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Persistent State Service |
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1. What is K2
Persistent State Service
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The K2 Persistent State Service
(PSS) is a fully compliant implementation of OMG's
specification for Persistent State Service. It
presents persistent information as storage objects
stored in storage homes. These storage homes are
in turn stored in datastores, which is an entity
that manages data, for example a database, a set
of files, a schema in a relational database.
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2. What is Berkley
DB Connector
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Berkley DB Connector provides
PSS APIs to persist data in BerkleyDB Database.
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3. What is Oracle
Connector
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Oracle Connector provides PSS
APIs to persist data in Oracle Database.
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4. How to compile
PSDL File
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K2 Persistent Service Provides
PSDL Compiler (i.e. k2cidl), to generate persistent
code from the .psdl file.
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5. While running
Client I get Error in loading configuration file
k2daemon.cfg
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K2 Persistent Service uses Logger
Service from K2 Server and it requires database_home_dir
for BerkleyDB Connector. This error can be corrected
by providing the configuration file ( from the
distribution) through command line using the option.(-K2PropFile=%K2_INSTALL_DIR%\k2\bin\k2pss.cfg)
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6. While running
Client I get Error Table or View doesn't exist
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This Error is from Oracle Connector
when there is no table exist into the Oracle DataBase
which the K2 PSS Framework tries to access. Create
the Required Tables in the Oracle DataBase and
run the Client again.
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7. Is Transaction
support available with this version
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The Current Release of K2 Persistent
State Service does not support transaction. As
a part of OTS integration with Container, the
PSS will be extended for transactional session.
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8. What is a StorageObject
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A storage object is a PSDL construct
for defining storagetype structure or schemas.
It directly represents the state stored in a database.
The programmers can define a storage object and
the state members it represent and using the K2
PSDL compiler generate the code for persistence,
for a target database. Storage object instances
are managed by the storagehome instances that
are themselves managed by the catalogs..
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9. Can I extends
K2 Persistent State Service for Custom DataBase
Persistence
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The K2 Persistent State Service
exposes number of interfaces to integrate with
third party database persistent mechanism. The
K2 Persistent State Service Framework takes care
of in memory caching and block commit features.
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10. Is it necessary
to know CORBA for using K2 Persistent State Service
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No, It is not necessary that
the programmer need to know CORBA before using
this service, but the knowledge of PSDL Language
is required. A C++ Programmer can as well write
a .psdl file using the C++ types as state members.
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11. Can I do
relational database mapping using K2 Persistent
State Service
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Yes, one can do a relational
mapping of tables using K2 Persistent State Service,
by defining a embedded StorageObject within one
another.
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