Databases Reference
In-Depth Information
resources you use, so this elasticity is reflected in more efficient use of resources
and the resulting lower cost. For databases, the focus of this topic, elasticity mainly
has to do with easy scaling up, since the amount of data typically only increases
over time. However, even a database may use differing amounts of CPU and mem‐
ory resources, so some cloud solutions offer differential rates based on fluctuations
in these demands.
These four characteristics are common across virtually all cloud solutions. But all cloud
solutions are not the same, as the following section details.
Cloud Levels
There are different levels of cloud products based on levels in the standard IT stack.
These levels are, in ascending order in the stack:
Infrastructure-as-a-Service (IaaS)
Provides hardware and system-level software at a basic level. The leading IaaS
product is Amazon's Elastic Compute Cloud (EC2).
Database-as-a-Service (DBaaS)
Provides a dedicated database in the cloud. The Oracle Database is available as a
DBaaS from Amazon as one of the Relational Data Services (RDS) and from Oracle's
Cloud Managed Services, among other vendors at the time of this writing.
Platform-as-a-Service (PaaS)
Provides a deployment and, optionally, a development environment in the cloud.
The Oracle Database Cloud Service provides an Oracle database as a PaaS product,
and the Oracle Java Cloud Service provides a Java deployment platform. The
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Software-as-a-Service (SaaS)
Provides a complete application system in the cloud. Oracle has a wide range of
SaaS offerings, as do many other vendors.
All of these levels share two common, and crucially defining, characteristics:
The service level of an offering determines the interface to the service
Each level utilizes the interface normally used by the software service level. For
example, you would connect to an Oracle Database instance using SQL*Net. You
would interact with the functionality of the Oracle Database from a development
environment using SQL or PL/SQL. In a similar way, you use SQL*Net to access an
Oracle database in a DBaaS offering. You would use SQL and PL/SQL to access an
Oracle database used in a PaaS offering.
The service level of an offering determines the access you get to the component software
In a nutshell, everything below the service level is hidden in the cloud. The downside
of this characteristic is that you cannot, for instance, modify the configuration of
