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I've never had much need for programming with databases. Since their use is so widespread it seems like a good thing for me to learn. SQL seems like the place to start, possibly SQLite and maybe the Python bindings. What would you recommend for someone new to this? Libraries, tools and project ideas are all welcome.
Structure Query Language (SQL) is the language used to talk to database management systems (DBMS). While it's a good thing to learn, it's probably best to do it with a project in mind that you'd like to do. It's funny you say you've never had a need, because I'm the opposite, almost every program I've ever written has used a database of some sort. The vast majority (mostly web-based) revolve around using a database.
Learn about relations and database architecture. This means how to structure your tables, make foreign keys and relations.
For example, you might have a movies database. In it, you store information about the Movies, Studios that released the movies, and the Actors in the movies. Each of these becomes a table. Each Movie is released by one Studio. Since you don't want to store duplicate the studio information (address, etc) in each Movie entry, you store a relation to it, so each Movie item contains a reference to a Studio item. This is called a one-to-many relationship (one studio has many movies). Likewise, you don't want to store Actor information for each Movie. But one Actor can be in many Movies, so this is stored as a many-to-many relationship.
Learn SQL itself. SQLCourse is a good place to get started, but there are many other books and resources. SQL is a standard, but each RDBMS has its own vendor-specific ways of doing certain things and other limitations (for example, some systems don't support sub-queries, there are several different syntaxes for limiting the number of rows returned, etc). It's important to learn the syntax for the one you're using (eg, don't learn Oracle syntax and then try and use it in MySQL) but they are similar enough that the concepts are the same.
Tools depend on the DBMS you use. MySQL is a pretty popular database, lots of tools are available, and lots of books. SQLite and Postgresql are also quite popular, and also free/open-source.
If you can, you really want to find someone who knows how to use it, and pick their brains. That's because there are a lot of important principles (eg 3rd normal form) which will are a lot easier to learn through discussion rather than from books.
If you want to teach yourself, you should learn the syntax for doing basic selects, joins, updates, deletes, and group by queries. You should also learn the "Swiss army knife" of selects, the CASE statement. Too many people don't. Many of the tutorials recommended in this thread will do that. Then you need to try to solve SQL problems. I'm sure that Joe Celko's SQL Puzzles and Answers is a good source of them, though it may be a little advanced.
This will let you actually write SQL. But you still need to learn how to organize a database. Which for most purposes means that you really need to learn what 3rd normal form looks like. You don't have to be able to give a formal definition of it, just recognize it when you see it, and know how to adjust something to be in that format.
Lots of references will explain it, but you won't know if you're reading them correctly. This is where it really, really helps to have access to someone who can look at a table layout and tell you, "That's right" vs "That's wrong, here's what needs to be changed." Failing all else, you could post a question here with a proposed layout. But a back and forth discussion with a live person would still be preferable IMO.
Try Wikipedia, http://www.w3schools.com/sql/default.asp and http://www.sql-tutorial.net/ Also check YouTube for SQL Videos.
You are correct, SQLite is a great place to start because it is free, lightweight, and available on many platforms. This is only a start though. SQLite is very liberal on SQL syntax and lacks an intneral programming language like DBMS systems have. Still, if you want to start and learn with minimal overhead, SQLite is the way to go.
SQLite is nice and they have really nice documentation, however you should be aware that it is not a full featured SQL database like MySQL, Postgres or the commercial variants. SQLite's API relies on callbacks which is a fine model, but not all database APIs work that way. If you are familiar with Perl, then DBI is another nice way to explore SQL.
/Allan
"A Gentle Introduction to SQL" - You can even practice "live queries" right on this tutorial website.
http://sqlzoo.net/
I always recommend The Practical SQL Handbook for a good starting point for beginners - especially those who have seen SQL but never understood how to build up a query them selves or how they work.
All Celko's books are great.
Hernandez's Mere Mortals book is good.
Ken Henderson's books are also excellent.
Reading up a bit on relational algebra is a good way to understand the underlying concepts of relational databases.
