Fix typo 'compact' --> 'graph' for output

[erdiag.git] / README.md

diff --git a/README.md b/README.md
index 93b1314..4cc50cf 100644 (file)
--- a/README.md
+++ b/README.md
@@ -5,27 +5,24 @@ Inspired by [this repository](https://code.google.com/archive/p/merisier/).
 This parser reads ER diagrams definition files, and produces two types of diagrams + SQL code.
 [Graphviz](https://www.graphviz.org/) is used on server side to translate parsed graph descriptions into SVG objects.
 
-*Note:* at the moment, only the conceptual graph is implemented, and no comments are allowed in textual descriptions.
-At least the former is planned, and also probably a way to indicate relative identifiers.
-
 -----
 
 An entity is defined as follow
 
-    [Entity]
-               #attr1 (*)
-               attr2 (*)
+       [Entity]
+       +attr1 (*)
+       attr2 (*)
 
-with (\*) = optional SQL indications, and # denoting a (part of) a key.
+with (\*) = optional SQL indications, and + denoting a (part of) an identifier.
 
 A relationship is defined in this way
 
-    {Relation}
-               Entity C1
-               Entity2 C2
-    --
-               attr1 (*)
-               attr2 (*)
+       {Relation}
+       Entity C1
+       Entity2 C2
+       --
+       attr1 (*)
+       attr2 (*)
 
 where attributes are optional, and C1 (resp. C2) = cardinality for entity 1 (resp. 2).
 Defining relationships with more than two attributes is easy: just add entities.
@@ -35,6 +32,14 @@ Cardinality dictionary:
  * 1 = 1..1
  * ? = 0..1
 
+Special cardinalities are also available to indicate relative identification: `?R` and `1R`.
+
+And, in case of a self-relationship, symbols '>' and '<' can indicate the sense, as in
+
+       {manage}
+       Users *>
+       Users 1<
+
 To mark a weak entity, just surround its name by extra-brackets
 
        [[WeakEntity]]
@@ -47,12 +52,23 @@ The syntax for these two last is then the same as in the non-weak versions.
 
 To indicate an inheritance relation, proceed as follow
 
-    is_a
-               Animal Cat Fish
-               Planet Mars Venus
+       is_a
+       Animal Cat Fish
+       Planet Mars Venus
 
-Finally, blocks must be separated by new lines. For a usage example, see example.html (it should render as seen in example.svg)
+Finally, blocks must be separated by new lines. For a usage example, see example.html (it should render as seen in example\_\*.svg);
+or example2.html for a bigger, more realistic illustration (small social network).
 
 Note that the "drawMcd" method can take a second argument, which indicates the type of graph.
- * "bubble" draws the standard graph, as seen [here](https://en.wikipedia.org/wiki/Entity%E2%80%93relationship_model#/media/File:ER_Diagram_MMORPG.png) for example
+ * "bubble" draws the standard graph, as seen [here](https://en.wikipedia.org/wiki/Entity%E2%80%93relationship_model#/media/File:ER_Diagram_MMORPG.png)
  * "compact" (default) use the same box for an entity and its attributes
+
+-----
+
+**TODO** list:
+
+ - functional integrity constraints (CIF)
+ - inter-relations constraints (or, and, xor, inclusion)
+ - inheritance with the right symbol (triangle)
+
+*Implementation note:* temporary dependency to [underscore](http://underscorejs.org/); used only for its shuffle() method.