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SQL Fundamentals
This beginner book takes a traditional look at the ever-popular Structured Query Language. Never bothered to learn SQL? Here's your chance. SQL Fundamentals, by John Patrick, takes the first layer of SQL in Access and Oracle [robo, I find this a confusing phrase, not sure how best to recast, but somehow] and sums it up in this 834-page manual. Read more for SQL Fundamental's strengths, weaknesses and everything in-between.
The Basics SQL Fundamentals discusses the practical realities of extracting information from a database. Patrick shows the reader how to use SQL in both Oracle and Access. The book starts with a brief overview of the roots of SQL and relational databases; after this introduction, the book covers select statements and the basics of a query. Each chapter builds on the next, and the book follows a simple progression, adding complexity as it goes along.
This book is a very easy read -- it flows much better than a textbook, yet still conveys the information it promises. However, it's definitely for newcomers to SQL. So, if you have any experience in SQL this would not be the best choice. (Chapter 1 explains the concepts of a cell, row, column, and table, which might be enough to let you decide if this book is at the right level for you.) Throughout the book, the author relies on applying each newly introduced concept to a single relational database example. This hypothetical database (a table of employees trying to calculate their meal credits) makes the book feel consistent, and helps eliminate confusion about where the example information comes from, but it's also limiting for readers who want a broader range of examples.
One of the greatest strengths of this book is its wealth of code examples and accompanying tables. In contrast to many other manuals, this book illustrates queries along with their effects on the tables. Other SQL books (ones I consider going up to "layer 2" SQL) have many example queries, but some of them fail to show any sort of results from their example tables. Also, much of the code in SQL Fundamentals is well documented, with footnotes explaining any changes that occurred.
Caution: Beginner Book The book is called SQL Fundamentals. However, in this case, the fundamentals are only as they apply to the Oracle and Access databases. It mentions the existence of other distributions at the beginning of the book: "Oracle, Access, DB2, MS SQL, Informix, SQL Windows, Sybase, SAS sql procedure, FoxPro, dBase, Tandem SQL, MySQL, SQLBase, Cold Fusion, SAP, Business Objects, ODBC, Ingres, Ocelot SQL, OsloData, PostgreSQL, Rapid SQL, XDB, SQL/DS, Mini SQL, Empress, Interbase, Progress, Supra, SQL Report Writer, Paradox, Delphi, VAX SQL, Essbase, Beagle SQL, GNU SQL Server, Just Logic/SQL, PrimeBase, Altera SQL Server, DataScope, and PowerBuilder." However, Patrick never speaks of them again; perhaps he should re-title this book SQL Fundamentals: Applied to Oracle and Access? Readers considering this book should keep this in mind. The book explains things well, but the book's overall logic is geared toward those using one of those databases, and the examples are relevant only in that context.
I primarily use MySQL and Progress, so a book explaining SQL fundamentals applied to Access and Oracle isn't going to help me unless I specifically take on projects which use these particular databases. Also, The book often goes into unneeded repetition of subjects: for instance, the first 150 pages are all about select statements. I've never seen so many select statements picking apart one table. I personally think it would benefit from being trimmed down, and leaving further study to the reader.
The Plug I would recommend this book to a newcomer to SQL. It covers the fundamentals just like it claims. After finishing this book, you will have a grasp on things ranging from the most basic select statements to unions, self joins, & cross-joins.
Something to consider might be what SQL database you will be working with. If you'll be working with either Oracle or Access this book will be helpful. If not, I suggest looking at things like Managing Using MySQL by O'Reilly.
Finally, from the text comes this concise answer to the question "Who Should Read This Book?"
Everyone with an interest in getting information from a database can read this book. It can be a first book about databases for people who are new to the subject. You do not need to be a computer programmer. The discussion begins at the beginning and it does not assume any prior knowledge about databases.
That seems like a fair summary; with the caveats already mentioned, I can recommend it for newcomers to SQL looking for a thorough but not patronizing introduction.
You can purchase SQL Fundamentals from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
When the SQL to this book will be out? Har de har har har.
Error: Erection reset by beer.
How big is the typeface? I mean, come on, it's not that big a language after all and you could easily fit the basics into 50 pages at most...
Code, Hardware, stuff like that.
Do you pronounce it Sequel or S-Q-L???
/. poll!
To me it is Postgres-Q-L and My-S-Q-L, but I think the Microsofties call it Microsoft Sequel Server...
Maybe good for a
If you need to expand your SQL to include PostgreSQL, try:
PostgreSQL: Introduction and Concepts by Bruce Momjian
Practical PostgreSQL, by Command Prompt, Inc. written by John Worsley and Joshua Drake of Command Prompt, Inc.