Jeo Clecko's SQL for smarties is excellent.
I recommend the exercises at this site: sql-ex.ru
You can even get a certificate if you do the right.
Start with Ideone and try queries on line just with a web browser.
If you program using the .NET framework, then learning LINQ might be a good place to start. The LINQ "engine" will handle the back end communication with the database (or objects, or entities, or XML, etc.) for you. If you want to dig deeper, you can explore the SQL generated by the LINQ that you write.
If you already know a thing or two about web applications, then that would be a good place to start. Nearly every serious webapp uses an SQL database as its backend.
The folks at Head First have come out with a book. Going by how good their other books are, I'd recommend this one. Haven't read it yet though. (LINK)
You may want to consider starting with MySQL as it is widely documented and very easy to get started with. You can download the Community Edition and then add the GUI Tools and you'll both GUI and command line interfaces.
Read a book to start learning about SQL. I read Beginning SQL Queries from Apress not long ago, and found it clear and logically written for a beginner (I reviewed it for a colleague).
I learnt 90% of what I know about SQL from here. In 1997.
I think it still stands up.
Hey although not complete it's great to get hands on with SQLite as mentioned above, Google 'Learn SQL the hard way' and there is an online book which you can work through which uses SQLite.
Google is great for downloading pdf's for free 'Cough Cough' but try http://www.sqlfiddle.com/
It's an online platform which is free! No log in required just go to their page, create your database in whichever language you want (That's the best bit I choose T-SQL as I'm learning that), and then you can query it as much as you like. I'm learning with a pdf file which has opensource SQL files you can download to follow along, and SQLFiddle has been great to learn vendor specific SQL.
Related
I apologize in advance if this question seems silly, but I'd really appreciate some help. I want to learn SQL, but I don't want to do so by learning how to query databases in "fake" environments (e.g., through courses or simulated database environments). I want to do it the "real" way, but because I have no experience with databases, I don't know how exactly that's done.
I heard that PostgreSQL is a widely accepted RDBMS. So I went ahead and installed it. But it seems it's quite technical, and there aren't many tutorials on YouTube on how to, say, get access to a database and just query it.
I want to know how I can play around with real databases in a sort of "sandbox" environment like this. Where would I start?
I've been spending a considerable amount of time learning MongoDB as part of the MEAN stack (I'm new to the MEAN stack), and I feel like I'm just barely starting to get the hang of it. Recently, however, my supervisor at work (who's an experienced programmer) suggested I learn relational databases (it could be that it's used by more companies), and I have taken his suggestion to heart since I'm only a junior developer, and would like to move up soon. My personal goal/project is to build a social networking site where one group of users have the ability to search for another group of users (and most likely charge a membership fee). Would the database matter for a project like this? I would love to kill two birds with one stone by learning something (and learning it really well) that could be used in my personal project, and in a professional job.
I'm certainly open to learning more than one language, but I need a starting point, so I need something that will help me accomplish my personal goal. Since I've spent a considerable amount of time with JavaScript (as oppose to, say, Python), having to learn relational databases concerns me. Are there any downsides to just sticking to MongoDB?
Thanks in advance!
The first thing you need is to assess what type of data you are going to deal with (will it be structured, easily represented by tables, or it will be more of the non-structured type).
If structured, RDBMS is the way to go.
Incidentally, as far as I know, the first versions of Facebook were implemented using MySQL (the type of DBMS your boss was referring to).
Farid, as you're a junior programmer, I'd suggest you to learn as much as possible of both approach.
The knowledge acquired on one of them will also help you getting the most from the other (as they both concern data, how to structure it and how to query it).
Also, in the day by day job (unless you specialize only in large sites where scalability is the first concern) you might encounter RDBMS more frequently than NoSQL choices.
Both technologies have pro and cons and, unless you know both sides (at least documenting yourself, if not by direct experience) you might go for one solution when the other could have been preferable.
