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<A NAME="CHILD_LINKS"><strong>Subsections</strong></A>
<UL>
<LI><A NAME="tex2html894"
 HREF="usersguidenode6.html#SECTION00610000000000000000">4.1 The classic Entity-Relationship Diagram Editor (TERD)</A>
<UL>
<LI><A NAME="tex2html895"
 HREF="usersguidenode6.html#SECTION00611000000000000000">4.1.1 Nodes and Edges</A>
<LI><A NAME="tex2html896"
 HREF="usersguidenode6.html#SECTION00612000000000000000">4.1.2 Cardinality Constraints and Role Names</A>
<LI><A NAME="tex2html897"
 HREF="usersguidenode6.html#SECTION00613000000000000000">4.1.3 Taxonomic Structures</A>
<LI><A NAME="tex2html898"
 HREF="usersguidenode6.html#SECTION00614000000000000000">4.1.4 Constraint Checking</A>
</UL>
<LI><A NAME="tex2html899"
 HREF="usersguidenode6.html#SECTION00620000000000000000">4.2 The Entity-Relationship Diagram Editor (TESD)</A>
<UL>
<LI><A NAME="tex2html900"
 HREF="usersguidenode6.html#SECTION00621000000000000000">4.2.1 Nodes and Edges</A>
<LI><A NAME="tex2html901"
 HREF="usersguidenode6.html#SECTION00622000000000000000">4.2.2 Cardinality Constraints</A>
<LI><A NAME="tex2html902"
 HREF="usersguidenode6.html#SECTION00623000000000000000">4.2.3 Read direction arrows</A>
<LI><A NAME="tex2html903"
 HREF="usersguidenode6.html#SECTION00624000000000000000">4.2.4 Taxonomic Structures</A>
<LI><A NAME="tex2html904"
 HREF="usersguidenode6.html#SECTION00625000000000000000">4.2.5 Constraint Checking</A>
</UL>
<LI><A NAME="tex2html905"
 HREF="usersguidenode6.html#SECTION00630000000000000000">4.3 The Class-Relationship Diagram Editor (TCRD)</A>
<UL>
<LI><A NAME="tex2html906"
 HREF="usersguidenode6.html#SECTION00631000000000000000">4.3.1 Nodes and Edges</A>
<LI><A NAME="tex2html907"
 HREF="usersguidenode6.html#SECTION00632000000000000000">4.3.2 Classes and Relationships</A>
<LI><A NAME="tex2html908"
 HREF="usersguidenode6.html#SECTION00633000000000000000">4.3.3 Attributes and Operations</A>
<LI><A NAME="tex2html909"
 HREF="usersguidenode6.html#SECTION00634000000000000000">4.3.4 Taxonomic Structures</A>
<LI><A NAME="tex2html910"
 HREF="usersguidenode6.html#SECTION00635000000000000000">4.3.5 Constraint Checking</A>
</UL>
<LI><A NAME="tex2html911"
 HREF="usersguidenode6.html#SECTION00640000000000000000">4.4 The Static Structure Diagram Editor (TSSD)</A>
<UL>
<LI><A NAME="tex2html912"
 HREF="usersguidenode6.html#SECTION00641000000000000000">4.4.1 Nodes and Edges</A>
<LI><A NAME="tex2html913"
 HREF="usersguidenode6.html#SECTION00642000000000000000">4.4.2 N-ary Associations</A>
<LI><A NAME="tex2html914"
 HREF="usersguidenode6.html#SECTION00643000000000000000">4.4.3 Objects</A>
<LI><A NAME="tex2html915"
 HREF="usersguidenode6.html#SECTION00644000000000000000">4.4.4 Taxonomic Structures</A>
<LI><A NAME="tex2html916"
 HREF="usersguidenode6.html#SECTION00645000000000000000">4.4.5 Constraint Checking</A>
</UL></UL>
<!--End of Table of Child-Links-->
<HR>

<H1><A NAME="SECTION00600000000000000000">&#160;</A> <A NAME="DataViewEditing">&#160;</A><A NAME="4089">&#160;</A>
<BR>
4. Data View Editors
</H1>

<P>
Data view editors manipulate diagrams commonly used for data modeling.
This includes various entity-relationship as well as class 
diagram editors. They are described in a particular order in this chapter because 
this is the way TCM, and hence the user interface, is built up :
TSSD specializes TCRD, which specializes TESD, 
which specializes TERD, the oldest of the lot.
Each section may therefore refer to a previous section 
in this chapter.

<P>

<H1><A NAME="SECTION00610000000000000000">&#160;</A>
<A NAME="4091">&#160;</A><A NAME="4092">&#160;</A> 
<A NAME="4093">&#160;</A>
<BR>
4.1 The classic Entity-Relationship Diagram Editor (TERD)
</H1>

<P>
This editor manipulates ER diagrams with the syntax defined 
in&nbsp;[<A
 HREF="usersguidenode14.html#Wieringa96-01">22</A>].

<P>

<H2><A NAME="SECTION00611000000000000000">
4.1.1 Nodes and Edges</A>
</H2>

<P>
See figure&nbsp;<A HREF="usersguidenode6.html#ERRepresentations">4.1</A> for the subjects
and the representing shapes that are used in TERD.
In figure&nbsp;<A HREF="usersguidenode6.html#ERConnections">4.2</A> you can see which node types
can be connected by which edge types.
The constraints of which node types can be connected by which
edge types are immediately enforced.
Note that function edges can be represented by two shape types, uni-directional
(single) arrows and bidirectional (double) arrows. The latter denotes 
a one-one relationship. So, in figure&nbsp;<A HREF="usersguidenode6.html#ERConnections">4.2</A> a single function 
arrow may also be a bidirectional arrow.

