topic Re: Reg type and like in Application Development and Automation Discussions

Reg type and like

Former Member — Fri, 11 Apr 2008 09:14:26 GMT

Hi All,

Often we have been told that type should use instead of like?How it is adavantage is it performance wise it is better?

I have a problem in my report some performance issues I have used type to declare fields in alv int table the reason for this is when i define field using like instead of type the field description is not coming in the output.

Could you please somebody suggest the reason for this?

Please dont tell the difference between type and Like.

Regards

Mahesh

Re: Reg type and like

Former Member — Fri, 11 Apr 2008 09:17:36 GMT

hi,

The ABAP type concept distinguishes between data types and data objects.

o Data types are either defined locally in an ABAP program with TYPES or globally in the ABAP Dictionary.

o Data objects reside in the internal mode of an ABAP program and are declared prototypical with the statement DATA.

When you declare local program data types with TYPES or data objects with DATA, the data type must be defined. To do this you can refer to already existing types in addition to using type constructors, for example, TYPE TABLE OF or TYPE REF TO. It is possible to refer to data types using the TYPE addition and the data object using the LIKE addition. Furthermore, type references are possible using TYPE and LIKE also during typing interface parameters or field symbols.

o TYPE addition

With TYPE addition, you can refer either to local data types of the same ABAP program or on global data types of the Dictionaries.

Local types mask global types that have the same names. When typing the interface parameters or field symbols, a reference is also

possible to generic types ANY, ANY TABLE,INDEX TABLE, TABLE or STANDARD TABLE, SORTED TABLE and HASHED TABLE.

o The LIKE addition

With the LIKE addition, you can refer to all visible data objects

at the ABAP program's positon in question. Only the declaration of

the data object must be known. In this case it is totally

irrelevant whether the data object already exists physically in

memory during the LIKE reference. Local data objects mask global data objects that have the same name.

The semantic separation between data types and data objects is reflected by the syntactic separation in ABAP between TYPE and LIKE. This separation allows for separate namespaces for data types and data objects. Only for reasons of compatibility with preceding releases, can you refer to flat structures (see note 176336) in the ABAP Dictionary with the LIKE addition,

so to database tables and independent flat structures. The LIKE addition first finds a data object on the local program and then in the ABAP Dictionary it finds a database table or flat structure that has the same

name. The type reference on the ABAP Dictionary is no longer possible with

LIKE in the class of ABAP objects. In all ABAP programs, the LIKE reference is forbidden on data elements, internal tables and deep structures of the

ABAP Dictionary.

The TYPE reference to global data types of the ABAP Dictionary is possible as of Release 4.5. At the same time all types of the ABAP type concept can be defined in the ABAP Dictionary as of Release 4.5. Previously there was only an actual equivalent for flat structures between the ABAP data types and the dictionary data types. The structure of database tables and independent structures corresponded to the ABAP data type structure in the dictionary Only with the LIKE addition could database tables and structures be referred to from ABAP programs. In the meantime the LIKE addition should be used in all ABAP programs only for referring to data objects while the TYPE addition is used of the reference to the data type.

Caution should be taken if a flat structure is changed in the dictionary by adding or changing a component into a deep structure. Then a reference with the LIKE reference is syntactically no longer possible and the ABAP

programs must be changed appropriately. As outlined in Note 176336, such a structure change means more than replacing the LIKE with the TYPE addition.

Moreover the use of the structure must also be checked at other positions.

Hope this helps, Do reward.

Re: Reg type and like

Former Member — Fri, 11 Apr 2008 09:19:42 GMT

Hi,

ABAP distinguishes between types and objects. Types are descriptions that do not occupy memory. Objects are instances of types, and do occupy their own memory space. A type describes the technical attributes of all of the objects with that type.

You can use the addition

TYPE <type>

to refer to any data type <type> that is already known at this point in the program.

DATA <f> TYPE <type>.

The data object <f> has a data type corresponding to the type <type>.

DATA <f> LIKE <obj>.

The data object <f> inherits all of the technical attributes of the data object <obj>.

Take an example :

types : begin of ty_tab,

name(30),

pwd(10),

end of ty_tab.

data : itab like ty_tab.

See here we declared the structure of ty_tab, which do not occupy memory. So if we run this, we will get compile time error like this : Field TY_TAB is unknown. It is neither in one of the specified tables nor defined by a DATA statement.

So in this case u need to correct the error with "TYPE" statement...like this.

types : begin of ty_tab,

name(30),

pwd(10),

end of ty_tab.

data : itab type ty_tab.

Refer these

http://help.sap.com/saphelp_nw2004s/helpdata/en/fc/eb2ff3358411d1829f0000e829fbfe/content.htm

Refer this link

Re: LIKE & TYPE

Posted: Jul 23, 2007 6:18 AM in response to: Mohit Goel Reply

For TYPE

http://help.sap.com/saphelp_47x200/helpdata/en/d3/2e974d35c511d1829f0000e829fbfe/frameset.htm

For LIKE

http://help.sap.com/saphelp_47x200/helpdata/en/d3/2e974d35c511d1829f0000e829fbfe/frameset.htm

http://help.sap.com/saphelp_nw2004s/helpdata/en/fc/eb367a358411d1829f0000e829fbfe/content.htm

LIKE means the datatype of the variable is similar to the referenced variable.

TYPE means it is a predefined data type.

Eg:

DATA int TYPE i.

Here int is of integer data type.

DATA var LIKE int.

var IS a variable having same data type of int. which in turn is integer.

You can find these helpful when you reference database table variables... You need not know what is the datatype defined.

Also it adds to FLEXIBILITY.

Whenever you make changes to your database tables and fields,

that change is REFLECTED back to your program that is,

You need not change all your program code when you change your table fields...

2)Passing the table using the TABLES parameters in a function module is one solution. However, using the IMPORT or CHANGING parameters is a better solution. Just create in the Dictionary a table type like your internal table to be able to TYPE your parameters.

ex. DATA: l_vbeln TYPE vbak-vbelln.

DATA: g_vbeln LIKE l_VBELN.

Re: Reg type and like

Former Member — Fri, 11 Apr 2008 09:20:57 GMT

Hi,

LIKE is used for pre defined objects

data: itab like kna1.

like is for declaring data objects

we use TYPE for pre defined datatypes.

data: var type c.

type is for declaring data types

memory will be allocated for data objects while memory is not allocated for data types

Reward Points if found helpfull..

Cheers,

Chandra Sekhar.