Column->name() # column name in upper-case Column->display_name() # column alias or name in user-supplied case Column->table() # name of table column belongs to, if known Column->function() # a Function object, if it's a computed column
Value objects placeholders, columns, functions, etc.
A new S::S::Func object is created for each function once per prepare, after which, the following methods are available:
name() # function's name, e.g. UPPER alias() # function's alias, e.g. c1 args() # an arrayref of value objects class() # name of package holding func's subroutine, e.g. Bar::MyFuncs subname() # name of func's subroutine, e.g. SQL_FUNCTION_UPPER
At this point, only the name of the class and sub are known, it isn't known whether there actually is a corresponding subroutine in the class. Value objects in the args arrayref may also be unknown at this point: placeholders and column names have not yet been replaced with values.
Each Func object is validated once per execute, during open_tables(). Validation requires the function's package and checks for the existence of a routine named with the function's subname. An error will be generated if the subroutine can't be found.
validate() # checks if the function corresponds to an available subroutine
