ensuring that the <Generic>, the Initiator, and the named feature type output ports are not connected.

Parameters for Constraints or for Attribute and Geometry Handling do not apply to schema features.

Upon read success, outputs the original Initiator features with the addition of the _matched_records attributes which holds the number of features read for that Initiator feature.

Upon reader error, outputs the original Initiator feature with the addition of the _reader_error attribute which contains the last error message from the reader.

Enter the feature types that will be read. Feature types can be selected from a list generated by the reader by clicking the Browse button. For some formats, the parameter can be left empty to indicate all feature types should be read.

When published, this parameter can be represented as a fixed list, a fixed list with aliases, or left as a dynamic list that determines the feature types at runtime.

Select feature types to read from an existing attribute. The chosen attribute can contain multiple feature types where each feature type is separated by spaces. If the feature type contains a space or a double quote, then quote the feature type name with double quotes and escape any internal double quotes with an additional double quote. For example, a feature type named 'my "special" table' would become '"my ""special"" table"'.

Note: Older versions of the FeatureReader using colon as a separator will work as before, but can be updated (see Feature Type Separator).

For formats that support it, only features that fulfill the WHERE clause will be read.

Select only features that fulfill the specified spatial relationship with the Initiator feature. See Spatial Relations Defined for a description of the permitted spatial relations. Select <No Spatial Filter> when no spatial filtering is desired. Select Envelope Intersects to read only those features whose envelope intersects the Initiator feature’s envelope.

The performance of the Spatial Filter can vary depending on the spatial filter being applied and whether the reader supports a Spatial Index. Spatial Filtering is done in two steps: first the candidate features are read, then the more costly filter is applied. For readers that support a Spatial Index, the candidate features are fetched by performing a search envelope on the reader which can greatly improve performance as not all features are read. For readers that do not support a Spatial Index or when the relationship Disjoint is selected, all features are considered candidate features and so all features are read. Check the format’s Quick Facts section to see if the reader supports a Spatial Index.

Note that when setting the Spatial Filter from an attribute, the attribute value can be any of the options found in the drop down list.

Output ports are generated for each feature type specified in the Feature Types parameter. This option is not available if Feature Types to Read is From Attribute.

No additional output ports are generated. All feature types will exit out of the generic output port

Enter a list of feature types that will be used to generate the output ports. Feature types can also be selected from a list generated by the reader by clicking the Browse button.

Merge Initiator and Result: Output features will contain all of the un-conflicted attributes from the results of the read as well as any un-conflicted attributes from the Initiator feature. This mode will handle conflicted attributes based on the Conflict Resolution parameter.

Only Use Result: Output features will contain only attributes resulting from the read.

Only Use Initiator: Output features will contain all of the attributes from the Initiator feature, but none of the attributes resulting from the read.

Prefix Initiator: Output features will contain attributes resulting from the read, as well as attributes from the Initiator feature but with the Initiator attribute names prefixed with the Prefix parameter.

Use Result: If a conflict occurs, the values resulting from the read will be used.

Use Initiator: If a conflict occurs, the values of the Initiator will be used.

If the Accumulation Mode parameter is set to Prefix Initiator, this value will prefix attributes from the Initiator feature.

Result: The feature geometry from the results of the read is used.

Initiator: The feature geometry from the Initiator feature is used.

Aggregate Initiator and Result: The feature geometry is an aggregate of the geometry from the Initiator feature followed by the geometry from the result of the read. The aggregate geometry will be tagged with the coordinate system from the result of the read. The Initiator geometry will not be reprojected. This can create unexpected results if it is in a different coordinate system. For best results, ensure the Initiator geometry has the same coordinate system as the geometry being read.

Enter the names of attributes to expose on the generic output port. The attributes will be ordered in the same sequence as specified in the list.

By default, this transformer will reread the original source data for each Initiator feature. To improve performance (for example, with web services, databases, or URLs), you can choose to create a preprocessed cache to improve the speed when rereading the original source data.

The cache will expire after the specified time interval, or if the original data file is modified.

Note: Note that the Cache Timeout value is also a component of the preprocessed cache. This means that different values of Cache Timeout will correspond to different versions of the cached dataset. For example, if the FeatureReader is set with a Cache Timeout of 1 hour, then set a second time with the same dataset, but with a Cache Timeout of 2 hours, there will be two cached copies of this dataset.

Based on Connections: Schema features and Data features will be read and output based on whether their corresponding output ports are connected. For data features this includes the Initiator, <Generic> and named feature type output ports. For schema features it is the <Schema> output port.

Only Schema Features: Only schema features will be read and output, data features will not be read.

Only Data Features: Only data features will be read and output, schema features will not be read.

This option allows older versions of the FeatureReader to change the separator for multiple feature types in an attribute to be a space instead of a colon. The colon separator is deprecated; once space has been selected, colon cannot be re-selected.

This option is only available to versions 4 and older of the FeatureReader that had been upgraded to version 5 or newer and that were specifying feature types to read from an attribute. When present, this option is only available in the Navigator Window.