topic Re: logical database in Application Development and Automation Discussions

logical database

Former Member — Fri, 26 Jan 2007 19:12:12 GMT

why we make a logical database

Re: logical database

RichHeilman — Fri, 26 Jan 2007 19:16:20 GMT

That is a very good question. And my answer is, in my 6 years of SAP ABAP experience, I have never and will never, developed one, and I refuse to use them in any custom report program. So, I guess I still leave you with the question....... Why? To me, I have never needed them.

Regards,

Rich Heilman

Re: logical database

krzysztof_konitz4 — Fri, 26 Jan 2007 22:02:51 GMT

I agree with Rich it's difficult to find good reason to create your own logical database. I have over 8 years experience and I created only one just because I wanted to know how to to that

Although if you are ABAP programmer you will sometimes deal with them beacause SAP use them in many reports (a specially the old ones).

If you are begginer in programming logical databases could be useful when you would like to find out connections between some database tables.

They can also be used in some areas for example SAP queries (SQ01).

regards

Krzys

Re: logical database

RaymondGiuseppi — Fri, 26 Jan 2007 22:10:23 GMT

With my opinion, it serve only to accelerate the development of multiples reports by young beginners programmers.

An experienced programmer defines the framework of the developments with the logical database. Other programmers do not have any more but to use some GET and GET LATE to develop their states. To even develop queries. and they get selection-screen and links between tables for free.

Such a development can only be adviseable if numerous reports/queries are to be developped. So if you don't work for SAP, forget it except for fun of course.

regards

Re: logical database

Former Member — Fri, 26 Jan 2007 22:16:35 GMT

Hi,

As Rich has mentioned, we rarely use Logical Databases, but can modify the standard LDBs like PNP, AFI and customize to your needs.

What is the need? Based on the requirement you can create a selection screen, fetch data by joining one or more tables to the base table.

When this included in your program, your job is to include the LDB and use a GET stmt to read the values in that node.

This GET acts like a loop.

Generally no one advises to use a LDB, because of performance issues, if several tables are linked. You may be interested in only a few of them, but the LDB fetches all the relevant data for all the tables.

Regards

Subramanian

Re: logical database

amit_khare — Fri, 26 Jan 2007 22:35:51 GMT

Hi,

Basically we use logical databases to get the predefined screens and validations.

A Logical Database is a hierarchical structure of tables. Use the GET statement to process Logical Databases.

- LDB consists of logically related tables grouped together – used for reading and processing data.

- Advantages = 1. No need of programming for retrieval , meaning for data selection

- 2. Easy to use standard user interface, have check completeness of user input.

Disadvantages = 1. Fast in case of lesser no. of tables But if the table is in the lowest level of hierarchy, all upper level tables should be read so performance is slower.

But as mentioned before also that theoir usage always provide extra performance issues in programs.

But as an added advantage it reduces coding.

I am working with HR and came across many incidence where they are very handy.

Even before i had worked with FI objects and find it useful for filling hefty tables.

You may go thru this link too

Regards,

Amit

Re: logical database

abdul_hakim — Sat, 27 Jan 2007 04:17:56 GMT

Hi,

LDB is used to access data records from logically dependent tables.

With LDB you can access the tables without/less coding.

Mainly used in HR Modules.

Cheers,

Hakim

Re: logical database

Former Member — Fri, 16 Feb 2007 10:03:08 GMT

Although LDB's are not used, in my area FI-TR , we make extensive use of LDB's .

Mainly because , the fields such as NPV values etc. calculations are complex and they are many reports which require them. Hence we make use of LDB's.

Re: logical database

sreeramkumar_madisetty — Fri, 16 Feb 2007 10:06:40 GMT

Though i agreed with Rich answer.

Without using LDB's how we can create Dynamic Selection-Screens in the programs?

Why can't we consider this as an need to go for LDB?

Regards,

kumar