Well, anyone have concern about learn SQL (and use JOIN), but:
One day, you don't know how, you will use it (or understand it), so perhaps is better take a moment for SQL (it's the most widespread)
MongoDB is good if you development a REST service, but if you want make a social network like project, perhaps is better look at Graph database.
Perhaps that video can help, is an overview of SQL vs NoSQL.
I am a beginner but know the basics and am peering into more advanced data mining and stored procedure routines. I have learned small concepts that mimic C# Design Patterns such as looping structures but have not seen much (on the web) about SQL Design Patterns.
I ask because I ran across this book http://www.amazon.com/SQL-Design-Patterns-Programming-Focus/dp/0977671542 but have also always been told that you will find better information on sites like Stack than in a book.
I've been told that for programming professionals Design Patterns are a must. Is this also the case for SQL programmers?
*(Wasn't sure if this belonged on Meta or not. It's not a question about the site but is a general discussion question)
Design patterns for SQL are very useful as well. Is it any good to gather data if you do not store it properly and retrieve it back to make useful decisions?
I have found Joe Celco's books very useful on database design patterns. http://www.amazon.com/Joe-Celko/e/B000ARBFVQ
Of course you should read books. In the first place they tend to be written by people recognized for their expertise (not just anyone who happens to log into the site) so the information is likelier to start out as more accurate. Then they have editors who help make the presentation of the information better. Finally a good book should discuss in more depth than an SO post can do and thus you will get information at a deeper level than just the code to fix your current problem. This means your understanding will grow and you will know why you would do X vice Y and be able to expand that understanding to new problems.
DBAs who don't read books probably don't understand the internals of how the database works very well and are likely to be less effective than those who do read in depth about their profession.
A book I recommend is:
http://www.amazon.com/SQL-Antipatterns-Programming-Pragmatic-Programmers/dp/1934356557/ref=pd_sim_b_1
Also books on performance tuning are critical to read if you want to use good patterns in your SQL. A huge number of performance problems are caused by badly designed SQL. YOu should know what works well and what doesn't. Those tend to be databse backend specific, so look for ones realting to the type of databases you support.
I am relatively new to using SQL Server (we're on 2005) but not to database design, creation, and programming. I have decided to use TSQLUnit for the testing we want to do, and have been learning it as I go. But, there are some things that have not become clear over time, and it gets pretty frustrating to want to do a particular type of test and not be able to do it. I'm not sure if the problem is with SQL Server (very unlikely), TSQLUnit (unlikely) or me (very likely).
Does anyone know of an online resource or community of TSQLUnit users that I could consult? I would like to both contribute when I can and gain benefit when needed.
Any suggestions or links will be appreciated.
There are so many
SQLBangalore on Facebook.
Even you can post questions in SQlcetral as well.
Sorry to ask this kind of questions.
But I am eager to know some good sites where I can have the opportunity to have some sql competitions.
I found 1
TroyK's T-SQL Challenge
but it is not free.
I am looking for a free one.
And also C# programming competitions. One I found is Code Chef
I am Looking for some more.
Also, it should be for any ages!
Edited:
I liked Project Euler. It's nice
Also some TSQL programming challenge. Sql Server Central is good. But I am looking for more TSql programs
Thanks in advance
For C#, Project Euler is a good one. It is not C# specific as answers can be submitted in any language. The challenges tend to be quite challenging as they are not just about solving the problem, but solving it quickly.
For SQL, SQL Server Central publishes some PDF books called SQL Server Stumpers, as well as having SQL challenges every now and again.
http://www.topcoder.com/ has regular programming competitions for multiple languages, c# included.
Well, you can do TroyK's challenge without registering for EE. Just see whether the desired result equals your result.
This way you cannot compete with others, though.
Unfortunately I haven't seen any SQL competitions but these are some of the resources we used in the FIU Programming Team:
http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8 was the official website my university programming team used to hone our skills. They accept answers in various languages, but the focus is more on your algorithms than your syntax.
For some softer stuff many FIU students used http://codingbat.com/ which also accepts a few different languages. Many of the problems on this site were simple and straightforward, the challenge came in trying to code them as fast as possible.