Prepared statements in LuaSQL (was: Re: string dollar literals (for luamacro or tokenf))

[Tomas Guisasola Gorham <tomas@...>]

	Hi Jay

> (Lua SQL still makes me very sad by lacking parameterized queries
> though. Yes, it's better than nothing, Which backends can't support a
> norrmalized form for the most common statements?
	DBMS's are very different in this aspect.

	PostgreSQL [1]:

PREPARE fooplan (int, text, bool, numeric) AS
    INSERT INTO foo VALUES($1, $2, $3, $4);
EXECUTE fooplan(1, 'Hunter Valley', 't', 200.00);

	MySQL [2]:

PREPARE stmt1 FROM 'SELECT SQRT(POW(?,2) + POW(?,2)) AS hypotenuse';
SET @a = 3;
SET @b = 4;
EXECUTE stmt1 USING @a, @b;

	Oracle OCI8 [3]:

INSERT INTO emp VALUES
    (:empno, :ename, :job, :sal, :deptno)

	I think LuaSQL should not define any of these forms, thus exposing
the incompatibilities between the databases.  Anyway, to offer an API
for prepared statements, LuaSQL must define a _standard_ way to declare,
bind the values and execute a prepared statement.  We have discussed that
before, but anyone had time to spend on that front :-(

	Regards,
		Tomás

[1] http://www.postgresql.org/docs/9.1/static/sql-prepare.html
[2] http://dev.mysql.com/doc/refman/5.0/en/sql-syntax-prepared-statements.html
[3] http://docs.oracle.com/cd/B12037_01/appdev.101/b10779/oci04sql.htm