I am starting to learn Node.JS and being an old school developer I grew up surrounded by SQL.
Now I have read that NoSQL (specifically MongoDB) is the perfect companion for Node.JS and so I was asking myself if use Node.JS with relational databases may be considered conceptually wrong.
Or better asking, I HAVE to use NoSQL database with Node.JS or it will depend on the characteristics of the application, meaning that I can freely choose between SQL and NoSQL depending on what will be better for my project?
The point is that I have a small desktop project about to start with and it would be the perfect chance to practice Node.JS but since it's a project that is going to be actually used by someone I wouldn't like to figure a bit further that it was a wrong choice. The project in question is based on simple tables containing customers, products and orders. Opinions?
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 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.
I am trying to help a small business that has an application that could benefit from occasional (or temporary) database expertise. The problem is, this company has all their IP in this database, so they are rightfully hesitant to give someone access it.
They would typically meet and gain trust in person, but the talent pool within physical proximity to them is pretty limited. I would like to think that they could still somehow tap into the global DBA expertise though...
Even the crappiest DBA will be able to dance SQL Circles around these guys - so exposing only pieces of the database doesn't sound feasible to me, but I am hoping I just don't know how.
Anyone have any tips on how they could find a trustworthy company (or individual)? When I hire a programmer, I start them on basic stuff that if they mess up won't hurt too much. With a database, is there something that I can start with that can limit their exposure. Maybe Profiler output for analysis or something?
As the others have mentioned, NDA's are a good idea, that covers you from the standpoint of WHAT they see...
However, I can feel that you are also concerned about any potential "damage" the person could do to your database if they make mistakes. To get around, and protect from this is a bit harder, but there a few good key items that I would recommend.
BACKUP EVERYTHING before starting, this is common sense, but cannot be overstated
Provide the consultant a test environment if you are able to replicate production issues. This gives an isolated environment where testing can be done.
DO NOT limit their database access. Database issues require digging into the system, limiting their access, could actually contribute to an error rather than preventing them.
Look for references, or evidence of the persons abilities.
I provide this information as a consultant myself. I do .NET and SQL Server consulting, and I ensure that all of the above are true in my consulting cases, and I have not had a fault. Steven points out the biggest key in this all and that is all a consultant has is his reputation. Serious consultants fully understand this, and because of it will make sure that they do NOT put themselves into tricky situations.
The simplest thing is requiring all employees and contractors who see the database, or its design, to sign non-disclosure agreements. There are plenty of boilerplate ones there, and a good attorney can provide guidance on what you'd need in one with less than an hour of billing time. Everyone in the industry is used to them, and everybody understands why they have to sign them.
Of course, that's not a programming question, it's just a legal problem.
consultants sign NDAs all the time, and the good ones take them seriously because a consultant's reputation is all he has
while not a DBA, i can highly recommend this fellow as I have known him all my life ;-)
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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.