X-Git-Url: https://git.auder.net/?p=erdiag.git;a=blobdiff_plain;f=README.md;h=4cc50cf36112516395de9c947d8df44ca9afc7c9;hp=93b13149d1c9970bff222fe231a276f28126ca54;hb=HEAD;hpb=fe021b27455df1f9cd8392b2bba235029c567dec

diff --git a/README.md b/README.md
index 93b1314..4cc50cf 100644
--- 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.