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="ERRepresentations">&#160;</A><A NAME="4172">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.1:</STRONG>
Entity-relationship diagram nodes and edges.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">
<TABLE CELLPADDING=3 BORDER="1" ALIGN="CENTER">
<TR><TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/box.eps}$ -->
<IMG
 WIDTH="89" HEIGHT="45" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg32.gif"
 ALT="\includegraphics{p/box.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Entity type<A NAME="4111">&#160;</A></TD>
<TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/ellipse.eps}$ -->
<IMG
 WIDTH="89" HEIGHT="45" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg34.gif"
 ALT="\includegraphics{p/ellipse.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Value type</TD>
</TR>
<TR><TD ALIGN="CENTER"><A NAME="4119">&#160;</A>
<P>
<HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/taxonomyjunction.eps}$ -->
<IMG
 WIDTH="24" HEIGHT="24" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg64.gif"
 ALT="\includegraphics{p/taxonomyjunction.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Taxonomy junction<A NAME="4127">&#160;</A></TD>
<TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/diamond.eps}$ -->
<IMG
 WIDTH="88" HEIGHT="45" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg33.gif"
 ALT="\includegraphics{p/diamond.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Relationship</TD>
</TR>
<TR><TD ALIGN="CENTER"><A NAME="4135">&#160;</A>
<P>
<HR><P></P>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/c2line.eps}$ -->
<IMG
 WIDTH="93" HEIGHT="32" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg65.gif"
 ALT="\includegraphics{p/c2line.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Binary relationship<A NAME="4142">&#160;</A></TD>
<TD ALIGN="CENTER">
<BR><HR><P></P>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/c1arrow.eps}$ -->
<IMG
 WIDTH="93" HEIGHT="31" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg66.gif"
 ALT="\includegraphics{p/c1arrow.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Function</TD>
</TR>
<TR><TD ALIGN="CENTER"><A NAME="4149">&#160;</A>
<P>
<HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/isaarrow.eps}$ -->
<IMG
 WIDTH="93" HEIGHT="20" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg67.gif"
 ALT="\includegraphics{p/isaarrow.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Is-a relationship<A NAME="4156">&#160;</A></TD>
<TD ALIGN="CENTER">
<BR><HR><P></P>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/predefinedline.eps}$ -->
<IMG
 WIDTH="93" HEIGHT="1" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg68.gif"
 ALT="\includegraphics{p/predefinedline.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Empty edge<A NAME="4163">&#160;</A></TD>
</TR>
<TR><TD ALIGN="CENTER"><P>
<HR><P></P>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/doublearrow.eps}$ -->
<IMG
 WIDTH="94" HEIGHT="19" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg61.gif"
 ALT="\includegraphics{p/doublearrow.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>(One-one) Function</TD>
<TD ALIGN="CENTER">&nbsp;</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94><A NAME="4170">&#160;</A></TD>
</TR>
</TABLE></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="ERConnections">&#160;</A><A NAME="4179">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.2:</STRONG>
Permitted Entity-relationship connections.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/ERconnections.eps}$ -->
<IMG
 WIDTH="643" HEIGHT="369" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg69.gif"
 ALT="\includegraphics{p/ERconnections.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>

<H2><A NAME="SECTION00612000000000000000">&#160;</A> <A NAME="CardConstraints">&#160;</A>
<BR>
4.1.2 Cardinality Constraints and Role Names
</H2>

<P>
Most edge types have a name label, which is shown as an <TT>L</TT> in 
figure&nbsp;<A HREF="usersguidenode6.html#ERRepresentations">4.1</A>. The default position of a name label is 
near the center of the middlemost segment of the edge. The middlemost segment
is ``number of segments div 2''. When the label is first edited, the 
default position becomes the center of the segment where the line is 
selected for editing. When the line is not vertical,
the name label is by default positioned at a fixed distance above the line,
preventing that the label goes through the line and becomes unreadable. 
When the line is vertical, the label is positioned slightly to the left 
of the line, preventing that a short label goes through the line and 
becomes unreadable.<A NAME="4187">&#160;</A><A NAME="4188">&#160;</A>
Some edge types like Binary relationships and Functions
also have <B>role names</B> and/or <B>cardinality constraints</B>.
See figure&nbsp;<A HREF="usersguidenode6.html#DefaultPositions">4.3</A> for the default positions of
the roles names (<TT>r1</TT> and <TT>r2</TT>) and cardinality constraints 
(<TT>c1</TT> and <TT>c2</TT>). These labels are editable just like the name 
labels. 
The role name <TT>r1</TT> and the cardinality constraint <TT>c1</TT> 
have their default positions near the middle of the first quarter of the 
first segment of the line. <TT>r2</TT> and <TT>c2</TT> have their default 
positions near the middle of the last quarter of the last segment of the 
line&nbsp;<A NAME="tex2html67"
 HREF="#foot4200"><SUP>4.1</SUP></A>.
When the line is more or less horizontal, role names are positioned 
above the line and when the line is more or less vertical, role names 
are positioned at the left side of the line (just like the name label). 
Cardinality constraint labels are positioned at the side opposing the role
name labels. See figure&nbsp;<A HREF="usersguidenode5.html#PersonExample">3.3</A> for an 
example ER diagram with role names and cardinality constraints.

<P>
Remark: A binary relationship whose c2 cardinality constraint is 1, is
equivalent to a function edge. The difference is that, instead of a 1, 
an arrow head is drawn. Nevertheless, TERD considers them as
separate edge types.

