In denodo associations follow the same concept as modeling
tools, which can be described as an ‘on-demand join.’
Should Associations Be Created In the Denodo Model?
You don’t necessarily need to define an Association at every
level; usually, the best practice is to apply associations at the following
On final views published for data consumers,
indicating relationships between related views; Especially, on published web
On the component views below, any derived view
that brings together disparate (dissimilar) data sources. The associations should be defined as
Referential Constraints whenever appropriate to aid the optimization engine.
On the component views below, any derived view
that joins a “Base View from Query” with standard views, since Base
Views from Query cannot be rewritten by the denodo optimization engine. Often Base Views from Query create
These best practices should cover the majority scenarios;
beyond these guidelines, it is best to take an ad-hoc approach to create
Associations when you see a specific performance/optimization.
Are Associations important in Denodo?
In a nutshell, associations performance and the efficiency
of the denodo execution optimizer along with other model metadata, such as:
A coworker recently asked a question as to whether denodo
generated joins automatically from source RDBMS database schema. After searching, a few snippets of
information became obvious. First, that
the subject of inheriting join properties was broader than joins and needed to
in modeling associations (joins on demand). Second, that there were some denodo
design best practices to be considered to optimize associations.
Denodo Automatically Generate Joins From the Source System?
After some research, the short answer is no.
Denodo Inherit Accusations From A Logical Model?
The short answer is yes.
Denodo bridges allow models to be passed to and from other
modeling tools, it is possible to have the association build automatically,
using the top-down approach design approach and importing a model, at the
Interface View level, which is the topmost level of the top-down design
However, below the Interface view level, associations and or joins are created manually by the developer.
While researching an old install for an upgrade system
requirement compliance, I discovered that I b=need to validate which Linux
version was installed. So, here is a
quick note on the command I used to validate which version of Linux was
denodo 7.0 saves some manual coding when building the ‘Base Views’ by performing some initial data type conversions from ANSI SQL type to denodo Virtual DataPort data types. So, where is a quick reference mapping to show to what the denodo Virtual DataPort Data Type mappings are:
ANSI SQL types To Virtual DataPort Data types Mapping
ANSI SQL Type
Virtual DataPort Type
BIT VARYING (n)
CHARACTER VARYING (n)
DECIMAL (n, m)
NUMERIC (n, m)
TIMESTAMP WITH TIME ZONE
VARCHAR ( MAX )
ANSI SQL Type Conversion Notes
The function CAST truncates the output when converting a value to a text, when these two conditions are met:
You specify a SQL type with a length for the target data type. E.g. VARCHAR(20).
And, this length is lower than the length of the input value.
When casting a boolean to an integer, true is mapped to 1 and false to 0.
The new CentOS 8 rebuild
is out. Christened version 8.0-1905, this release provides a secure, stable and
a more reliable foundation for CentOS users such as organizations running
high-performance websites and businesses with Linus experts that use CentOS
daily for their workloads, but who do not need strong commercial support.
The new OS comes in
after Red Hat released RHEL 8 – Red Hat Enterprise Linux – in May of this year.
According to CentOS 8 release notes, the contributors note that this rebuild is
100% compliant with Red Hat’s redistribution policy. This Linux distro allows
users to achieve successful operations using the robust power of an
enterprise-class OS, but without the cost of support and certification. Below
are some of the updates as outlined in CentOS 8 release notes that you can
expect with this new release and some of the deprecated features.
What’s New in the Just Released CentOS 8?
BaseOS and Appstream
New container tools
TCP stack improvements
· BaseOS and Appstream
The main repository or
Base Operating System offers the components of distribution that in turn
provide the running user space on the hardware, virtual machines, or even a
container. The Application Stream or App stream offers all the apps you might
want to run in particular user space. The Supplemental repository offers
software that comes with special licensing.
· New Container Tools
With the aid of Podman,
CentOS 8 supports Linux Containers. This replaces Docker and Mobdy, which
depend on daemon and run as root. Unlike the previous release, the Podman in
the new version does not depend on daemon. Podman allows users to create images
from scratch using Buildah.
