JBG is a Java written distributed system for the navigation
in a hierarchical repository of graphs.
JBG is divided into an application Server and an applet
Client.
The JBG Server uses:
-
an external tool for the automatic layout facility. (ALF,
developed for Diagram Server)
-
a driver JDBC-ODBC to communicate with a database. (Currently
with an Access database)
-
an external database of schemas.
The JBG Client, inserted in a HTML page, connects with the
server through an Internet socket (TCP/IP Protocol), and then is ready
to start.
At the beginning the main window shows the schema of the
repository. It's a tree of schemas. The root of the tree is the most abstract
schema of the repository. The leaves, instead, are the base schemas, i.e.the
most detailed ones. A base schema is a real schema. An abstract schema,or
cluster, is a schema obtained by an operation of abstraction and/or integration
of schemas.
Every schema is an ER schema. The atomic symbol of each
ER schema are: entity, relationship and hierarchy.
In JBG each schema and each symbol are mouse-sensible.
The available operations on each abstract schema are(*):
-
Show Informations: to read the associate info about the selected
schema;
-
Open Schema: to show the correspondent ER schema;
-
Show Refined Tree: to show the refined tree, a subtree of
the repository, whose root is the selected schema.
The available operations on each base schema are(*):
-
Show Informations: to read the associate info about the selected
schema;
-
Open Schema: to show the correspondent ER schema.
The available operations on each atomic symbol are(*):
-
Show Informations: to read the associate info about the selected
symbol;
-
Open Refined Schema: to show the schema containing the objects
obtainable from the selected symbol by a refinement operation;
-
Open Abstract Schema: to show the schema containing the object
obtainable from the selected symbol by an abstraction operation;
-
Show Refined Tree: to show the refined tree, a subtree of
the repository, whose root is the schema containing the selected symbol,
and whose nodes are the schemas containing a direct or undirect refinement
of this symbol.
(*)For each object the operation can be
active or not, depending on the content of the database.
Simulation
(in italian)
Zip
file of simulation (in italian)
Help(In
italian)
HomePage
Versione
italiana