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<TITLE>Sams Teach Yourself ABAP/4® in 21 Days -- Day 3- The Data Dictionary, Part 1</TITLE>
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<H1>Sams Teach Yourself ABAP/4<sup>®</sup> in 21 Days</H1></CENTER>
<HR SIZE=4>
<H1>Day 3</H1>
<H1>The Data Dictionary, Part 1</H1>
<UL>
<LI><A HREF="#ChapterObjectives">
Chapter Objectives</A>
<LI><A HREF="#DiscoveringRReleaseLevels">
Discovering R/3 Release Levels</A>
<LI><A HREF="#DelvingDeeperintotheRDataDictionary">
Delving Deeper into the R/3 Data Dictionary</A>
<LI><A HREF="#ExploringtheTypesofTablesinR">
Exploring the Types of Tables in R/3</A>
<UL>
<LI><A HREF="#TransparentTables">
Transparent Tables</A>
<LI><A HREF="#TablePoolsandPooledTables">
Table Pools and Pooled Tables</A>
<LI><A HREF="#TableClustersandClusterTables">
Table Clusters and Cluster Tables</A>
<LI><A HREF="#RestrictionsonPooledandClusterTables">
Restrictions on Pooled and Cluster Tables</A>
</UL>
<LI><A HREF="#ExploringTableComponents">
Exploring Table Components</A>
<UL>
<LI><A HREF="#MaintainingTechnicalCharacteristicsofFields">
Maintaining Technical Characteristics of Fields</A>
<LI><A HREF="#DeterminingWhentoCreateorReuseDomainsandDataElements">
Determining When to Create or Reuse Domains and Data Elements
</A>
</UL>
<LI><A HREF="#NamingConventionsforTablesandTheirComponents">
Naming Conventions for Tables and Their Components</A>
<LI><A HREF="#CreatingaTransparentTableandItsComponents">
Creating a Transparent Table and Its Components</A>
<UL>
<LI><A HREF="#ApproachesforCreatingTables">
Approaches for Creating Tables</A>
<LI><A HREF="#ActivationofDDICObjects">
Activation of DDIC Objects</A>
<LI><A HREF="#DiscoveringDomains">
Discovering Domains</A>
<LI><A HREF="#DiscoveringDataElements">
Discovering Data Elements</A>
<LI><A HREF="#DiscoveringTransparentTables">
Discovering Transparent Tables</A>
</UL>
<LI><A HREF="#ModifyingTables">
Modifying Tables</A>
<UL>
<LI><A HREF="#CopyingaTable">
Copying a Table</A>
<LI><A HREF="#DeletingaTable">
Deleting a Table</A>
<LI><A HREF="#AddingFields">
Adding Fields</A>
<LI><A HREF="#DeletingFields">
Deleting Fields</A>
<LI><A HREF="#ChangingtheDataTypeorLengthofaField">
Changing the Data Type or Length of a Field</A>
</UL>
<LI><A HREF="#WorkingwithData">
Working with Data</A>
<UL>
<LI><A HREF="#AccessingDataBrowserFunctionalityFromWithintheDDIC">
Accessing Data Browser Functionality From Within the DDIC
</A>
<LI><A HREF="#GeneralDataBrowserUtilities">
General Data Browser Utilities</A>
<LI><A HREF="#DisplayingtheDataUsingYourOwnABAPProgram">
Displaying the Data Using Your Own ABAP/4 Program</A>
<LI><A HREF="#UtilizingFHelp">
Utilizing F1 Help</A>
</UL>
<LI><A HREF="#Summary">
Summary</A>
<LI><A HREF="#QampA">
Q&A</A>
<LI><A HREF="#Workshop">
Workshop</A>
<UL>
<LI><A HREF="#Quiz">
Quiz</A>
<LI><A HREF="#Exercise1">
Exercise 1</A>
<LI><A HREF="#Exercise1">
Exercise 2</A>
</UL></UL>
<HR>
<H2><A NAME="ChapterObjectives"><FONT SIZE=5 COLOR=#FF0000>
Chapter Objectives</FONT></A></H2>
<P>
After you complete this chapter, you should be able to:
<UL>
<LI>Describe the differences between transparent, pooled, and
cluster tables
<LI>Create domains, data elements, and transparent tables in the
Data Dictionary
<LI>Create F1 help for the fields of a table, and create hypertext
links within the F1 help
<LI>Use the four SAP-supplied data browsers to view and modify
data within tables
</UL>
<H2><A NAME="DiscoveringRReleaseLevels"><FONT SIZE=5 COLOR=#FF0000>
Discovering R/3 Release Levels</FONT></A></H2>
<P>
<IMG SRC="../button/newterm.gif" tppabs="http://ebooks.cs.biu.ac.il/0672312174/button/newterm.gif">
<P>
There are many versions-also called <I>release levels</I>-of the
R/3 system in use today. Release 3.0 was the first version, but
since its introduction, SAP has also released versions 3.0a through
3.0f, 3.1g, 3.1h, and 4.0a through 4.0c. You can determine the
release level of your system using the menu path System->Status.
