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ABAP statements allow to specify some parts dynamically.
General syntax: “(token)” where token is a field evaluated at run time.
Rule: The contents of the token must be in upper case.
No static type checks for dynamic statements.
Run time errors occur if the contents of the token are invalid.
There are 5 types of dynamic token specification
1. Dynamic field specification:
The token contains the name of a field
2. Dynamic type specification:
The token contains a type name
3. Dynamic component specification:
The token contains the name of a component of a structure
4. Dynamic clause specification:
The token is an internal table which represents a list of tokens to be inserted and
interpreted at run time
5. Dynamic subroutine specification:
The token contains the name of a form, method, function, program, …
1. Dynamic field specification:
The token contains the name of a field or database table
ASSIGN (field) TO …
SELECT … FROM (dbtab) …
DELETE … FROM (dbtab) …
MODIFY (dbtab) …
UPDATE (dbtab) …
WRITE … TO (field)
WRITE (field) TO …
The dynamic ASSIGN enables parameters being passed dynamically to arbitrary ABAP
statements
eg.
CONSTANTS: a TYPE i VALUE 1,
b TYPE i VALUE 2.
DATA: name(5) TYPE c.
FIELD-SYMBOLS: <i> TYPE i.
* Dynamic ASSIGN to constant a
name = ‘A’.
ASSIGN (name) TO <i>.
WRITE: <i>. “=1
* Dynamic ASSIGN to constant b
name = ‘B’.
ASSIGN (name) TO <i>.
WRITE: <i>. “=2
2. Dynamic Type Specification
The token contains the name of a dictionary (global) or an internal type
ASSIGN … CASTING TYPE (type)
CREATE DATA … TYPE (type) …
eg.
TYPES: BEGIN OF struc,
a TYPE i,
b TYPE p,
END OF struc.
DATA: dref TYPE REF TO DATA.
FIELD-SYMBOLS: <dobj> TYPE any.
PERFORM doSomething USING dref ‘SFLIGHT’.
ASSIGN dref->* to <dobj>.
…
FORM doSomething USING dref TYPE REF TO DATA
tname TYPE strinf. * Create a data object of type ‘tname’
CREATE DATA dref TYPD )tname).
…
ENDFORM.
3. Dynamic Component Specification
The token contains the name of a component of a structure
SORT … BY (comp1) … (compn)
READ TABLE … WITH KEY (k1) = v1 … (kn) = vn
DELETE … COMPARING (comp1) … (compn)
MODIFY … TRANSPORTING (comp1) … (compn)
AT NEW/END OF (comp)
ASSIGN COMPONENT comp OF STRUCTURE …
Empty tokens are ignored in statements for internal tables
eg.
DATA: itab TYPE TABLE OF …,
key1 TYPE string,
key2 TYPE string, …
* Sort table dynamically to set up a dynamic READ with binary search
SORT itab BY (key1) (key2).
READ TABLE itab INTO wa WITH KEY (key1) = val1 (key2) = val2
BINARY SEARCH.
4. Dynamic Clause Specification
Dynamic clause represents a sequence of tokens
The syntax of the clause is checked at run time
SELECT (fieldlist) …
SELECT … GROUP BY (fieldlist)
SELECT … WHERE (condlist)
TYPES: cond(72) TYPE c.
DATA: wa TYPE spfli,
condtab TYPE TABLE OF cond.
* Fill the condition table
APPEND ‘CARRID = ”LH” AND’ TO condtab.
APPEND ‘CITYTO = ”NEW YORK”.’ TO condtab.
* Database fetch with a dynamic WHERE condition
SELECT * FROM spfli INTO wa WHERE (condtab).
WRITE: / wa-carrid, wa-connid, wa-cityfrom, wa-cityto.
ENDSELECT.
5. Dynamic Subroutine Specification
The token contains the name of a form, function, method or program and is
interpreted at run time to execute the corresponding program unit
PERFORM (form) IN PROGRAM (prog) …
SUBMIT (program) …
CALL FUNCTION … PERFORMING (form) …
CALL METHOD oref->(method) …
eg.
DATA: pname TYPE string,
fname TYPE string.
fname = ‘DO_SOMETHING’.
pname = ‘UTILITIES’.
* External PERFORM
PERFORM (fname) IN PROGRAM (pname) USING 999.
