The JDO database of the company Versant (formerly Poet) is called FastObjects. We use the T7 version.
The database connection is opened via a connectionURL. It has the following syntax: fastobjects://<host>/<name> (e.g. fastobjects://localhost/TestDB)
For an EEC installation, the database connection is specified via the ini file:
The following is an explanation of the connection parameters host and name:
T7 can be operated in the LOCAL and Server mode:
- LOCAL mode: Both the database and client application (EEC) are located on the logical drives of a computer (for logical reasons, on a local hard disk). This mode does not require any further installations. The host to be specified in connectionURL is LOCAL.
- Server mode: A FastObjects database server must be set up on the server (see below). The host to be specified is the computer name or the IP address. If the client and server are on one computer, localhost can be used.
Each database is based on a schema. Both the schema and the database are realized as folders in the file system. If a client connects to a database, the following references must be triggered:
- The client must reference the database
- The database must reference its schema.
The reference to the schema is stored permanently within the database when a new FastObjects database is generated, and cannot be modified.
Logical names are used for both references, so that databases and schemas can be moved easily. The schema is always called SnDbDictionary.
- LOCAL mode: The logical name of the DB is entered in connectionURL. It is created as a folder in the Eclipse installation folder. The assignment to the schema and to the absolute path is done automatically by the Poet plug-in.
- Server mode: The assignment of logical names to absolute paths is realized by the configuration file ptserver.cfg (see below).
The following graphic illustrates the opening sequence of a database connection on the basis of an example:
- If FastObjectsServer.exe does not find an entry for a logical database or schema name in ptserver.cfg, the path will be assembled from the absolute path of the installation folder of the database server (in this case, c:\fastobjects\) and the logical name.
- The generation of a database follows a similar pattern. In addition to connectionURL, however, the logical name of the underlying schema is transmitted as well. The schema is always called SnDbDictionary.
- If the schema path in the ptserver.cfg file is relative, FastObjectsServer.exe will determine the absolute path from the absolute path of the database (rather than from the installation folder of the server).
During the runtime the database connection cannot be modified. To do this, it is generally necessary to shut down EEC, and then restart it with a new connectionURL (see above). It should be noted that at the start, the last visible pages will be re-generated automatically. This may require access to the database. If a DB has not been generated yet for the new connectionURL, an error message will appear at the start-up. If editors were still open at shut down, they will be opened again at the start. If the objects most recently edited are not available, this will be indicated in an error message in the editor.