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="DefaultPositions">&#160;</A><A NAME="4205">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.3:</STRONG>
Default label positions of a binary relationship edge.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/defaultpositions.eps}$ -->
<IMG
 WIDTH="214" HEIGHT="81" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg70.gif"
 ALT="\includegraphics{p/defaultpositions.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>
TERD enforces immediately that cardinality constraints conform to the 
BNF syntax of figure&nbsp;<A HREF="usersguidenode6.html#CardSyntax">4.4</A>.
But TERD does not check if subranges are contradictory such as
the constraints <TT>1..0</TT> and <TT>2,&gt;=3</TT>.
<BR>
<DIV ALIGN="CENTER"><A NAME="CardSyntax">&#160;</A><A NAME="4236">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.4:</STRONG>
Cardinality constraint syntax.</CAPTION>
<TR><TD><IMG
 WIDTH="289" HEIGHT="243"
 SRC="usersguideimg71.gif"
 ALT="\begin{figure}
\begin{center}
\begin{math}
\begin{array}{lll}
constraint & \righ...
...rt{\bf 8}\vert{\bf 9} \\ \nonumber
\end{array}\end{math}\end{center}\end{figure}"></TD></TR>
</TABLE>
</DIV>
<BR>
<P>

<H2><A NAME="SECTION00613000000000000000">&#160;</A> <A NAME="TaxonomyConstraints">&#160;</A><A NAME="4242">&#160;</A>
<A NAME="4243">&#160;</A><A NAME="4244">&#160;</A><A NAME="4245">&#160;</A>
<BR>
4.1.3 Taxonomic Structures
</H2> 

<P>
A <B>taxonomic relationship</B> (also called specialization, generalization,
inheritance or is-a hierarchy)<A NAME="4247">&#160;</A> is 
constructed from a taxonomy junction node connected to an entity type
by a single is-a relationship edge and connected to two or more other entity
types by two or more empty edges.
The entity type where the is-a relationship edge ends is the
<B>generalization</B> (or supertype), the other entity types 
are <B>specializations</B> (or subtypes).
See, for example, figure&nbsp;<A HREF="usersguidenode6.html#TaxonomyExample">4.5</A>.
If two entity types are is-a related then a single
is-a relationship arrow can be drawn between them,
but when an entity type is specialized into more than one different
entity type then it is customary to draw one compound is-a relationship
with a taxonomy junction.

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="TaxonomyExample">&#160;</A><A NAME="4255">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.5:</STRONG>
Example taxonomic structure.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/taxonomyexample.eps}$ -->
<IMG
 WIDTH="405" HEIGHT="261" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg72.gif"
 ALT="\includegraphics{p/taxonomyexample.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>
The <B>Show ISA Hierarchy</B> toggle in the View menu of TERD shows
the shapes which constitute the is-a hierarchy. When you turn it on,
the shapes that are not part of the hierarchy are made invisible.
When you turn it off, all shapes are made visible again.
<A NAME="4259">&#160;</A>

<P>
An is-a relationship has a built-in name label "is_a", an 
empty edge does not have a label. Taxonomy junctions should 
have one of the following labels : "", "d", "e" or "de".
A "d" stands for disjunctive and an "e" stands for exhaustive.
These constraints are immediately enforced.

<P>

<H2><A NAME="SECTION00614000000000000000">
4.1.4 Constraint Checking</A>
</H2>

<P>
In addition to the connection constraints, the syntax of cardinality 
constraints and the other graphical conventions that TERD enforces, 
TERD checks a lot of immediately enforced and soft constraints.
These are summarized in figure&nbsp;<A HREF="usersguidenode6.html#ERConstraints">4.6</A>.

<P>
Some of these constraints are enforced immediately during most but not all
editor commands. If that is the case, they are additionally checked by 
Check Diagram as a soft constraint.

<P>
Note that the unique name constraints do not concern duplicate 
node shapes. This is one of the reasons for the existence of 
duplicate shapes, i.e. showing the <I>same</I> node on <I>different</I>
places in the diagram.

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="ERConstraints">&#160;</A><A NAME="4267">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.6:</STRONG>
Immediately checked and soft constraints on ERDs.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/ERconstraints.eps}$ -->
<IMG
 WIDTH="562" HEIGHT="509" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg73.gif"
 ALT="\includegraphics{p/ERconstraints.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>

<H1><A NAME="SECTION00620000000000000000">&#160;</A>
<A NAME="4272">&#160;</A><A NAME="4273">&#160;</A> 
<A NAME="4274">&#160;</A>
<BR>
4.2 The Entity-Relationship Diagram Editor (TESD)
</H1>

<P>
This editor manipulates ER diagrams with the syntax defined 
in&nbsp;[<A
 HREF="usersguidenode14.html#Wieringa99-01">23</A>]. These ER diagrams are a subset of UML Static 
Structure diagrams.

<P>

<H2><A NAME="SECTION00621000000000000000">
4.2.1 Nodes and Edges</A>
</H2>

<P>
See figure&nbsp;<A HREF="usersguidenode6.html#ESRepresentations">4.7</A> for the subjects
and the representing shapes that are used in TESD.
In figure&nbsp;<A HREF="usersguidenode6.html#ESConnections">4.8</A> you can see which node types
can be connected by which edge types.
The constraints of which node types can be connected by which
edge types are immediately enforced.
Note that entity types can be represented by two different
box types. In figure&nbsp;<A HREF="usersguidenode6.html#ESConnections">4.8</A> only the single box
type variant is shown but each single box could be replaced by 
a double box.

