mariadb/Docs/sp-implemented.txt
unknown 565d98958e Some new stuff in the Docs/sp-* files, and renamed a few functions in preparation
for future work.


Docs/sp-imp-spec.txt:
  Started on the FUNCTION parts...
Docs/sp-implemented.txt:
  Added som info on SET behaviour, and added Open questions.
sql/sp.cc:
  Renamed functions.
sql/sp.h:
  Renamed functions.
sql/sql_parse.cc:
  Renamed functions.
2003-02-04 17:40:18 +01:00

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Text

Stored Procedures implemented 2003-02-02:
Summary of Not Yet Implemented:
- FUNCTIONs
- Routine characteristics
- External languages
- Access control
- Prepared SP caching; SPs are fetched and reparsed at each call
- SQL-99 COMMIT (related to BEGIN/END)
- DECLARE CURSOR ...
- FOR-loops (as it requires cursors)
Summary of what's implemented:
- SQL PROCEDURES (CREATE/DROP)
- CALL
- DECLARE of local variables
- BEGIN/END, SET, CASE, IF, LOOP, WHILE, REPEAT, ITERATE, LEAVE
- SELECT INTO local variables
List of what's implemented:
- CREATE PROCEDURE name ( args ) body
No routine characteristics yet.
- ALTER PROCEDURE name ...
Is parsed, but a no-op (as there are no characteristics implemented yet).
CASCADE/RESTRICT is not implemented (and CASCADE probably will not be).
- DROP PROCEDURE name
CASCADE/RESTRICT is not implemented (and CASCADE probably will not be).
- CALL name (args)
OUT and INOUT parameters are only supported for local variables, and
therefore only useful when calling such procedures from within another
procedure.
Note: For the time being, when a procedure with OUT/INOUT parameter is
called, the out values are silently discarded. In the future, this
will either generate an error message, or it might even work to
call all procedures from the top-level.
- Procedure body:
- BEGIN/END
Is parsed, but not the real thing with (optional) transaction
control, it only serves as block syntax for multiple statements (and
local variable binding).
Note: Multiple statements requires a client that can send bodies
containing ";". This is handled in the CLI clients mysql and
mysqltest with the "delimiter" command. Changing the end-of-query
delimiter ";" to for instance "|" allows
- SET of local variables
Implemented as part of the pre-existing SET syntax. This allows an
extended syntax of "SET a=x, b=y, ..." where different variable types
(SP local and global) can be mixed. This also allows combinations
of local variables and some options that only make sense for
global/system variables; in that case the options are accepted but
ignored.
- The flow control constructs: CASE, IF, LOOP, WHILE, ITERATE and LEAVE
are fully implemented.
- SELECT ... INTO local variables (as well as global session variables)
is implemented. (Note: This is not SQL-99 feature, but common in other
databases.)
Open questions:
- What is the expected result when creating a procedure with a name that
already exists? An error or overwrite?
- Do PROCEDUREs and FUNCTIONs share namespace or not? I think not, but the
we need to flag the type in the mysql.proc table and the name alone is
not a unique key any more, or, we have separate tables.
(Unfortunately, mysql.func is already taken. Use "sfunc" and maybe even
rename "proc" into "sproc" while we still can, for consistency?)
- SQL-99 variables and parameters are typed. For the present we don't do
any type checking, since this is the way MySQL works. I still don't know
if we should keep it this way, or implement type checking.