Difference between Class Pool program and Interface Pool program

[Former Member]

Both Class Pool program and an Interface Pool program indicate that the program contains interfaces that other programs can use globally. What exactly is the difference between them?

[Former Member]

Hi,

refer this:

Interface Pools (J)

Contain interfaces. Classes and interfaces are managed (administered)

in the Class Builder; program type J cannot be changed in the attributes.

it contains: propporties, intrefaces, attibutes, methods, events types, and aliases

where as class pools have : propporties, intrefaces, attibutes, methods, events types, and aliases

Interfaces

The components of a class are divided into visibility sections, and this forms the external point of contact between the class and its users. For example, the components of the public section form the public interface of the class, since all attributes and method parameters can be accessed by any user. The protected components form an interface between the class and those classes that inherit from it (subclasses

Classes

The type of an object is known as its class. A class is an abstract representation, or, metaphorically speaking, a set of instructions for building objects. So that you can describe the properties of objects, classes contain components, which define the state and behavior of objects.

Global and Local Classes

You can define classes globally in the class library in the repository or locally in an ABAP program.

Global classes are coded in a special ABAP program, a class pool, whereas local classes can be coded in almost every ABAP program. Global classes can be used and are visible in all ABAP programs, which is the case for local classes only in their own program. When a global class is used for the first time, the class pool is loaded into the internal mode of the user. The local classes of a class pool can be used by the pool's global classes.

Class Pools (K)

Contain interfaces. Classes and interfaces are managed (administered)

in the Class Builder; program type K cannot be changed in the attributes.

Jogdand M B

Message was edited by:

Jogdand M B

[Former Member]

Hi,

Interface program

http://help.sap.com/saphelp_erp2005/helpdata/en/64/be5b4150b38147e10000000a1550b0/frameset.htm

INTERFACE programs are the ones which are run at regular intervals, say weekly, monthly or even daily. Here the legacy system continues to co-exist along with SAP system, the legacy system might be useful for certain functionalities but the data might have to run thru SAP transactions for complex data maintenance at regular intervals.

Class Pools are nothing but creating CLASSes and INTERFACEs using the T Code SE24.

This needs little Java/OOPs concepts to create and use them

go through this link

http://help.sap.com/saphelp_nw2004s/helpdata/en/ec/d9ab291b0b11d295400000e8353423/content.htm

Regards

[Former Member]

Hi,

Class is a description of an object, which contains both definition and implementation of methods which also includes interface methods.

In contrast, Interfaces contains only methods definition with signature but no methods implementation.

U can refer this link

<a href="http://help.sap.com/saphelp_nw2004s/helpdata/en/ec/d9ab291b0b11d295400000e8353423/content.htm">Class and Interface Pools</a>

Thanks & Regards

Santhosh

[Former Member]

Transparent Table :

Exists with the same structure both in dictionary as well as in database exactly with the same data and fields.

" Pooled Table :

Pooled tables are logical tables that must be assigned to a table pool when they are defined. Pooled tables are used to store control data. Several pooled tables can be cominied in a table pool. The data of these pooled tables are then sorted in a common table in the database.

" Cluster Table :

Cluster tables are logical tables that must be assigned to a table cluster when they are defined. Cluster tables can be used to strore control data. They can also be used to store temporary data or texts, such as documentation.

" what is the major difference between Standard tables, Pooled tables and

" Clusterd Tables?

A transparent table is a table that stores data directly. You can read these tables directly on the database from outside SAP with for instance an SQL statement.

Transparent table is a one to one relation table i.e. when you create one transparent table then exactly same table will create in data base and if is basically used to store transaction data.

A clustered and a pooled table cannot be read from outside SAP because certain data are clustered and pooled in one field.

One of the possible reasons is for instance that their content can be variable in length and build up. Database manipulations in Abap are limited as well.

But pool and cluster table is a many to one relationship table. This means many pool table store in a database table which is know as table pool.

All the pool table stored table in table pool does not need to have any foreign key relationship but in the case of cluster table it is must. And pool and cluster table is basically use to store application data.