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="ESRepresentations">&#160;</A><A NAME="4345">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.7:</STRONG>
Entity-relationship diagram nodes and edges.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">
<TABLE CELLPADDING=3 BORDER="1" ALIGN="CENTER">
<TR><TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/box.eps}$ -->
<IMG
 WIDTH="89" HEIGHT="45" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg32.gif"
 ALT="\includegraphics{p/box.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Entity type<A NAME="4292">&#160;</A></TD>
<TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/diamond.eps}$ -->
<IMG
 WIDTH="88" HEIGHT="45" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg33.gif"
 ALT="\includegraphics{p/diamond.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Relationship <A NAME="4300">&#160;</A></TD>
</TR>
<TR><TD ALIGN="CENTER"><P>
<HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/doublebox.eps}$ -->
<IMG
 WIDTH="89" HEIGHT="76" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg74.gif"
 ALT="\includegraphics{p/doublebox.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Entity type</TD>
<TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/UMLtaxonomyjunction.eps}$ -->
<IMG
 WIDTH="24" HEIGHT="24" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg75.gif"
 ALT="\includegraphics{p/UMLtaxonomyjunction.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Generalization junction<A NAME="4315">&#160;</A></TD>
</TR>
<TR><TD ALIGN="CENTER"><P>
<HR><P></P>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/c2line.eps}$ -->
<IMG
 WIDTH="93" HEIGHT="32" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg65.gif"
 ALT="\includegraphics{p/c2line.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Binary relationship<A NAME="4322">&#160;</A></TD>
<TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/dashedline.eps}$ -->
<IMG
 WIDTH="94" HEIGHT="15" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg76.gif"
 ALT="\includegraphics{p/dashedline.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Association entity type link
<A NAME="4329">&#160;</A></TD>
</TR>
<TR><TD ALIGN="CENTER"><P>
<HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/rcline.eps}$ -->
<IMG
 WIDTH="93" HEIGHT="30" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg77.gif"
 ALT="\includegraphics{p/rcline.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Participant link (in N-ary relationship)
<A NAME="4336">&#160;</A></TD>
<TD ALIGN="CENTER">
<BR><HR><P></P>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/generalizationarrow.eps}$ -->
<IMG
 WIDTH="92" HEIGHT="25" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg62.gif"
 ALT="\includegraphics{p/generalizationarrow.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Generalization <A NAME="4343">&#160;</A></TD>
</TR>
<TR><TD ALIGN="CENTER"><P></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>&nbsp;</TD>
<TD ALIGN="CENTER">&nbsp;</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>&nbsp;</TD>
</TR>
</TABLE></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="ESConnections">&#160;</A><A NAME="4352">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.8:</STRONG>
Permitted Entity-relationship connections.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/ESconnections.eps}$ -->
<IMG
 WIDTH="643" HEIGHT="320" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg78.gif"
 ALT="\includegraphics{p/ESconnections.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>

<H2><A NAME="SECTION00622000000000000000">&#160;</A> <A NAME="ESCardConstraints">&#160;</A>
<BR>
4.2.2 Cardinality Constraints
</H2>

<P>
TESD enforces immediately that cardinality constraints conform to the 
BNF syntax of figure&nbsp;<A HREF="usersguidenode6.html#ESDCardSyntax">4.9</A>.
TESD does not check if subranges are contradictory such as
the constraints <TT>1..0</TT> and <TT>2,3..*</TT>.
Mind that the syntax differs from the syntax in TERD 
(figure&nbsp;<A HREF="usersguidenode6.html#CardSyntax">4.4</A>).

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="ESDCardSyntax">&#160;</A><A NAME="4384">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.9:</STRONG>
ESD Cardinality constraint syntax.</CAPTION>
<TR><TD><IMG
 WIDTH="289" HEIGHT="239"
 SRC="usersguideimg79.gif"
 ALT="\begin{figure}
\begin{center}
\begin{math}
\begin{array}{lll}
constraint & \righ...
...r&\rightarrow&{\bf *} \\ \nonumber
\end{array}\end{math}\end{center}\end{figure}"></TD></TR>
</TABLE>
</DIV>
<BR>
<P>

<H2><A NAME="SECTION00623000000000000000">&#160;</A> <A NAME="ReadDirectionArrows">&#160;</A>
<BR>
4.2.3 Read direction arrows
</H2>

<P>
Binary relationships in TESD (and TSSD) can optionally have a read direction arrow
<A NAME="4390">&#160;</A>connected to the name label. This arrow is a clue for the user for 
how to read the label. It has no semantics. Via the submenu called ``Change Read Direction'' in the 
Edit menu a read direction arrow can be added or removed. The option ``None'' removes the arrow
from all selected binary relationships. The option ``From Shape'' shows an arrow directed to
the ``from''-shape, i.e.` the shape from which the relationship line originates when it was
drawn. The option ``To Shape'' shows an arrow directed to the ``to''-shape. 
Or simply just click on the 'read direction area' behind the name label to switch between 
the three options 'To Shape', 'From Shape' and 'None'.

<P>

<H2><A NAME="SECTION00624000000000000000">&#160;</A> <A NAME="ESDTaxonomyConstraints">&#160;</A><A NAME="4393">&#160;</A>
<A NAME="4394">&#160;</A><A NAME="4395">&#160;</A><A NAME="4396">&#160;</A>
<BR>
4.2.4 Taxonomic Structures
</H2> 

<P>
The is-a relationship in TERD is called generalization in TESD, being
represented by a open arrow.

<P>
A <B>taxonomic relationship</B> consists of a taxonomy or generalization
node connected to three or more entity types by generalization edges.
On connecting a generalization edge from an entity type to a 
generalization node, the open arrow end will disappear, resulting in 
an empty edge representation. See, for example, 
figure&nbsp;<A HREF="usersguidenode6.html#ESDTaxonomyExample">4.10</A>.

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="ESDTaxonomyExample">&#160;</A><A NAME="4403">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.10:</STRONG>
ESD Example taxonomic structure.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/ESDtaxonomyexample.eps}$ -->
<IMG
 WIDTH="378" HEIGHT="265" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg80.gif"
 ALT="\includegraphics{p/ESDtaxonomyexample.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>
The <B>Show ISA Hierarchy</B> toggle in the View menu of TESD shows
the shapes which constitute the is-a hierarchy. When you turn it on,
the shapes that are not part of the hierarchy are made invisible.
When you turn it off, all shapes are made visible again.<A NAME="4407">&#160;</A>

<P>
An is-a relationship can have a label name, with the exception of a 
generalization arrow leading towards a generalization node which can not 
have a label. Generalization nodes should 
have one of the following labels : "", "d", "c", "dc" or "cd".
A "d" stands for disjunctive and a "c" stands for complementary.
These constraints are immediately enforced.

<P>

<H2><A NAME="SECTION00625000000000000000">
4.2.5 Constraint Checking</A>
</H2>

<P>
TESD checks also the soft and immediately enforced constraints that are
summarized in figure&nbsp;<A HREF="usersguidenode6.html#ESConstraints">4.11</A>.

