Oracle, MySQL, Cassandra, Hadoop Database Training Classes in Leipzig, Germany

Learn Oracle, MySQL, Cassandra, Hadoop Database in Leipzig, Germany and surrounding areas via our hands-on, expert led courses. All of our classes either are offered on an onsite, online or public instructor led basis. Here is a list of our current Oracle, MySQL, Cassandra, Hadoop Database related training offerings in Leipzig, Germany: Oracle, MySQL, Cassandra, Hadoop Database Training

We offer private customized training for groups of 3 or more attendees.

Oracle, MySQL, Cassandra, Hadoop Database Training Catalog

cost: $ 495length: 1 day(s)
cost: $ 1190length: 3 day(s)
cost: $ 1090length: 3 day(s)
cost: $ 1190length: 3 day(s)
cost: $ 1090length: 2 day(s)

Cassandra Classes

Hadoop Classes

cost: $ 1590length: 3 day(s)

Linux Unix Classes

cost: $ 1890length: 3 day(s)

Microsoft Development Classes

MySQL Classes

cost: $ 490length: 1 day(s)
cost: $ 790length: 2 day(s)
cost: $ 1290length: 4 day(s)
cost: $ 1190length: 3 day(s)

Oracle Classes

cost: $ 2090length: 5 day(s)
cost: $ 1190length: 3 day(s)
cost: $ 2090length: 5 day(s)
cost: $ 2090length: 5 day(s)
cost: $ 2090length: 5 day(s)
cost: $ 2090length: 5 day(s)
cost: $ 1190length: 3 day(s)
cost: $ 2090length: 5 day(s)
cost: $ 1590length: 4 day(s)
cost: $ 790length: 2 day(s)
cost: $ 690length: 1 day(s)
cost: $ 2800length: 5 day(s)
cost: $ 1690length: 3 day(s)
cost: $ 2600length: 5 day(s)

SQL Server Classes

cost: $ 1290length: 3 day(s)
cost: $ 890length: 2 day(s)
cost: $ 2090length: 5 day(s)
cost: $ 2090length: 4 day(s)
cost: $ 2090length: 5 day(s)
cost: $ 2190length: 5 day(s)
cost: $ 1290length: 3 day(s)

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Gain insight and ideas from students with different perspectives and experiences.

Blog Entries publications that: entertain, make you think, offer insight

The original article was posted by Michael Veksler on Quora

A very well known fact is that code is written once, but it is read many times. This means that a good developer, in any language, writes understandable code. Writing understandable code is not always easy, and takes practice. The difficult part, is that you read what you have just written and it makes perfect sense to you, but a year later you curse the idiot who wrote that code, without realizing it was you.

The best way to learn how to write readable code, is to collaborate with others. Other people will spot badly written code, faster than the author. There are plenty of open source projects, which you can start working on and learn from more experienced programmers.

Readability is a tricky thing, and involves several aspects:

  1. Never surprise the reader of your code, even if it will be you a year from now. For example, don’t call a function max() when sometimes it returns the minimum().
  2. Be consistent, and use the same conventions throughout your code. Not only the same naming conventions, and the same indentation, but also the same semantics. If, for example, most of your functions return a negative value for failure and a positive for success, then avoid writing functions that return false on failure.
  3. Write short functions, so that they fit your screen. I hate strict rules, since there are always exceptions, but from my experience you can almost always write functions short enough to fit your screen. Throughout my carrier I had only a few cases when writing short function was either impossible, or resulted in much worse code.
  4. Use descriptive names, unless this is one of those standard names, such as i or it in a loop. Don’t make the name too long, on one hand, but don’t make it cryptic on the other.
  5. Define function names by what they do, not by what they are used for or how they are implemented. If you name functions by what they do, then code will be much more readable, and much more reusable.
  6. Avoid global state as much as you can. Global variables, and sometimes attributes in an object, are difficult to reason about. It is difficult to understand why such global state changes, when it does, and requires a lot of debugging.
  7. As Donald Knuth wrote in one of his papers: “Early optimization is the root of all evil”. Meaning, write for readability first, optimize later.
  8. The opposite of the previous rule: if you have an alternative which has similar readability, but lower complexity, use it. Also, if you have a polynomial alternative to your exponential algorithm (when N > 10), you should use that.

Use standard library whenever it makes your code shorter; don’t implement everything yourself. External libraries are more problematic, and are both good and bad. With external libraries, such as boost, you can save a lot of work. You should really learn boost, with the added benefit that the c++ standard gets more and more form boost. The negative with boost is that it changes over time, and code that works today may break tomorrow. Also, if you try to combine a third-party library, which uses a specific version of boost, it may break with your current version of boost. This does not happen often, but it may.

