topic views in Application Development and Automation Discussions

views

Former Member — Fri, 25 Apr 2008 13:56:51 GMT

HI EXPERTS !

plz tell me the difference between four views .

how i can implement them .

thanks

Re: views

manubhutani — Fri, 25 Apr 2008 14:07:29 GMT

VIEWS – Database view can be built on more than 1 table.

If its built on more than 1 table , then u can not change the values in view.

If its built on 1 table , then u can change the values in view.

there is a tab ‘main status’ where u can choose b/w read only and read/change

this option is disabled if view is built on more than 1 table.

maint views can be built on a no of tables, where u can change the values of this view

and changes are saved in the database tables

help view- obsolete

displays help

please reward points

Re: views

Former Member — Fri, 25 Apr 2008 16:02:56 GMT

Hi Ranjna,

Award points if useful

different types of views are

1.Database view

2.Projection view

3.Maintanence view

4.help view

1. Database View (SE11)

Database views are implement an inner join, that is, only records of the primary table (selected via the join operation) for which the corresponding records of the secondary tables also exist are fetched. Inconsistencies between primary and secondary table could, therefore, lead to a reduced selection set.

In database views, the join conditions can be formulated using equality relationships between any base fields. In the other types of view, they must be taken from existing foreign keys. That is, tables can only be collected in a maintenance or help view if they are linked to one another via foreign keys.

2.Projection View

Projection views are used to suppress or mask certain fields in a table (projection), thus minimizing the number of interfaces. This means that only the data that is actually required is exchanged when the database is accessed.

A projection view can draw upon only one table. Selection conditions cannot be specified for projection views.

3.Maintenance View ( SE54 )

Data from several tables can be summarized in a maintenance view and maintained collectively via this view. That is, the data is entered via the view and then distributed to the underlying tables by the system.

4.Help view

Help views are used to output additional information when the online help system is called.

When the F4 button is pressed for a screen field, a check is first made on whether a matchcode is defined for this field

Re: views

Former Member — Fri, 25 Apr 2008 16:32:34 GMT

Hi Ranjana Sharma ,

A view is a logical view on one or more tables, that is, a view is not actually physically stored, instead being derived from one or more other tables.

In the simplest case, this derivation process can involve simply suppressing the display of one or more fields from a table (projection) or transferring only certain records from a table to the view (selection). More complicated views can be assembled from several tables, with individual tables being linked using the relational join operation.

Use

Logical views for the application permitting direct access to the data can be generated with the definition of view. The structure of such a view is defined by specifying the tables and fields involved in the view.

View Type

The view type defines how a view is implemented and how one can access the view.

Six different view types are supported at the moment:

Database view (type D): implemented with an equivalent view on the database.

Projection view (type P): used to mask out fields from a table.

Help views (type H): used in the online help system.

Structure view (type S): used to generate a structure from the view fields. The creation of structure views is no longer supported as of Release 3.0.

Maintenance view (type C): permits a business view on data and enables maintenance of this data.

Entity view (type E): used to map entity types of the EDM to tables of the ABAP Dictionary. This view type is no longer supported as of Release 3.0.

Database views

The view defined in the ABAP Dictionary is reproduced in the underlying database. You can use both ABAP Open SQL and ABAP Native SQL to access such views from ABAP programs, but you can only define them using transparent tables. If you define a database view using only one table, you can make changes to the view. For database views containing several tables, however, only read accesses are allowed.

Projection views (table projection only)

Projection views are used to suppress certain fields from a table in the interests of minimizing interfaces. A projection view can only refer to one table and, in contrast to database views, you cannot specify any restrictions with regard to table type. This view type also permits both read and write accesses with ABAP Open SQL.

Help views

Help views are used as the selection method of elementary search helps if the selection is too complex to be defined with a single database table. In contrast to database views, help views implement an outer join. For this reason they are suitable for linking supplementary information such as explanatory text from secondary tables. If the supplementary information were missing in an inner join, the entire dataset would not be selected.

If the selection is only to use a table and its text table, it is sufficient to specify the table directly as selection method of the search help since the fields of the text table can also be used as parameters in the search help in this case.

You should not use a help view if you expect the selection to be restricted frequently with fields of the secondary tables. In this case you should create a database view instead. You might also have to create suitable indexes for the base tables.

You can only speed up selection with help views if you restrict the primary table. When accessing help views with the help processor, special selection routines are generated. These routines always first make the selection using the primary table and then use the records found as a key for selecting the supplementary information.

Notes

1. Direct access to help views is not possible.

2. Prior to Release 4.0 help views were automatically used to define the check table help for the primary table of the help view. This is no longer valid as of Release 4.0.

You can get the same effect by creating a suitable search help and attaching it to the check table.

Structure views (no longer supported)

With this view type, the system simply uses the view fields to generate a table structure that you can reference in ABAP/4 programs with the TABLES statement. You can include both transparent tables and the special table types in these views.

Structure views have the same functionality as pure structures. Creation of structure views therefore is no longer supported as of Release 3.0. Existing structure views, however, can still be used.

Maintenance views

Maintenance views provide you with a business view of the data. You can change it either with the table maintenance transaction SM30, which allows you to maintain data from the base tables in a view at the same time, or with the customizing transaction. The mechanisms for data maintenance such as screens and processing programs can be created with a special transaction (SE54).

Entity views

Entity views are used to represent entity types of the Enterprise Data Model (EDM) in ABAP/4 Dictionary tables. You can use any type of view for this purpose but, as long as these views are not used in programs, you define them with type 'E'. No table structures are generated for this type. They are therefore unknown in ABAP/4 but do not place a load on the runtime environment.

Kindly Reward points if useful.

Thanks ,

Surya Pydikondala