Filter and Expression Text

FDO API

 
Filter and Expression Text
 
 
 

In general, commands in FDO do not support the SQL command language (the one exception is the optional SQLCommand). However, to facilitate ease of use for application developers, expressions and filters in FDO can be specified using a textual notation that is based syntactically on expressions and SQL WHERE clauses. The biggest difference between this approach and SQL is that these clauses are not intended to work against tables and columns, but against feature classes, properties, and relationships. For example, a filter to select roads with four or more lanes might look like:

Lanes >= 4

Similarly, a filter to select all PipeNetworks that have at least one Pipe in the proposed state might look like:

Pipes.state = "proposed"

Furthermore, a filter to select all existing parcels whose owner contains the text “Smith” might look like:

state = "existing" and owner like "%Smith%"

Finally, a filter to select all parcels that are either affected or encroached upon by some change might look like:

state in ("affected", "encroached")