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="ESConstraints">&#160;</A><A NAME="4413">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.11:</STRONG>
Immediately checked and soft constraints on ERDs.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/ESconstraints.eps}$ -->
<IMG
 WIDTH="547" HEIGHT="395" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg81.gif"
 ALT="\includegraphics{p/ESconstraints.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>

<H1><A NAME="SECTION00630000000000000000">&#160;</A>
<A NAME="4418">&#160;</A><A NAME="4419">&#160;</A> 
<A NAME="4420">&#160;</A>
<BR>
4.3 The Class-Relationship Diagram Editor (TCRD)
</H1>

<P>

<H2><A NAME="SECTION00631000000000000000">
4.3.1 Nodes and Edges</A>
</H2>

<P>
See figure&nbsp;<A HREF="usersguidenode6.html#CRRepresentations">4.12</A> for the subjects
and the representing shapes that are used in TCRD.
In figure&nbsp;<A HREF="usersguidenode6.html#CRConnections">4.13</A> you can see which node types
can be connected by which edge types. These are immediately 
enforced constraints.
Note that classes can be represented by three different
box types. In figure&nbsp;<A HREF="usersguidenode6.html#CRConnections">4.13</A> only the double box
type variant is shown but each double box could be 
replaced by a single or triple box.

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="CRRepresentations">&#160;</A><A NAME="4511">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.12:</STRONG>
Class-relationship diagram nodes and edges.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">
<TABLE CELLPADDING=3 BORDER="1" ALIGN="CENTER">
<TR><TD ALIGN="CENTER">
<BR><HR><P></P>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/box.eps}$ -->
<IMG
 WIDTH="89" HEIGHT="45" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg32.gif"
 ALT="\includegraphics{p/box.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Class</TD>
<TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/triplebox.eps}$ -->
<IMG
 WIDTH="89" HEIGHT="121" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg82.gif"
 ALT="\includegraphics{p/triplebox.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Class</TD>
</TR>
<TR><TD ALIGN="CENTER"><P>
<HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/doublebox.eps}$ -->
<IMG
 WIDTH="89" HEIGHT="76" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg74.gif"
 ALT="\includegraphics{p/doublebox.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Class<A NAME="4451">&#160;</A></TD>
<TD ALIGN="CENTER">&nbsp;</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>&nbsp;</TD>
</TR>
<TR><TD ALIGN="CENTER"><P>
<HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/taxonomyjunction.eps}$ -->
<IMG
 WIDTH="24" HEIGHT="24" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg64.gif"
 ALT="\includegraphics{p/taxonomyjunction.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Taxonomy junction<A NAME="4459">&#160;</A></TD>
<TD ALIGN="CENTER">
<BR><HR><P></P>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/modejunction.eps}$ -->
<IMG
 WIDTH="24" HEIGHT="24" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg83.gif"
 ALT="\includegraphics{p/modejunction.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Mode junction<A NAME="4467">&#160;</A></TD>
</TR>
<TR><TD ALIGN="CENTER"><P>
<HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/c2line.eps}$ -->
<IMG
 WIDTH="93" HEIGHT="32" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg65.gif"
 ALT="\includegraphics{p/c2line.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Binary relationship<A NAME="4474">&#160;</A></TD>
<TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/c1arrow.eps}$ -->
<IMG
 WIDTH="93" HEIGHT="31" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg66.gif"
 ALT="\includegraphics{p/c1arrow.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Function<A NAME="4481">&#160;</A></TD>
</TR>
<TR><TD ALIGN="CENTER"><P>
<HR><P></P>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/dashedc1arrow.eps}$ -->
<IMG
 WIDTH="93" HEIGHT="31" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg84.gif"
 ALT="\includegraphics{p/dashedc1arrow.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Component function<A NAME="4488">&#160;</A></TD>
<TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/isaarrow.eps}$ -->
<IMG
 WIDTH="93" HEIGHT="20" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg67.gif"
 ALT="\includegraphics{p/isaarrow.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Is-a relationship<A NAME="4495">&#160;</A></TD>
</TR>
<TR><TD ALIGN="CENTER"><P>
<HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/predefinedline.eps}$ -->
<IMG
 WIDTH="93" HEIGHT="1" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg68.gif"
 ALT="\includegraphics{p/predefinedline.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Empty edge <A NAME="4502">&#160;</A></TD>
<TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/oneonefunction.eps}$ -->
<IMG
 WIDTH="92" HEIGHT="20" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg85.gif"
 ALT="\includegraphics{p/oneonefunction.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>(One-one) function<A NAME="4509">&#160;</A></TD>
</TR>
<TR><TD ALIGN="CENTER"><P></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>&nbsp;</TD>
<TD ALIGN="CENTER">&nbsp;</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>&nbsp;</TD>
</TR>
</TABLE></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="CRConnections">&#160;</A><A NAME="4518">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.13:</STRONG>
Permitted Class-relationship connections.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/CRconnections.eps}$ -->
<IMG
 WIDTH="666" HEIGHT="340" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg86.gif"
 ALT="\includegraphics{p/CRconnections.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>

<H2><A NAME="SECTION00632000000000000000">
4.3.2 Classes and Relationships</A>
</H2>

<P>
The class node type of TCRD can be seen as an extension
of the entity type node type of TERD. Like TERD, TCRD has binary 
relationships and functions. Value type nodes are not needed in TCRD 
because attribute names and value types are now included in the 
class in the form of attribute definitions. Also unlike TERD, TCRD 
does not have a separate node type for relationships. 
Relationship nodes can be<A NAME="4523">&#160;</A><A NAME="4524">&#160;</A>
represented by the same type of class box. 
The only difference between a
real class instance and a relationship instance, 
is that the latter has two or 
<A NAME="4525">&#160;</A><A NAME="4526">&#160;</A>more <B>components</B>. 
A relationship instance is called a <B>link</B>. 
The components make up the identity of a link. The components of 
a link are classes or other links.
The component relationship is a projection function represented
by a dashed arrow. This 
function is called a <B>component function</B>.<A NAME="4530">&#160;</A><A NAME="4531">&#160;</A>
Like ordinary functions, component functions can have a cardinality
constraint label (see figure&nbsp;<A HREF="usersguidenode6.html#ComponentExample">4.14</A>).
There is no other visual difference between a class instance
and a relationship instance in TCRD than the component functions.
So, in TCRD a link can have attributes, operations and it can be part 
of a taxonomic structure. 

