* -- support for OUT parameters
* -- unique condition in scope
* -- support for SQLSTATE and SQLCODE variables
* -- cursor supports
* -- continue, exit not found handler
* -- automatic closing cursor when block is leaving
* -- signal, resignal statements
* -- condition support
* -- statement for
* -- get diagnostics statement

* clean nested plans of FOR statement
* array support, composite types support
* exception handling, undo handlers support
* triggers support
* simple expression
* embeded SQL
* table functions - RETURN TABLE
* dynamic SQL


PostgreSQL ToDo:
================
* new field "condition_name" in ErrorData
