What Is a Schema?
A schema is a collection of certain database objects, such as tables, indexes, and
views, all of which are owned by a user account. You can think of a “schema” as
being the same thing as a user account, but there is a slight difference—the user account houses the objects owned by a user, and the schema is that set of objects housed therein.
One definition of “schema” that you’ll often find in Oracle’s
documentation—and elsewhere—is that a schema is a “logical collection of database objects”. Technically that’s true, but it depends on how logical the user chooses to be
when building and placing those objects within his or her user account. Ideally there
should be some sense to why all those objects are in there, and ideally a “schema”
shouldn’t be just a random collection of objects, but the fact is that there is nothing
built into the Oracle or SQL systems that prevents a user from doing just that—
randomly collecting objects into a user account, and thus creating a “schema” of
Ideally, though, a user account should be seen and used as a logical
collection of database objects, driven by business rules, collected into one organized
A schema has the same name as the user account. Keep in mind, though, that
it’s entirely possible to create a schema (i.e., a user account) whose “owner” isn’t
a human being at all, but perhaps is an application process, or some other sort of
virtual entity—perhaps a particular background process—or whatever makes sense to suit the business rules that are in force. So in other words, one user will often have one user account, and therefore one schema. But the opposite isn’t necessarily true.There can be more user accounts than there are actual users.
Now that you understand what a “schema” is, and what a user account is, we can
begin to look at different types of database objects, some of which are owned by a
user—and are thereby “schema” objects—and some of which are not schema objects
but are still database objects nonetheless.
A relational database consists of collections of data known as tables. A table
could be a list of ship names and some statistics about each ship. Another table
might be a list of employees who work on different ships. The “relational”
aspect to a “relational database” has to do with the common information that
“relates” two tables together—for example, the list of employees might include
an entry for each employee’s ship assignment, which would relate back to the
list of ships and each ship’s statistics.
A relational database management system, or RDBMS, is a system in which
these relational tables and related objects can be created easily, using common
functions to add, change, and remove data and database objects from
Understand the Unique Role of SQL in Modern Software Systems
SQL is most widely used fourth-generation language (4GL) in commercial
SQL is the only language for interacting with the RDBMS. Any other
programming language must use embedded SQL calls to interact with the
The constantly changing nature of databases makes them a tricky place
to test software. If a SQL script is written and tested successfully today, it’s
entirely possible that it may break down and produce erroneous information
later on. The solution is that the script must not only be tested, but must
originally be designed and written by a capable SQL developer who understands
proper database design and is thoroughly versed in the RDBMS and
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awareness: find out the most effective ways of building awareness
communication: who we are, what we do, whom we serve, why we are worth working with
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service: FAQs, sharing good experience, smooth web page browsing, being found in search engine
I need to learn treating everything – including problems – as an Asset.
“The key is to focus on your goal and not on the plan that you initially drew up to get there.”
“With this approach, your objective doesn’t change, but you accept the fact that how you may get there might. For anyone who has put together a five year plan or even an annual budget, this is going to require thinking differently, something which is never a walk in the park. But it can be done.
To see how we need to begin by taking a step back.
However, in today’s world, it is all about exploiting the contingencies and leveraging the uncertainty by treating unexpected events as an opportunity to exercise control over the emerging situation. (Don’t believe me? Think of the last time you drew up a plan to accomplish something and it went off without a hitch.)
Those who are successful in starting companies, or creating anything new for that matter, learn not only to work with the surprise factor, but also to take advantage of it.”
“Plan B can be good, too”
“In most contingency plans, surprises are bad; the “what if?” scenarios are usually worst-case ones. But people who accept the world is much more complex today do not tie themselves to any theorized or preconceived market, strategic universe, or fixed path for making their idea a reality. For them, problems are a potential resource, as opposed to a disadvantage. They very often do something with the things that surprise them, treating those surprises as a potential asset.
How do you get creative with a surprise? Well, if the surprise is a good one, you take full advantage of it. For example, you thought the world would love your new iPhone accessory. But you have been overwhelmed by demand. The logical thing to do is to ramp up production, add distributors (perhaps worldwide), and think about creating additional products not only for the iPhone but for all other smart phones as well.
If that surprise was a negative one—i.e., your actions did not go as you thought they would; you encountered a problem or even a setback—it is then time to figure out a way of using that negative to your advantage. Problems and even setbacks are resources to be employed to your advantage.”
“Running headlong into a problem and then solving it can give you a barrier to competition, or at least a remarkable head start in the marketplace. Why? Because you acted, and the competition didn’t. As a result, you know something they don’t.
Isadore Sharp, founder of the extremely upscale Four Seasons hotel chain, serves as a case in point. When he started out, he assumed that the only thing that would matter for him was to be in the best locations. The problem he ran into was that every other hotel chain had the same idea. That was a huge negative surprise. If you are doing what everyone else is, you don’t have an advantage.
In solving that problem, he stumbled on what turned out to be the Four Seasons’ ultimate competitive advantage. He created a two-pronged barrier to entry, as he explains in his autobiography, Four Seasons: The Story of a Business Philosophy. “One was our inventory of hotels . . . the largest group of authentically first-class hotels in the world, a physical product no other company had to the same degree.”
The advantage was that he could offer the frequent traveler who wanted luxury one-stop shopping when it came to staying in any of the world’s major cities. The other advantage was his people. “Three decades ago, we had decided that what our customers most desired was whatever would make time away from home most pleasurable and productive, so we set about raising service levels to match our first-class decor, an historic judgment call that had made superior service the major determinant of hotel profitability and competitiveness, and while finally recognized now by every hotel company in the world, we had a long head start, so that all our staff in all our hotels were service-oriented, and every employee was focused on delivering service no other company could match.”
According to Sharp, “Location was no longer foremost in getting and keeping customers, it was people, people, people. This was now the decisive factor in our two-fold barrier to entry.”
That negative surprise you encounter can ultimately become a barrier to competition, if you treat it as an asset as Sharp did. He accepted the problem that what he thought was going to be an advantage—location—wasn’t. (Everyone else could build in the same place.) He then took that fact (we have terrific locations, but many other people do too) and asked what he could do with that. His conclusion: We can provide excellent service at these superior locations. That has given him a terrific edge in the marketplace.”
“Coming full circle”
“We began by talking about business clichés. Let’s end the same way. The takeaway from this post is clear. If you come across lemons—otherwise known as business problems/obstacles—do indeed make lemonade.
Try this approach next time you encounter something unexpected. Despite how unpleasant it seems, say, “This is really good news,” and then try to make it so.
The big idea here is you want to develop the ability to turn the unexpected into the profitable. That means your default position should be that there is never a problem without a potential profitable/pleasant solution lurking somewhere. The understanding that a) not all surprises are bad, and b) surprises, whether good or bad, can be used to create something new, is a central to the way we need to think going forward.
The thing is to do something positive with those surprises.”