<P>
This book was tested on a 3.0f system. Your system may be on another
release level. Although most of the differences should be minor
with regard to the topics covered here, some differences may cause
confusion or cause the information in this book to appear incorrect.
For example, menu paths can change between release levels. Wherever
possible, differences that may cause confusion have been noted
in this text. However, if the functionality in your system appears
to differ from that described here, you can consult the R/3 release
notes, available online, to determine if the difference can be
attributed to the release level. To access the release notes,
use the following procedure:
<P>
<img src="../button/screencam.gif" tppabs="http://ebooks.cs.biu.ac.il/0672312174/button/screencam.gif">
<P>
Start the ScreenCam "How to Display R/3 Release Notes"
now.
<P>
To display the R/3 release notes:
<OL>
<LI>Go to the main menu and choose the menu path Tools->Find->Search
Interface. The Search Interface: Request screen appears.
<LI>Choose the radio button RELN.
<LI>Press the Choose button on the Application toolbar. The Find
Release Notes screen is displayed.
<LI>Press the Complete List button. The Display Structure: Complete
List of Release Notes screen is displayed.
<LI>Click on any + (plus sign) to expand the node. Modifications
To ABAP will appear under the Basis node, under the sub-node ABAP/4
Development Workbench.
</OL>
<H2><A NAME="DelvingDeeperintotheRDataDictionary"><FONT SIZE=5 COLOR=#FF0000>
Delving Deeper into the R/3 Data Dictionary</FONT></A></H2>
<P>
As a review, please take a few minutes and re-read the section
in Day 2 titled "Introducing the R/3 Data Dictionary"
at this time.
<P>
Data Dictionary objects are used in most ABAP/4 programs. The
interlocking nature of ABAP/4 programs and DDIC objects makes
in-depth knowledge of the R/3 Data Dictionary an essential programming
skill. Therefore, beginning with this chapter, you will learn
how to create DDIC objects such as tables, data elements, and
domains.<P>
<CENTER>
<TABLE BORDERCOLOR=#000000 BORDER=1>
<TR VALIGN=TOP><TD WIDTH=600><B>NOTE</B></TD></TR>
<TR VALIGN=TOP><TD WIDTH=600>
<BLOCKQUOTE>
Many development objects used as examples throughout this book (such as tables, domains, and data elements) are based on actual development objects in the R/3 system. The example objects will have the same name as the actual R/3 objects, but they will be prefixed with <TT>ztx</TT>. For example, <TT>lfa1 </TT>is a real table in R/3, and the example table in this book is <TT>ztxlfa1</TT>.
</BLOCKQUOTE>
</TD></TR>
</TABLE>
</CENTER>
<P>
<H2><A NAME="ExploringtheTypesofTablesinR"><FONT SIZE=5 COLOR=#FF0000>
Exploring the Types of Tables in R/3</FONT></A></H2>
<P>
In R/3 there are three table types: transparent tables<I>, </I>pooled
tables<I>,</I> and cluster tables. They are shown in Figure 3.1.
<P>
<A HREF="javascript:popUp('f3-1.gif')"><B>Figure 3.1 : </B><I>The three table types in the R/3 Data Dictionary</I>.</A>
<H3><A NAME="TransparentTables">
Transparent Tables</A></H3>
<P>
<IMG SRC="../button/newterm.gif" tppabs="http://ebooks.cs.biu.ac.il/0672312174/button/newterm.gif">
<P>
A transparent table in the dictionary has a one-to-one relationship
with a table in the database. Its structure in R/3 Data Dictionary
corresponds to a single database table. For each transparent table
definition in the dictionary, there is one associated table in
the database. The database table has the same name, the same number
of fields, and the fields have the same names as the R/3 table
definition. When looking at the definition of an R/3 transparent
table, it might seem like you are looking at the database table
itself.
<P>
<IMG SRC="../button/newterm.gif" tppabs="http://ebooks.cs.biu.ac.il/0672312174/button/newterm.gif">
<P>
Transparent tables are much more common than pooled or cluster
tables. They are used to hold <I>application data</I>. Application
data is the master data or transaction data used by an application.
An example of master data is the table of vendors (called vendor
master data), or the table of customers (called customer master
data). An example of transaction data is the orders placed by
the customers, or the orders sent to the vendors.
<P>
Transparent tables are probably the only type of table you will
ever create. Pooled and cluster tables are not usually used to
hold application data but instead hold system data, such as system
configuration information, or historical and statistical data.
<P>
Both pooled and cluster tables have many-to-one relationships
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