OperationHandle :: CheckExpression - Check validity of an expression

Implementation overview

• Check expression defined in a ODC_ImpClass
  OperationHandle :: CheckExpression ( dicthdl, res_obhandle, clsnames, exprnames, impnames )
• Check inline expression
  OperationHandle :: CheckExpression ( dicthdl, expression, obhandle_ref, clsnames )

Implementation details

1. Check expression defined in a ODC_ImpClass
   logical OperationHandle  :: CheckExpression ( DictionaryHandle &dicthdl, DBObjectHandle &res_obhandle, NString &clsnames, NString &exprnames, NString &impnames )
   

   • dicthdl - Reference to dictionary handle

     This is a reference to an opened dictionary handle.

   • res_obhandle - Reference to resource database object handle

     The resource database handle usually is a database handle, which is referred to as database object handle.

   • clsnames - Class name

     sys_ident of a ODC_ImpClass , used to create a TypeKey in conjunction with nsid

   • exprnames - Expression name
   • impnames - Implementation name
to list
2. Check inline expression
   logical OperationHandle  :: CheckExpression ( DictionaryHandle &dicthdl, NString &expression, DBObjectHandle &obhandle_ref, NString &clsnames )
   

   The scope for the inline expression is defined by the class name passed in classnames .

   • dicthdl - Reference to dictionary handle

     This is a reference to an opened dictionary handle.

   • expression - Inline expression

     An ad hoc expression can be passed as operand (something like a + b) or as complete expression. As operand, an expression may contain any expression, which is allowed in a statement, but no semicolon should be appended. Complete expressions include expression header (optional) and may include different sections in the expression body which is enclosed in { ... }.

     In contrast to class expressions, ad hoc expressions are not defined explicitly as class expressions but passed as strings to the application at run time.

     operand: a + funct(b)

     complete expression :

     bool expr(int a)

     {

     return(a*a);

     }

   • obhandle_ref - Reference to database object handle

     The reference refers to an opened or not opened database object handle.

   • clsnames - Class name

     sys_ident of a ODC_ImpClass , used to create a TypeKey in conjunction with nsid

to list