Creating Joined Views

GISDK provides flexible tools for creating joined views. You create a joined view by linking any two existing views (either or both of which may be a joined view) based on the value of a single field in in each one. The JoinViews() GISDK function creates joined views and provides a number of options you can use to modify the characteristics and performance of the joined view. The fields on which the views are joined can be expression fields, though the evaluation of the expression will slow down operations on the joined view. You can also use the JoinViewsMulti() GISDK function to create a joined view based on multiple fields.

Here are the GISDK functions you use to create and work with joined views:

GISDK Function	Summary
BuildInternalIndex()	Builds a permanent index on a field in a table
DecideJoinType()	Determines if the right fields of a join have duplicates for aggregation
ExportView()	Exports the contents of a view to a new table file
FieldsSupportAggregations()	Returns a list of fields that support aggregation rules
GetFieldAggregations()	Gets the aggregation rules for a field
GetHardLinkClass()	Gets the class of a table that is hard-linked to a database
JoinTableToLayer()	Permanently joins a single table to a geographic file
JoinViews()	Creates a joined view by linking fields in two existing views
JoinViewsMulti()	Creates a joined view by linking multiple fields in two existing views
SelfAggregate()	Groups the records in a view, based on a field, to create an aggregate view

There are many different types of joined views, and many options you can use to affect performance. For more extensive notes on creating and working with joined views, see the documentation for the JoinViews(), JoinViewsMulti(), and related GISDK functions in the Listing of GISDK Functions.