Table pool can contain 10 to 1000 small pool table which has 10 to 100 records. But cluster table can contain very big but few (1 to 10) cluster table.

For pool and cluster table you can create secondary index and you can use select distinct, group for pool and cluster table. You can use native SQL statement for pool and cluster table.

A structure is a table without data. It is only filled by program logic at the moment it is needed starting from tables.

A view is a way of looking at the contents of tables. It only contains the combination of the tables at the basis and the way the data needs to be represented. You actually call directly upon the underlying tables.

. Transparent tables (BKPF, VBAK, VBAP, KNA1, COEP)

Allows secondary indexes (SE11->Display Table->Indexes)

Can be buffered (SE11->Display Table->technical settings) Heavily updated tables should not be buffered.

II. Pool Tables (match codes, look up tables)

Should be accessed via primary key or

Should be buffered (SE11->Display Table->technical settings)

No secondary indexes

Select * is Ok because all columns retrieved anyway

III. Cluster Tables (BSEG,BSEC)

Should be accessed via primary key - very fast retrieval otherwise very slow

No secondary indexes

Select * is Ok because all columns retrieved anyway.

Performing an operation on multiple rows is more efficient than single row operations.

Therefore you still want to select into an internal table.

If many rows are being selected into the internal table,

you might still like to retrieve specific columns to cut down on the memory required.

Statistical SQL functions (SUM, AVG, MIN, MAX, etc) not supported

Can not be buffered

IV. Buffered Tables (includes both Transparent & Pool Tables)

While buffering database tables in program memory (SELECT into internal table) is generally a good idea for performance,

it is not always necessary.

Some tables are already buffered in memory.

These are mostly configuration tables.

If a table is already buffered, then a select statement against it is very fast.

To determine if a table is buffered, choose the 'technical settings' soft button from the data dictionary

display of a table (SE12). Pool tables should all be buffered.

More at this link.

http://help.sap.com/saphelp_erp2004/helpdata/en/81/415d363640933fe10000009b38f839/frameset.htm

Transparent Table:

Exists with the same structure both in dictionary as well as in database exactly with the same data and fields.

Pooled Table:

Pooled tables are logical tables that must be assigned to a table pool when they are defined. Pooled tables are used to store control data. Several pooled tables can be cominied in a table pool. The data of these pooled tables are then sorted in a common table in the database.

Cluster Table:

Cluster tables are logical tables that must be assigned to a table cluster when they are defined. Cluster tables can be used to strore control data. They can also be used to store temporary data or texts, such as documentation.

A transparent table is a table that stores data directly. You can read these tables directly on the database from outside SAP with for instance an SQL statement.

Transparent table is a one to one relation table i.e. when you create one transparent table then exactly same table will create in data base and if is basically used to store transaction data.

A clustered and a pooled table cannot be read from outside SAP because certain data are clustered and pooled in one field.

One of the possible reasons is for instance that their content can be variable in length and build up. Database manipulations in Abap are limited as well.

But pool and cluster table is a many to one relationship table. This means many pool table store in a database table which is know as table pool.

All the pool table stored table in table pool does not need to have any foreign key relationship but in the case of cluster table it is must. And pool and cluster table is basically use to store application data.

Table pool can contain 10 to 1000 small pool table which has 10 to 100 records. But cluster table can contain very big but few (1 to 10) cluster table.

For pool and cluster table you can create secondary index and you can use select distinct, group for pool and cluster table. You can use native SQL statement for pool and cluster table.

A structure is a table without data. It is only filled by program logic at the moment it is needed starting from tables.

A view is a way of looking at the contents of tables. It only contains the combination of the tables at the basis and the way the data needs to be represented. You actually call directly upon the underlying tables.

http://www.datamanagementgroup.com/Resources/Articles/Article_0106_2.asp

more info

http://help.sap.com/saphelp_erp2004/helpdata/en/81/415d363640933fe10000009b38f839/frameset.htm

http://cma.zdnet.com/book/abap/ch03/ch03.htm

Check this links.

http://help.sap.com/saphelp_40b/helpdata/en/4f/991f82446d11d189700000e8322d00/applet.htm

http://www.techinterviews.com/?p=198