! main program using SQLDA

! ***************************

 

program dynamic_hdlr

   

    exec sql include sqlca

    exec sql include sqlda

! Do not declare the data handlers nor the data handler

! argument to the ESQL preprocessor

 

external     integerPut_Handler

external     integerGet_Handler

! Declare argument to be passed to data handler

 

record        hdlr_arg

     string        argstr

     integer    argint

end record hdlr_arg

! Declare SQLDA and IISQLHDLR

 

common (sqlda_area) IISQLDA sqlda

common (result_area) num_store     nums(IISQ_MAX_COLS), &

                            char_store chars

 

declare IISQLHDLR    data_handler

declare hdlr_arg     hdlarg

declare         integer     base_type

! Declare null indicator to ESQL

 

exec sql begin declare section

     word             indvar

     string    (100)    stmt_buf

     integer        i

exec sql end declare section

    ...

! Set the IISQLHDLR structure with the appropriate

! data handler and data handler argument.

 

data_handler::sqlhdlr = loc(Get_Handler)

data_handler::sqlarg  = loc(hdlarg)

 

! Describe the statment into the SQLDA

stmt_buf = 'select * from book'.

exec sql prepare stmt from :stmt_buf

exec sql describe stmt into sqlda

...

 

! Determine the base_type of the SQLDATA variables

    while ( i < sqlda::sqld)

        i = i + 1

        if (sqlda::sqlvar(i)::sqltype > 0) then

            base_type = sqlda::sqlvar(I)::sqltype

        else

             base_type = -sqlda::sqlvar(i)::sqltype

        end if

! Set the sqltype, sqldata and sqlind for each column

! The long varchar column chapter_text will be set to

! use a data handler

     if (base_type = IISQ_LVCH_TYPE) then

            sqlda::sqlvar(i)::sqltype = IISQ_HDLR_TYPE

            sqlda::sqlvar(i)::sqldata = loc(data_handler)

            sqlda::sqlvar(i)::sqlind = loc(indvar)

     else

    .    .    .

     end if

    next

! The Data handler (Get_Handler) will be invoked for
! each non-null value of column chapter_text retrieved.
! For null values the indicator variable will be
! set to "-1" and the data handler will not be called

...

    exec sql execute immediate :stmt_buf using :SQLDA
    exec sql begin
         process row...
    exec sql end
    ...

end program