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="ComponentExample">&#160;</A><A NAME="4536">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.14:</STRONG>
Example CR diagram, showing a relationship class.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/componentexample.eps}$ -->
<IMG
 WIDTH="503" HEIGHT="43" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg87.gif"
 ALT="\includegraphics{p/componentexample.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>
TCRD inherits all the applicable constraints of TERD,
on the understanding that classes in TCRD replace
the entity types from TERD.
Furthermore, see section&nbsp;<A HREF="usersguidenode6.html#CardConstraints">4.1.2</A> for the use 
of cardinality constraints and role names,
see section&nbsp;<A HREF="usersguidenode6.html#TaxonomyConstraints">4.1.3</A> for the use of 
taxonomies and see figure&nbsp;<A HREF="usersguidenode6.html#ERConstraints">4.6</A>
for all the other constraints that are checked in TERD.

<P>

<H2><A NAME="SECTION00633000000000000000">&#160;</A> <A NAME="TCRDAttributes">&#160;</A><A NAME="4545">&#160;</A><A NAME="4546">&#160;</A>
<BR>
4.3.3 Attributes and Operations
</H2> 
The class-relationship editor TCRD offers
classes that can have a number of <B>attributes</B> 
and a number of <B>operations</B>&nbsp;<A NAME="tex2html79"
 HREF="#foot4778"><SUP>4.2</SUP></A>.
See figure&nbsp;<A HREF="usersguidenode6.html#ClassExample">4.15</A> for an example. 

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="ClassExample">&#160;</A><A NAME="4557">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.15:</STRONG>
Example class with attribute and operation definitions.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/classexample.eps}$ -->
<IMG
 WIDTH="119" HEIGHT="214" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg88.gif"
 ALT="\includegraphics{p/classexample.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>
A class can be represented by a single box in which only the
name label is visible, by a double box<A NAME="4560">&#160;</A> in which the 
name label and all the attributes are visible, or by a triple box
<A NAME="4561">&#160;</A> in which the name label, all the attributes and 
all the operations are visible.
For each representing shape type there is
a separate tiled button in the list of nodes in the main window,
but they are all representations of the same node type, Class.
You can change the representation of an existing class by 
the <B>change box type</B><A NAME="4563">&#160;</A><A NAME="4564">&#160;</A> 
command in a submenu of the Edit menu. 
These commands modify only the shapes of the selected boxes.
The other shapes, unselected boxes and shapes that are not boxes, 
are not updated. These commands only change the shape; the attributes
and operations are preserved.

<P>
Each attribute definition and each operation definition occupies a 
<I>single</I> text line.
Any text on a single line in the appropriate part of a box is 
considered as an attribute or operation definition.
Attribute names are in the second compartment and operation names 
are in the third compartment of the class box.
You can perform the following operations on attributes and operations:
<UL>
<LI><B>Append one or more attributes or operations</B>.
To add attributes or operations to the end of the attributes
or operations list of a class, click the mouse pointer in the
empty part at the bottom of the compartment in the class box 
and start editing. You can add more than one attribute or operation 
at a time by separating them by newlines. When you stop editing and
the autoresize is on, the 
size of the class box is adjusted to the width and the height of 
the new list of attributes and operations and the new attributes 
and operations in the box are always left adjusted.
<LI><B>Insert one or more attributes or operations</B>. To insert 
new attributes or
operations somewhere in the current attribute or operation list, click 
the text line that should precede them and go into edit mode. 
First enter a newline and then add the new attributes or operations 
like described above.
<LI><B>Update an attribute or operation</B>. To update an existing 
attribute or operation, click its text line and edit it.
<LI><B>Remove an attribute or operation</B>. To remove an existing 
attribute or operation, click its text line for editing and delete 
the text with &lt;Escape&gt; (in-line editor) or do a delete
all in the out-line editor.
If you stop editing, the attribute or operation is deleted and the 
size of the class box is adjusted.
</UL>
<P>

<H2><A NAME="SECTION00634000000000000000">&#160;</A><A NAME="4574">&#160;</A>
<BR>
4.3.4 Taxonomic Structures
</H2> 
Like TERD, TCRD has taxonomic structures with taxonomy junctions, 
is-a relationships and empty edges.
TCRD offers a second kind of taxonomy junction which is called
<B>mode junction</B> and which is represented by a small dashed circle instead
of a small solid circle.<A NAME="4576">&#160;</A><A NAME="4577">&#160;</A>
Mode junctions are used for constructing <B>mode specializations</B>. 
For an example mode specialization, see figure&nbsp;<A HREF="usersguidenode6.html#ModeExample">4.16</A>.
The concept of mode specialization as a form of type migration is explained 
in appendix&nbsp;<A HREF="usersguidenode11.html#MiniTut">A</A>.
Except the different shape of the circle, mode specializations are drawn in
the same way as static specializations, having the same constraints
as in section&nbsp;<A HREF="usersguidenode6.html#TaxonomyConstraints">4.1.3</A>.

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="ModeExample">&#160;</A><A NAME="4586">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.16:</STRONG>
Example mode specialization.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/modeexample.eps}$ -->
<IMG
 WIDTH="367" HEIGHT="223" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg89.gif"
 ALT="\includegraphics{p/modeexample.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>
An is-a relationship (without a junction) between two classes,
and an is-a relationship connected to a taxonomy junction are considered
as <B>static specializations</B>, whereas is-a relationships connected to 
a mode junctions are considered 
as <B>dynamic specializations</B>.<A NAME="4591">&#160;</A><A NAME="4592">&#160;</A>
Both kinds of specializations can be combined, with the exception that a 
mode type should not be specialized statically.
This is an immediately enforced constraint.

