Apart from working with table data stored in GDB structure ObjectLand provides the user with a possibility to access external data sources using ODBC tools. External databases (EDB) are considered to be GDB components which consist, in general case, of tables, queries and layers. EDB queries are created on the basis of tables using a constructive method (similar to internal GDB queries described above) or by direct specifying the SQL statement SELECT which determines the request to get records from some external source.
Like records of internal tables and queries of GDB, records of tables and queries of EDB can be linked with map features. The data from linked records can be used when browsing the map and also when building filters.
An EDB layer is a data structure for storing features of different types, analogously to a layer of a GDB map. Features of an EDB layer can be displayed in themes, be edited, be linked with table records etc., similarly to features of map layers.
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