System and Global Projects

This chapter describes how AVEVA Administration elements and their attributes, in a System Database (DB), differ when a Global Project is used.

The administrator can navigate to the elements in the System and Global DBs, and query their members and attributes in the normal way.

A full list of elements and their attributes is included in Data Model.

Session information is stored separately in the Comms DB; and the Misc DB stores inter-DB macros and messages. The communications World element in the Comms DB contains the Project lock. This may be set or cleared using LOCK and UNLOCK syntax.

When the administrator uses the MAKE GLOBAL command to make a Standard Project into a Global Project, the Standard System DB is split into two new DB files; the Global DB and the (local) System DB.

A modified sysvir.dat virgin DB is used to upgrade the System DB file xxxsys, where 'xxx' is the 3-character Project code. The Comms World element LCOMW is added. The glbvir.dat DB template file is used to create the Global DB file xxxglb.

The existence of the xxxglb DB file shows that the Project is Global.

The following elements are added:

• The Comms World element LCOMW.

• The Global Locations World element GLOCW, which will own GRPLI elements which in turn own GRP elements.

• The Global Team World element GTMWL.

• The Global Stamp World element GSTWLD. If stamps exist in the System DB, they are all copied to the Global Stamp World element and deleted from the System DB.

The attributes of these elements and their members, and the changes to other AVEVA Administration DB elements which occur when a Project is made Global, are described in the following pages.

The Global DB contains information that is common to all Locations running a Global Project. The Global DB is readable at all Locations but it can only be written to at the Hub. Changes to the Global DB are propagated to all the other Locations. This means that the Global DB is the same at every Location, except during the short time changes are being propagated.

Each local System DB contains Project information that is specific to the Location. The local administrator can write to the local System DB. A local System DB is similar to the System DB in a non-Global Project. The main difference is that some of the Standard AVEVA Administration elements will be redundant. The differences are described below.

Session information is stored separately in the Comms DB; and the Misc DB stores inter-DB macros and messages. The Comms and Misc DBs are local to each Location.

The Comms World element in the Comms DB contains the Project lock and isolation flags. The Project lock may be set or cleared using LOCK and UNLOCK; and the Isolation flag may be set true or false using the ISOLATION syntax. Both LOCK and Isolation may be set or queried remotely by the Hub or an administering Location.