<P>

<H2><A NAME="SECTION00635000000000000000">
4.3.5 Constraint Checking</A>
</H2>

<P>
TCRD checks also the soft and immediately enforced constraints that are
summarized in figure&nbsp;<A HREF="usersguidenode6.html#CRConstraints">4.17</A>.
Note that TCRD checks a lot of constraints but it does not check yet
all plausible constraints on CRDs. 
For instance, name conflicts between operations and attributes of classes 
that are is-a related are not yet discovered and the syntax of 
attributes and operations is still very liberal.

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="CRConstraints">&#160;</A><A NAME="4598">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.17:</STRONG>
Immediately checked and soft constraints on CRDs.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/CRconstraints.eps}$ -->
<IMG
 WIDTH="544" HEIGHT="609" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg90.gif"
 ALT="\includegraphics{p/CRconstraints.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>

<H1><A NAME="SECTION00640000000000000000">&#160;</A>
<A NAME="4603">&#160;</A><A NAME="4604">&#160;</A> 
<A NAME="4605">&#160;</A>
<BR>
4.4 The Static Structure Diagram Editor (TSSD)
</H1>

<P>

<H2><A NAME="SECTION00641000000000000000">
4.4.1 Nodes and Edges</A>
</H2>

<P>
See figure&nbsp;<A HREF="usersguidenode6.html#SSDRepresentations">4.18</A> for the subjects
and the representing shapes that are used in TSSD.
In figure&nbsp;<A HREF="usersguidenode6.html#SSDConnections">4.19</A> you can see which node types
can be connected by which edge types. These are immediately 
enforced constraints.
Note that classes can be represented by three different 
box types, whereas objects can be represented by two different
box types.
In figure&nbsp;<A HREF="usersguidenode6.html#SSDConnections">4.19</A> for classes only the double box
type variant is shown but each double box could be 
replaced by a single or triple box. For objects only the single
box variant is shown but each single box could be replaced by
a double box.

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="SSDRepresentations">&#160;</A><A NAME="4725">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.18:</STRONG>
Static structure diagram nodes and edges.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">
<TABLE CELLPADDING=3 BORDER="1" ALIGN="CENTER">
<TR><TD ALIGN="CENTER"><P>
<HR><P></P>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/box.eps}$ -->
<IMG
 WIDTH="89" HEIGHT="45" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg32.gif"
 ALT="\includegraphics{p/box.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Class <A NAME="4622">&#160;</A></TD>
<TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/objbox.eps}$ -->
<IMG
 WIDTH="88" HEIGHT="44" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg91.gif"
 ALT="\includegraphics{p/objbox.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Object <A NAME="4630">&#160;</A></TD>
</TR>
<TR><TD ALIGN="CENTER"><P>
<HR><P></P>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/doublebox.eps}$ -->
<IMG
 WIDTH="89" HEIGHT="76" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg74.gif"
 ALT="\includegraphics{p/doublebox.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Class</TD>
<TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/objdoublebox.eps}$ -->
<IMG
 WIDTH="88" HEIGHT="70" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg92.gif"
 ALT="\includegraphics{p/objdoublebox.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Object</TD>
</TR>
<TR><TD ALIGN="CENTER"><P>
<HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/triplebox.eps}$ -->
<IMG
 WIDTH="89" HEIGHT="121" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg82.gif"
 ALT="\includegraphics{p/triplebox.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Class</TD>
<TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/diamond.eps}$ -->
<IMG
 WIDTH="88" HEIGHT="45" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg33.gif"
 ALT="\includegraphics{p/diamond.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>N-ary association <A NAME="4659">&#160;</A></TD>
</TR>
<TR><TD ALIGN="CENTER"><P>
<HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/UMLtaxonomyjunction.eps}$ -->
<IMG
 WIDTH="24" HEIGHT="24" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg75.gif"
 ALT="\includegraphics{p/UMLtaxonomyjunction.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Generalization node (extension to UML)</TD>
<TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/aggregationjunction.eps}$ -->
<IMG
 WIDTH="12" HEIGHT="11" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg93.gif"
 ALT="\includegraphics{p/aggregationjunction.eps}">
<BR> </DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Aggregation node (extension to UML) <A NAME="4674">&#160;</A></TD>
</TR>
<TR><TD ALIGN="CENTER"><P>
<HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/c2line.eps}$ -->
<IMG
 WIDTH="93" HEIGHT="32" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg65.gif"
 ALT="\includegraphics{p/c2line.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Binary association<A NAME="4681">&#160;</A></TD>
<TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/objectlink.eps}$ -->
<IMG
 WIDTH="93" HEIGHT="17" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg94.gif"
 ALT="\includegraphics{p/objectlink.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Object link<A NAME="4688">&#160;</A></TD>
</TR>
<TR><TD ALIGN="CENTER"><P>
<HR><P></P>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/generalizationarrow.eps}$ -->
<IMG
 WIDTH="92" HEIGHT="25" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg62.gif"
 ALT="\includegraphics{p/generalizationarrow.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Generalization <A NAME="4695">&#160;</A></TD>
<TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/dashedline.eps}$ -->
<IMG
 WIDTH="94" HEIGHT="15" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg76.gif"
 ALT="\includegraphics{p/dashedline.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Association link<A NAME="4702">&#160;</A></TD>
</TR>
<TR><TD ALIGN="CENTER"><P>
<HR><P></P>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/aggregation.eps}$ -->
<IMG
 WIDTH="92" HEIGHT="17" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg95.gif"
 ALT="\includegraphics{p/aggregation.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Aggregation <A NAME="4709">&#160;</A></TD>
<TD ALIGN="CENTER">
<BR><HR><P></P> 
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/composition.eps}$ -->
<IMG
 WIDTH="92" HEIGHT="17" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg96.gif"
 ALT="\includegraphics{p/composition.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Composition <A NAME="4716">&#160;</A></TD>
</TR>
<TR><TD ALIGN="CENTER"><P>
<HR><P></P>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/rcline.eps}$ -->
<IMG
 WIDTH="93" HEIGHT="30" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg77.gif"
 ALT="\includegraphics{p/rcline.eps}"></DIV>
<BR><HR>
<BR></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>Participant Link</TD>
<TD ALIGN="CENTER">&nbsp;</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94><A NAME="4723">&#160;</A></TD>
</TR>
<TR><TD ALIGN="CENTER"><P></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>&nbsp;</TD>
<TD ALIGN="CENTER">&nbsp;</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=94>&nbsp;</TD>
</TR>
</TABLE></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="SSDConnections">&#160;</A><A NAME="4732">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.19:</STRONG>
Permitted Static structure connections.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/SSDconnections.eps}$ -->
<IMG
 WIDTH="643" HEIGHT="623" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg97.gif"
 ALT="\includegraphics{p/SSDconnections.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>

