What is the main of the image post before?!
The reason, the advantage to use a logical name?!
Call it "alias" of a phisical name IMHO is reductive, i image that there is more about it.
It's correct? Is only a problem of portability of code.r from a system to other?
]]>Logical Database Name
The logical database name is used to resolve ambiguous database references.
That is, when a procedure is compiled against a database, it is the logical database name that is stored in the procedure's object code (]]>file_oe.r?), and when a procedure executes, its database name references must match the logical name of a connected database.
Il nome logico del DB è usato per risolvere i riferimenti ambigui alle base di dati.
Cioè quando una procedura è compilata “contro?” “relativamente a?” “in?” una base di dati, è il nome logico del DB a venire immagazzinato nel codice oggetto della procedura (file_oe.r ?), e quando una procedura è eseguita, i suoi riferimenti al nome del DB devono uguagliare il nome logico del DB collegato.
Yes, it is a mechanism so that the same r-code can be used against multiple databases. Think of it as a virtual database slot into which you can plug any number of alternate physical databases.
Of course, it can also be used to keep things straight if you connect multiple databases at the same time.
Consulting in Model-Based Development, Transformation, and Object-Oriented Best Practice http://www.cintegrity.com
]]>Of course, it can also be used to keep things straight if you connect multiple databases at the same time.
Ehhhh this i don't understand, (i've a hard little head ), how can do this?
You said what is draw in the picture correct?
If it is, i don't understand what the picture rapresent ...
I mean simply that, if one has two or more databases connected at the same time, the alias or logical name allows one to be clear about which table in which database is meant by any given reference. E.g., In Tom Bascom's technique of replication he is connecting processes to both the source and target databases and copying from one to the other. Both databases have exactly the same schema, so the logical name is needed to identify that one is reading from the source and writing to the target.
Ah ok, ma the virtualization is a conseguence of the portablity definition.
That is, when a procedure is compiled against a database, it is the logical database name that is stored in the procedure's object code, and when a procedure executes, its database name references must match the logical name of a connected database.
Alias for me is reductive, logical or virtual dbname IMHO is better.
Is also the case of a DB multivolume:
Multiple databases, yes. Multiple extents, no, since they are part of the same logical database.