Operational Differences - InterSystems Documentation

1MV Accounts and CachéNamespacesBoth MV and Caché have the concept of a logical space to hold groups of related programs and data.In MV, this space is called an ACCOUNT; Caché calls it a NAMESPACE. Because of this similarity,it is natural to consider mapping MV accounts to Caché namespaces since this will also provide theeasiest access to all the other facilities that Caché provides for MV applications.Similarity is not identity, however. The rules for forming MV account names differ from those forCaché namespaces. The following describes the differences between them and how those differenceare resolved.• An MV account name could contain any character from the extended ASCII character set.• Caché namespace names are at least one character long, starting with an alphabetic character ora percent sign, and followed by an arbitrary number of alphanumerics, dashes or underscores.• In the simplest case, a Caché namespace maps to a Caché database of the same name. Cachédatabase names are between 1 and 30 characters long, can start with an alphabetic character or anunderscore. The remaining characters can be alphanumeric, dash, or underscore.1.1 Converting the Account NameIn transforming the account name for Caché, it is desirable to end up with a result that doesn't altersimple names, that transforms non-conforming account names in an obvious way, and that results ina string acceptable for both the namespace and the database name. To that end, the following algorithmis used to transform an MV account name into the required Caché namespace and database names.Operational Differences between MultiValue and Caché 3