<H2><A NAME="SECTION00642000000000000000">
4.4.2 N-ary Associations</A>
</H2>

<P>
TSSD inherits all the applicable constraints of TESD.
TSSD also supports N-ary associations,
being represented by a diamond node shape, connecting the associated
classes or objects.
See figure&nbsp;<A HREF="usersguidenode6.html#N-ary-association">4.20</A>.

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="N-ary-association">&#160;</A><A NAME="4741">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.20:</STRONG>
Example of a n-ary association.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/n-ary-association2.eps}$ -->
<IMG
 WIDTH="574" HEIGHT="183" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg98.gif"
 ALT="\includegraphics{p/n-ary-association2.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>

<H2><A NAME="SECTION00643000000000000000">&#160;</A> <A NAME="4746">&#160;</A>
<BR>
4.4.3 Objects
</H2>
In addition to classes, objects can be specified. 
An object is an instance of a class, which can be represented by the same
type of class box with the name of the instance being underlined.
Objects can be represented by two different box types : single boxes 
where only the name label is visible, or double boxes in which the 
name label and all the attributes are visible.
The top compartment contains the object and class name in the form of
<B><U>objectname:classname</U></B>.
The bottom compartment may list the attribute names and values.
Operations are not shown in objects, because they are all the same for
all objects of a class.
See figure&nbsp;<A HREF="usersguidenode6.html#SSDObjectNotations">4.21</A> for permitted object notations.
Object nodes can be connected to other objects by means of an 
object link edge. Use a participant link to connect an object to a 
n-ary relationship node.

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="SSDObjectNotations">&#160;</A><A NAME="4752">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.21:</STRONG>
Example Object notations.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/SSDobjects.eps}$ -->
<IMG
 WIDTH="598" HEIGHT="92" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg99.gif"
 ALT="\includegraphics{p/SSDobjects.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>

<H2><A NAME="SECTION00644000000000000000">&#160;</A><A NAME="4757">&#160;</A>
<BR>
4.4.4 Taxonomic Structures
</H2> 
In addition to UML, TSSD supports taxonomic structures using 
generalization and aggregation nodes.
A generalization node is being represented by a small circle.
Classes may be connected to a generalization node using the
generalization edges.
Like TESD, generalization nodes may have a label.
The following labels are permitted : "", "d", "c", "dc" or "cd".
A "d" stands for disjunctive and a "c" stands for complementary.
These constraints are immediately enforced.
The open arrow of the generalization arrow will disappear on 
connecting it from a class box to a generalization node; an empty edge
will be shown instead.

<P>
An aggregation node is being represented by a small black circle.
Classes may be connected to an aggregation node using the 
aggregation or composition edges.
The open diamond of the aggregation arrow and the black diamond of
the composition arrow will disappear on connecting it from a class box to 
an aggregation node; an empty edge will be shown instead.
See figure&nbsp;<A HREF="usersguidenode6.html#SSDtaxonomic">4.22</A> for some permitted notations.

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="SSDtaxonomic">&#160;</A><A NAME="4762">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.22:</STRONG>
Example taxonomic notations.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/SSDtaxonomic.eps}$ -->
<IMG
 WIDTH="666" HEIGHT="219" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg100.gif"
 ALT="\includegraphics{p/SSDtaxonomic.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>

<H2><A NAME="SECTION00645000000000000000">
4.4.5 Constraint Checking</A>
</H2>

<P>
TSSD checks also the soft and immediately enforced constraints that are
summarized in figure&nbsp;<A HREF="usersguidenode6.html#SSDConstraints">4.23</A>.

<P>
<BR>
<DIV ALIGN="CENTER"><A NAME="SSDConstraints">&#160;</A><A NAME="4771">&#160;</A>
<TABLE WIDTH="50%">
<CAPTION><STRONG>Figure 4.23:</STRONG>
Immediately checked and soft constraints on SSDs.</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">

<!-- MATH: $\includegraphics{p/SSDconstraints.eps}$ -->
<IMG
 WIDTH="537" HEIGHT="528" ALIGN="BOTTOM" BORDER="0"
 SRC="usersguideimg101.gif"
 ALT="\includegraphics{p/SSDconstraints.eps}"></DIV></TD></TR>
</TABLE>
</DIV>
<BR>
<P>
<BR><HR><H4>Footnotes</H4>
<DL>
<DT><A NAME="foot4200">...
line&nbsp;</A><A NAME="foot4200"
 HREF="usersguidenode6.html#tex2html67"><SUP>4.1</SUP></A>
<DD>Or more pedantic: what is the first 
and what is the last segment of a line is actually determined by the 
direction in which the edge was originally drawn. For undirected edges like a 
binary relationship this direction is irrelevant, as both sides have 
possibly a cardinality constraint and a role name. For directed edges 
like functions, this direction is visible by the shape of the line.

<DT><A NAME="foot4778">... <B>operations</B>&nbsp;</A><A NAME="foot4778"
 HREF="usersguidenode6.html#tex2html79"><SUP>4.2</SUP></A>
<DD>In the past, an operation in TCRD 
was also called <B>event</B>, <B>transition</B> or <B>action</B>.

</DL><HR>
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<ADDRESS>
<I>Henk van de Zandschulp</I>
<BR><I>2003-01-20</I>
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