Don’t blindly use C++ standard library without understanding what it does - learn it. You look at std::vector::push_back() documentation at it tells you that its complexity is O(1), amortized. What does that mean? How does it work? What are benefits and what are the costs? Same with std::map, and with std::unordered_map. Knowing the difference between these two maps, you’d know when to use each one of them.

Never call new or delete directly, use std::make_unique and [cost c++]std::make_shared[/code] instead. Try to implement usique_ptr, shared_ptr, weak_ptr yourself, in order to understand what they actually do. People do dumb things with these types, since they don’t understand what these pointers are.

Every time you look at a new class or function, in boost or in std, ask yourself “why is it done this way and not another?”. It will help you understand trade-offs in software development, and will help you use the right tool for your job. Don’t be afraid to peek into the source of boost and the std, and try to understand how it works. It will not be easy, at first, but you will learn a lot.

Know what complexity is, and how to calculate it. Avoid exponential and cubic complexity, unless you know your N is very low, and will always stay low.

Learn data-structures and algorithms, and know them. Many people think that it is simply a wasted time, since all data-structures are implemented in standard libraries, but this is not as simple as that. By understanding data-structures, you’d find it easier to pick the right library. Also, believe it or now, after 25 years since I learned data-structures, I still use this knowledge. Half a year ago I had to implemented a hash table, since I needed fast serialization capability which the available libraries did not provide. Now I am writing some sort of interval-btree, since using std::map, for the same purpose, turned up to be very very slow, and the performance bottleneck of my code.

Notice that you can’t just find interval-btree on Wikipedia, or stack-overflow. The closest thing you can find is Interval tree, but it has some performance drawbacks. So how can you implement an interval-btree, unless you know what a btree is and what an interval-tree is? I strongly suggest, again, that you learn and remember data-structures.

These are the most important things, which will make you a better programmer. The other things will follow.

I will begin our blog on Java Tutorial with an incredibly important aspect of java development:  memory management.  The importance of this topic should not be minimized as an application's performance and footprint size are at stake.

From the outset, the Java Virtual Machine (JVM) manages memory via a mechanism known as Garbage Collection (GC).  The Garbage collector

  • Manages the heap memory.   All obects are stored on the heap; therefore, all objects are managed.  The keyword, new, allocates the requisite memory to instantiate an object and places the newly allocated memory on the heap.  This object is marked as live until it is no longer being reference.
  • Deallocates or reclaims those objects that are no longer being referened. 
  • Traditionally, employs a Mark and Sweep algorithm.  In the mark phase, the collector identifies which objects are still alive.  The sweep phase identifies objects that are no longer alive.
  • Deallocates the memory of objects that are not marked as live.
  • Is automatically run by the JVM and not explicitely called by the Java developer.  Unlike languages such as C++, the Java developer has no explict control over memory management.
  • Does not manage the stack.  Local primitive types and local object references are not managed by the GC.

So if the Java developer has no control over memory management, why even worry about the GC?  It turns out that memory management is an integral part of an application's performance, all things being equal.  The more memory that is required for the application to run, the greater the likelihood that computational efficiency suffers. To that end, the developer has to take into account the amount of memory being allocated when writing code.  This translates into the amount of heap memory being consumed.

Memory is split into two types:  stack and heap.  Stack memory is memory set aside for a thread of execution e.g. a function.  When a function is called, a block of memory is reserved for those variables local to the function, provided that they are either a type of Java primitive or an object reference.  Upon runtime completion of the function call, the reserved memory block is now available for the next thread of execution.  Heap memory, on the otherhand, is dynamically allocated.  That is, there is no set pattern for allocating or deallocating this memory.  Therefore, keeping track or managing this type of memory is a complicated process. In Java, such memory is allocated when instantiating an object:

String s = new String();  // new operator being employed
String m = "A String";    /* object instantiated by the JVM and then being set to a value.  The JVM
calls the new operator */

Let's face it, IT roles have evolved and are no longer meant for the IT department alone. Most departments tend to have a technical person that can help make sense of data. These days, businesses encourage data democratization, meaning that everyone in the business is responsible for the information that the organization receives. Departments no longer have to wait for data to pass through IT before they receive it. The departments get information as it comes. Then, they make decisions based on that data. 

IT Job Roles and Responsibilities

1. Project Manager

A project manager, in this case, is someone that plays a managerial role in a company’s project. In fact, this is one of the most important IT job roles. The manager is responsible for his or her team. He or she makes sure that deadlines are met, and the project proceeds as planned. It mainly includes planning, design, initiation, monitoring, execution, and control. 


