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Junior Database Developer seeking support


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I have recently started a new position in my company as a Junior Database Developer. I have previously worked in Data Analysts roles; mainly using advanced Excel & VB.

I have a strong passion for SQL, as I now aim to develop my career down the Database Developer route.

 

In my first month, I have began to get to grips with using SQL syntax; building and creating tables etc. Whilst I appreciate it takes time to understand how processes work, I am eager to further understand what things mean; how things work & why.

 

After reading up on numerous forums, not everything is explained easily for beginners. I much prefer seeing working examples of things, using analogies.

 

I am reaching out to SQL gurus to help explain a few items for me. Unfortunately, I am unable to attach the Word document with my requirements.

 

If anybody can be of any support, and therefore get in touch, I will be very grateful!

 

Regards,

 

Ben

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As we sometimes say, what's your first question?

Edited by niche
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I think the important thing about databases isn't to memorize SQL, but learning how to structure data. There are entire courses devoted to database engineering, so I don't think a forum thread is enough to teach you everything.

 

SQL works with relational databases, which are the most common kind. In a relational database each database has a table, each table has rows and each row has fields. Each table specifies a type of data, each row in the table refers to one object and the fields represent properties of that object.

 

Sometimes objects are related, for example a Person has a Job.

 

A Person table would have fields like "name", "age" and "gender" while the Job table would have "job_name", "job_description" and "salary". You would need to create a relation between the Person and Job tables. SQL does it with FOREIGN KEY. The foreign key can only associate one person with one job. If you want multiple people for a job, or multiple jobs for a person, you need an intermediate table where each row has a field for Person and another for Job. You also need to make sure that those rows are unique, you could use PRIMARY KEY(person,job) to ensure that each person-job combination can only occur once.

 

The W3Schools SQL tutorial is an OK place to start, but if you really want to be valuable to your employer you might want to take a course in database theory.

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Hi,

 

Thanks for the quick reply.

 

For starters I'm interested in understanding how databases work? How do they retrieve data from systems used in companies?

 

Also....

 

- How does SQL Server Management Studio work with Visual Studio?

 

- How does a server work and what is its main purpose?

 

- Why may a company use numerous servers, databases and tables to hold company data?

 

- Stored Procedures - I know a little bit, but how do they actually work and when & how do we use them?

 

Regards

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Thanks Ingolme,

 

I am attending a course next month; 'Querying SQL Server'.

 

As I am currently working on a test server environment, there is a lot of opportunity to 'play' around with data in SQL Server, however there are a lot of databases and tables, which is already giving me a headache. (A good one of course!).

 

I am always wanting to know why & how things work.

 

SQL is a fantastic career path for any data savvy individual!

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For practicing, I would like to suggest W3Schools SQL tutorial. They have a good interface to test queries you've learnt: http://www.w3schools.com/sql/trysql.asp?filename=trysql_select_all

 

If you have full access to an SQL server just for practicing (where mistakes wouldn't be a danger) just practice with one database and a couple of tables. Make the tables yourself so that you know what their structure is and what's in them.

 

If there's something specific in the SQL tutorial that you don't understand then ask about it here.

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In my first month, I have began to get to grips with using SQL syntax; building and creating tables etc. Whilst I appreciate it takes time to understand how processes work, I am eager to further understand what things mean; how things work & why.

 

So far I've taken four courses in database and I'm still just a beginner -- so I wonder how they could put you in such a position if you have no exposure to databases? I would suggest you obtain a few database theory textbooks and then some reference books on the particular flavor of database(s) that your company uses.

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I have been working with SQL tutorials for the past 6 months, whilst also having some knowledge of RDBMS for a while.

 

Learning the syntax isn't too much of a challenge if you know the data.

 

In my case, I'm more wanting to understanding the components of how things work. I'm getting exposed to things daily, which I'm learning continuously.

 

Using analogy examples, this helps me to logically understand HOW things work.

 

Hearing how things work from people really helps with my learning styles, hence why I joined here. Textbooks don't always do it for me as they don't answer questions. However, if you know of any decent sources, please post them.

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Those are some fairly basic questions. That doesn't mean they're easy though. You might want to go to a site like oreilly.com and check their list of database books, that would probably be a good start.

For starters I'm interested in understanding how databases work? How do they retrieve data from systems used in companies?

The specifics of how databases store and retrieve data aren't part of any standard. SQL Server will store and retrieve data a different way than MySQL would, for example. Even within MySQL, you can choose various storage engines (MyISAM, InnoDB, etc) which each store and retrieve data differently. Each storage engine is optimized for specific use cases (MyISAM, for example, is optimized for a very large number of select queries versus a relatively small number of inserts, updates, and deletes).

How does SQL Server Management Studio work with Visual Studio?

I believe they are separate, or at least I've never integrated them (I don't work with VS much). I've used the SQL Server tools to do all of the database administration work directly, I haven't actually integrated that with VS in any way.

How does a server work and what is its main purpose?

A server is any piece of software which can listen for and respond to requests from a client. There are web servers, mail servers, file servers, database servers, etc.

Why may a company use numerous servers, databases and tables to hold company data?

That's kind of vague. We have several web servers, each with a database server, because some clients pay for dedicated servers, others use shared servers. We have multiple shared servers because any one server can only handle so much traffic. Each application will typically use its own database.

Stored Procedures - I know a little bit, but how do they actually work and when & how do we use them?

Again, how stored procedures are implemented are left up to the database vendors. You would use one when you want to encapsulate your business logic on the server instead of in a query. Some companies have developers which only write the stored procedures, and other developers use them in the applications. The developers using the stored procedures don't need to understand the underlying database structure, they can just call the SPs. It's typically faster to use an SP than a query that does the same thing.
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Obviously as a first step you need to completely understand normalization and foreign keys...

 

http://en.wikipedia.org/wiki/Database_normalization

 

http://en.wikipedia.org/wiki/Foreign_key

 

Another critical database topic is security and access control...

 

http://en.wikipedia.org/wiki/Database_security

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