Lernfeld 12 - Englisch

SQL Fundamentals
Basic features of database programs
Dynamic Host Configuration Protocol (DHCP)
DAS, NAS and SAN storage
Data Backup Methods

von Nuri Bozyigit

Task

Read the SQL Chapter in the English-Lernjob EN-RC-8.9 and answer the questions there.

Aim

1. I can explain the difference between procedural and nonprocedural languages by also explaining what SQL is.

2. I can explain what changes SQL went through in the recent years.

3. I can explain the two ways of extracting information from the data base

4. I can explain what SEQUEL means and how it is related to SQL.

5. I can name 3 functions of data handling the SQL statements perform.

6. I can explain the definition of "reserved words".

7. I can translate the bold print texts into decent german sentences.

Self-evaluation

I put a lot of effort into this work. The Lernjob was good in explaination, but i had better examples in mind, due to the fact that we already worked on this topic in the main weeks. So i basically did additional work to explain everything here more detailed.

I did research some english words, but mainly because i needed alternative ways to describe. I do know the english terms of anything i would need to build a sentence, but i am not completely familiar with alternative terms. Sometimes i don't know one or i forgot about it. In both cases, i took little time for a quick research.

1. Difference between procedural and nonprocedural languages

In order to work with procedural languages, a kind of "order" needs to be written in the corresponding programming language. This happens in form of structured programming, which requires control structures like "sequence", "selection", and "Iteration" to define the order. Nonprocedural languages such as SQL don't require structured programming, instead they make use of easier defined orders, which simply put in words what exactly it needs to do.

For example, if you need to add a person with it's informations to a list, then you do it in Java like this:

@Column: (name = "\person's name\")
private String add username here;
@Column: (name = "\password\")
private String add password here;
@Column: (name = "\email address\")
private String add emailAddress here;

This is a control structure we refer to as "sequence", where we set the order of the tasks. It is written in Java language and therefore in first glance not understandable for most of the people. You first explain that you are creating a column with "@Column" and then name it with "(name = '\add column name here\')". Then you specify the corresponding information you want to add to that column with "private String add information here". These are written one after another, just like in the example up there. That's why this control structure is called "sequence".

However, in SQL, you would write the same order like this:

INSERT INTO name_of_the_table (name, password, email address, ...)
VALUES (add the name here, add password here, add email adress here, ...);

It might not be instantly understandable for a regular person, but it's easier to understand due to it's direct expression of what it wants. In "INSERT INTO" you specify the columns you want to add the informations to. In "VALUES" you write down what information you want to add in that column. It's also worth to mention that you need to do all of these in the same order. So if you start with the column "name" then you have to write down the name first, or else you have something completely different written under the column "name". It's not too difficult to make changes in SQL, but you would rather do it right from the beginning instead of consuming up more time to fix the problem.

Additions to SQL in recent years

The majority of the programmer are all used to express their orders in a procedural manner, which was the main reason why SQL got additional functionalities containing procedural features.

Such as:

BEGIN blocks

Defines certain orders to be done once this block is approached by the programm. The procedure ends with END.

IF Statement

States an order once a certain condition is fulfilled.

YES Procedures

Defines orders once a certain condition can be answered with "yes".

Extracting information from the Database

There are 2 methods to extract informations from the database.

1st: SQL Statement

Write down an order that searches you the information you need. Let's say you're looking for senior people who are older than 40 and whom's salaries are more than 60.000. Your order would look like this:

SELECT * FROM EMPLOYEE
WHERE Age > 40 OR Salary > 60000

2nd: Query

Query is a question you ask the database. If the condition fits any data in the database, these data's are then displayed.

What is SEQUEL and what does it have to do with SQL

In the early 1970's, the company IBM developed a DBMS system (known as RDBMS), which also got it's own sublanguage to work with called SEQUEL (Structured English QUEry Language). However, to their bad luck, a company had already a trademark on the name "SEQUEL", which resulted to the decision to rename this language to something different, but yet at the same time, recognizable as a member of the same family: SQL.

SQL is based on structured english, such as it's original name was. But it does not stand for "Structured English query Language" like many people would assume. It's rather a sequence of 3 letters without any meaning behind them. Such as the computer language C, which has a meaning as a word, but not as a single letter.

How SQL handles data's

There are 3 methods to how SQL handles the data's in the database.

1st: Defining Data

Defining Data basically means to add informations to the database. Just like our recently mentioned order, INSERT INTO:

INSERT INTO name_of_the_table (name, password, email address, ...)
VALUES (add the name here, add password here, add email adress here, ...);

2nd: Manipulate Data

Manipulating Data basically means to change informations on the Database. Good examples would be to delete or update specific datas. The best sample would be to show how to update those:

UPDATE name_of_the_table
SET first column name = add new value here, second column name = add new value here, [...]
WHERE write down here where to change;

3rd: Control Data

Controlling Data means to look up and filter information you need with various methods. The best way to demonstrate that is with a "SELECT" oder paired with a "WHERE" order.

SELECT name of the column
FROM name_of_the_table
WHERE The column where the information is = 'what you're looking for';

What is "reversed words"

To be completely honest, i don't know either. I tried to understand what the Lernjob explained and i also tried to research the meaning, but none of the informations i came across with where understandable for me.

I also tried to ask classmates but they are lost cases here too.

Translate the text in bold print

Original

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Translation

Der Satzbau von SQL ist in strukturiertem Englisch, von dem auch der ursprüngliche Name stammt. Jedoch ist SQL keine strukturierte Sprache so wie die meisten Informatiker vermuten würden. Daher bedeutet SQL nicht wie alle denken "Structured query Language". Es ist eher eine Reihe von Buchstaben die nicht für bestimmte Worte stehen, vergleichbar mit dem Namen "C", welches als einzelner Buchstabe ebenfalls keine Bedeutung trägt.

Die Arbeit der Firma von IBM, welches sich mit Datenbanken und SQL befasste, war bereits sehr bekannt in der Industrie, selbst bevor der SQL/DS Datenbank (RDBMS) in 1981 veröffentlicht wurde. Zu der Zeit hat Relational Software Inc. (heute bekannt als Oracle Corporation) seine erste RDBMS bereits veröffentlicht. Diese frühen Produkte haben sehr schnell einen Standard für Database Management Systems deklariert. Es beinhaltete die SQL Sprache, welches fortan als gängiger Standard der Verwaltungssprache verwendet wurde. Verkäufer anderer RDBMS machten ebenfalls Gebrauch von SQL, welches aber immer wieder neu interpretiert wurde. Als Resultat gab es eine große Auswahl an Datenbanken mit individuellen SQL Sprachen, aber die Kompatibilität miteinander ließ sehr zu wünschen übrig.