· Systemwide Crypto Policies
The command “update
crypto policies” can be used to update the system-wide cryptographic policy on
the new OS. The policies have settings for the following applications and
libraries; NSS TLS library, Kerberos 5 library, Open SSH SSH2 protocol
implementation, IKE protocol implementation & Libreswan IPsec, Open SSL TLS
library and GnuTLS
· TCP Stack Improvements
The CentOS 8 Linux
distro also brings with it TCP stack version 4.16 with an improved ingress
connection rate. The Linux kernel is now able to support the new BBR and NV
control algorithms. This is very helpful in helping improve the Linux server
· DNF – Dandified Yum
The new Operating System
includes the basic foundations of the Yum package but is now upgraded to the
DNF (Dandified Yum). Though it maintains a similar command-line interface and
API to its predecessor, it does promise to be faster, seamless and
The CentOS also has a
compiler based on the version 8.2 and includes support for more recent C ++
language standard versions, improved optimizations, more code, and hardening
techniques as well as new hardware support and better warnings.
In addition to those
features, the new CentOS 8 also supports secure guests, which using
cryptographically signed images will ensure that the program retains its
integrity. It also boasts of improved management of memory and support. CentOS
8 release notes state that the new OS will allow the Crash dump to take in
kernel crash during all booting phases which were not possible before.
CentOS 8 gives encrypted
storage to LUKS2. It also allows for enhancements made to the process scheduler
to include the new deadline process scheduler. This Linux distro will also
enable installations and boot from dual-in-line, non-volatile memory modules.
A great bonus feature is
that you can manage the new software with Cockpit via a web browser. This
feature is very user-friendly, making it great for system administrators and
new users alike.
If you are upgrading
from previous CentOS versions, the most significant change is seen in the
nftables framework which has replaced iptables. Nfatables allows users to
perform network address translation (NAT) mangling, packet classification, and
packet filtering. Unlike iptables, nfatables helps to provide secure firewall
support with enhanced performance, increased scalability, and easy code
These changes, though
not major, may cause problems with firewall functionality. Although upgrades
using RHEL may be supported, it is not advisable to upgrade directly from much
older versions of CentOS like CentOs 6 and below as they may not be compatible.
Users of CentOS as a
desktop will see an update of the GNOME SHELL default interface to version
3.28, while still carrying the default display server as Wayland.
If you are looking to
upgrade from previous versions, a system to do so directly is yet to be
released. As such, your most favorable option would be to back up your data as
you install the newly released CentOS 8. When it is up and running, you can
then move all the data to the new system.
Nonetheless, the new
CentOS 8 Linux release is an exciting feat. This OS provides a manageable and
consistent platform that suits a wide variety of deployments. It comes with
well-thought-out and ingenious software updates that will help avid users to
build more robust container workloads and web apps.
Well, this is one of those circumstances, where your ability
to answer this question will depend upon your user’s assigned security roles
and what you actually want.
To get a complete list, you will need to use the DBA_
administrator tables to which most of us will not have access. In the very simple examples below, you may
want to add a WHERE clause to eliminate the system schemas from the list, like
‘SYS’ and ‘SYSTEM,’ if you have access to them.
Administrator (DBA) Schema List
SELECT distinct OWNER as SCHEMA_NAME
ORDER BY OWNER;
(DBA) Schema List Results Screenshot
Fortunately for the rest of us, there are All user tables,
from which we can get a listing of the schemas to which we have access.
All Users Schema List
SELECT distinct OWNER as SCHEMA_NAME
ORDER BY OWNER;
Example All Users
Schema List Results Screenshot
Oracle help Center
> Database> Oracle > Oracle Database > Release 19
It is funny how you cannot work with some for a while
because of newer tools, and then rediscover them, so to speak. The other day I was looking at my overflow
bookshelf in the garage and saw an old book on Oracle SQL*Plus and was thinking,
“do I still want or need that book?”.
In recent years I have been using a variety of other tools
when working with oracle. So, I really hadn’t thought about the once ubiquitous
Oracle SQL*Plus command-line interface for Oracle databases, which around for
thirty-five years or more. However, I
recently needed to do an Oracle 18C database install to enable some training
and was pleasantly surprised Oracle SQL*Plus as a menu item.