2. IT Director

In most cases, the term director is associated with big positions in a company, and is often associated with a board role. As one of the top IT job roles, the IT director is responsible for planning, managing and executing the core-infrastructure of a company. The primary role of the IT director is to oversee all the technology operations within the firm. The director then evaluates what his or her team does to make sure that the activities are in line with firm’s main objectives. On top of that, the IT director makes sure that all departments have their technology needs met by his or her team. 

3. IT Manager

The rank of an IT manager is definitely lower than that of a director, however, the role is still very crucial for any IT department. Every IT department has staff members that are meant to deliver results at the end of the day. The IT manager supervises most of the workers in the IT department. He or she is in charge of motivating them and making sure that they do what they are supposed to do. The IT manager’s roles include monitoring, planning, coaching, disciplining employees, and counseling.

4. Software Engineer

This position can also be referred to as a software architect, system engineer or application programmer. The main work typically involves creating and programming system-level software such as database systems, operating systems, and embedded systems. Their primary role is to ensure that they understand how both software and hardware work and to use them appropriately. However, the responsibilities don’t stop there. The software engineer is also required to interact with both colleagues and clients to explain which system or solution is going to be more suitable for use. 

5. Systems Analyst

A systems analyst can also be called a solutions specialist, product specialist or a systems engineer. Their primary work mainly involves identifying, analyzing, and coming up with new information systems that will provide a viable solution. This is mostly done as a response to the requests of customers or just for the business. They also have to make sure that they determine the costs and total time required to bring the information systems into effect. 

6. Helpdesk Support

There are times when your team could encounter system problems. Perhaps, a piece of hardware or software has malfunctioned. You need helpdesk support to deal with such issues. This is a professional that knows about common computer problems. Without them, business operations could stall because an employee can be stranded, and there’s no one to help. 

7. Network Designer

As much as helpdesk support can solve most IT problems, there are other issues that they can’t solve. You may experience system shutdowns or slow internet. In that case, you need an expert in maintaining communication systems. These professionals will also be responsible for setting up cyber security systems for the organization. 


IT involves many job roles and responsibilities that all work hand-in-hand to deliver results. As you begin your business, you should know about these roles so that you can know which ones are going to be the most suitable for your firm. 

We are not all equally motivated. Some people have more self-drive than other people. This is why we find that some people always end up at the top even when the odds are against them. An employee, with this realization, through the Human Resource department, should be able to design efficient career development systems. For this system to work, the employer must understand the nature of the business environment in which they are operating.

Why Train Employees?

The purpose of training employees is to enable them to grow with time and increase their efficiency. The business world is quite dynamic, nothing stays the same for long. Training one’s employees allows them to keep abreast with the ever changing technological advancements and many other factors that are relevant to his/her line of work. Employees cannot be expected to solve all their employer’s expectations with static skills and techniques. Even the most updated technology becomes obsolete at some point.
People are the biggest assets in organizations. For an establishment to flourish, it is important that the employer understands certain key things that help spur their development.

In a report from the Harvard Business Review, “The Impact of Employee Engagement of Performance,” the most impactful employee drivers are:

training details locations, tags and why hsg

A successful career as a software developer or other IT professional requires a solid understanding of software development processes, design patterns, enterprise application architectures, web services, security, networking and much more. The progression from novice to expert can be a daunting endeavor; this is especially true when traversing the learning curve without expert guidance. A common experience is that too much time and money is wasted on a career plan or application due to misinformation.

The Hartmann Software Group understands these issues and addresses them and others during any training engagement. Although no IT educational institution can guarantee career or application development success, HSG can get you closer to your goals at a far faster rate than self paced learning and, arguably, than the competition. Here are the reasons why we are so successful at teaching:

  • Learn from the experts.
    1. We have provided software development and other IT related training to many major corporations in Germany since 2002.
    2. Our educators have years of consulting and training experience; moreover, we require each trainer to have cross-discipline expertise i.e. be Java and .NET experts so that you get a broad understanding of how industry wide experts work and think.
  • Discover tips and tricks about Oracle, MySQL, Cassandra, Hadoop Database programming
  • Get your questions answered by easy to follow, organized Oracle, MySQL, Cassandra, Hadoop Database experts
  • Get up to speed with vital Oracle, MySQL, Cassandra, Hadoop Database programming tools
  • Save on travel expenses by learning right from your desk or home office. Enroll in an online instructor led class. Nearly all of our classes are offered in this way.
  • Prepare to hit the ground running for a new job or a new position
  • See the big picture and have the instructor fill in the gaps
  • We teach with sophisticated learning tools and provide excellent supporting course material
  • Books and course material are provided in advance
  • Get a book of your choice from the HSG Store as a gift from us when you register for a class
  • Gain a lot of practical skills in a short amount of time
  • We teach what we know…software
  • We care…
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