New documents added to firebird 2.0 Unstable by Dmitry Yemanov

Changes can be traced in the What's new text file on sourceforge . Some documents are not added yet.

* SQL improvements: 

        1) Introduced SEQUENCE as a synonym for GENERATOR (as per SQL-99) 

        2) Added SQL-99 compliant NEXT VALUE FOR 

        3) Implemented REVOKE ADMIN OPTION FROM statement 

        See also:

        /doc/sql.extentions/README.sequence_generators

        /doc/sql.extentions/README.ddl.txt

* ISQL improvement:

        Command line switch -b to bail out on error when used in non-interactive mode. 

        Also,return an error code to the operating system. 

        See also:/doc/README.isql_enhancements.txt



* Context variables 

        Added support for context variables via RDB$GET_CONTEXT and RDB$SET_CONTEXT system functions 

        See also:/doc/sql.extentions/README.context_variables2



* SQL improvement:

        Allowed PLAN, ROWS and ORDER BY clauses in UPDATE/DELETE statements 

        See also:/doc/sql.extentions/README.select_expressions

        Added an equivalence predicate which behaves exactly as equality/inequality, but treats NULL = NULL as TRUE

        Syntax: A IS [NOT] DISTINCT FROM B 

        See also:/doc/sql.extentions/README.distinct



* More SQL improvements:

        1) Allowed FIRST/SKIP/ROWS/PLAN and ORDER BY clauses in views 

        2) Added CROSS JOIN (A CROSS JOIN B means something like A INNER JOIN B ON 1 = 1 or just FROM A, B) 

        3) Allowed UNION in subqueries and INSERT statement 

        See also:/doc/sql.extentions/README.select_expressions



* UDF improvement:

       Ability to signal SQL NULL via a NULL pointer 

       See also: /doc/sql.extentions/README.ddl.txt

       

* Expression indices:

       Implemented indices based on arbitrary expressions

       Syntax: CREATE [UNIQUE] [ASC[ENDING] | DESC[ENDING]] INDEX  ON  (  ) 

       See also:/doc/sql.extentions/README.expression_indices



* IIF builtin function :

       Added IIF (, , ) as a shortcut for CASE WHEN  THEN  ELSE  END 

       See also:

/doc/sql.extentions/README.iif



* Improved ISQL:

       1) Fixed bug SF #910430 - ISQL and database dialect 

       2) Add SET HEADING ON/OFF option 

       3) Add -M2 command-line option to send output of statistics and plans to the same file than the rest of the output

       See also:/doc/README.isql_enhancements.txt



* New database shutdown modes are introduced Single-user and full

       shutdown modes are implemented 

       See also:/doc/README.shutdown_modes.txt



* Implemented EXECUTE BLOCK statement It is now possible to use dynamic PSQL with this statement 

       See also:/doc/sql.extentions/README.execute_block



* Implemented support for default parameters for stored procedures 

  See also:/doc/sql.extentions/README.default_parameters



* Re-worked logic of updatable views This solves problems with views that are implicitly updatable,but still have update triggers

        See also:/doc/sql.extentions/README.view_updates



* Added SQL200X ROWS clause New syntax to limit amount of records you want to get 

        See also:/doc/sql.extentions/README.rows



* Support for explicit cursor syntax in PSQL It is now possible to declare and use multiple cursors in PSQL 

  See also:/doc/sql.extentions/README.cursors



* Improved PLAN clause Allowed to specify more possible paths for the engine 

        Example: PLAN (A ORDER IDX1 INDEX(IDX2, IDX3)) 

        See also:/doc/sql.extentions/README.plan



* Added LEAVE syntax support PSQL loops now may be marked with labels and terminated in Java style 

        See also:/doc/sql.extentions/README.leave_labels



* Improved ROW_COUNT Now it's possible to get number of selected rows as well 

        See also: /doc/sql.extentions/README.context_variables



* Derived tables support Implemented support for derived tables in DSQL (subqueries in FROM clause) as defined by SQL200X 

       See also:/doc/sql.extentions/README.derived_tables.txt



* New backup technology Implemented fast on-line physical incremental backup facilities 

       See also: /doc/README.nbackup.txt



* Generic cleanup. Various cleaning and tidying up of code, warnings removal,64-bitness cleanup, numerous minor bugfixes