Very practical definitions, examples, and procedures. I'm still scratching the surface of SQL, so I haven't found anything yet these sources can't handle.
I've also found the Usenet Posgres groups useful.
JA
http://www.johnalex.org/
Something to consider might be what SQL database you will be working with. If you'll be working with either Oracle or Access this book will be helpful. If not, I suggest looking at things like Managing Using MySQL by O'Reilly.
I would suggest not, because you will learn bad habits, and they will be hard to shake once you start working on a real database (Oracle, Sybase, SAP-DB, etc). I have seen MySQL programmers do massively inefficient (and stupid) things like retrieve a list of keys from one table, store them in an in-memory array, then loop through the array executing a select for each key in another table - because they didn't know about subselects. I've seen them put all sorts of redundant validation crap in the middle tier because they didn't know about constraints and triggers. I could go on and on...
If you want to learn SQL, you first need a solid general foundation like this (I have an earlier edition) then later study the extensions that each vendor provides (Oracle PL/SQL, Sybase T-SQL, etc).
With OS X came a bundling of MySQL, and CTOs (Chief Technology Officers) across the country thought to themselves that "Hey, if a big profitable company puts this package of OpenSource software into their flagship OS, it must be OK to use. Let's stop dishing out tens of thousands of dollars a year to Oracle and let's just use this free RDBMS implementation. (Sure, PostreSQL is a bit more weathered, but both are pretty nice considering their price).
Wider acceptance of MySQL and its related products/technologies is a good thing, and books such as this are only a good thing in my mind.
If you celebrate Xmas, befriend me (538
about the book:
It mentions the existence of other distributions at the beginning of the book: "... and PowerBuilder."
I know I stopped using PowwerBuilder with the version 7, and the version 9 is out, but at that time, it was not a SQL database, only a client for SQL databases.
about SQL:
SQL is a langage with which it is really easy to obtain a result that is not what you intended.
It in fact is Postgres-Q-L and My-S-Q-L, but you use "sequel" to query both of those. I haven't seen anyone in a long time pronounce the language name S-Q-L, the names of the two products you mentioned are dictated by their respective developers, so it's a different matter. (incidentally, I'm as far from a Microsofty as it gets)
sic transit gloria mundi
AFAIK almost everyone says sequel, not just M$ites. What really has me wondering though is, is it Lynnucks or Line-ex and how do you say that Bjarne guys last name?
When I first started making dynamic web pages, I used access. I used acces for various reasons. 1. It was on a computer at school. 2. I was running win 98 at the time. Not many good databases will run with 98. Even though I wanted a database to keep track of things, I only had one option.
Even though I layed out the database in access, I didn't touch access after the file was created. I then moved to personal web server (an all the security holes that creates) to manipulate the database through ASP.
I know there are many others that because of various reasons are unable to get their hands on other databases, if you get the fundementals of sql through access, you are able to understand the majority of sql statements having to deal with other databases. Even though,things do differ, you have somewhat of a foundation to understand sql.
It's Microsoft Squeeeeeal! Server (say it in your best deliverance voice )
Todd
---- "If we have to go on with these damned quantum jumps, then I'm sorry that I ever got involved" - Erwin Schrodinger
I think the SQL in a Nutshell is a great resource, but if you're just starting with SQL this sounds like a decent book, would be nice to have a comparision though. I've lost track of how many times I've had to explain what the first chapter covers (cell, row, column, table, etc). Maybe I should keep a copy around just to loan out in such cases. "Go read chapter one and come back later, then try tell me what you want done."
PS: Amazon has it for $34.99 [associate]
Actually for most /.ers you would get a nice fat result set back, however, you'd be forced to do an inner join with the "LikelyToBeInterestedInASlashdotReadingNerd" table and then you'd get no results.
sPh
SELECT Amazon.Price FROM Amazon WHERE Amazon.Price < bn.com AND Amazon.savings = 12.50 [aff.]
Save some money
sPh
Quick way (internet) Step 1: go to mysql.com and download mysql
Step 2: go to google.com and enter:
+mysql +sample
Step 3: Spend some time reading, figure it out.
Standardized way (book) The advantages of a good book are mainly in the way of standardization and security. While I've seen books that were crap in reference to this, most do a much better job of providing code samples than the underinformed indivuals writing "samples." That being said, major sites like Zend.com and php.net still provide good examples etc, but in that case you need some fore-knowledge to know what to look for.
All IMHO of course. Many of us are "example learners" as opposed to "book learners".
If you want to make the developers/DBAs/bosses in your company think you are an absolute god, get a copy of Celko's SQL Puzzles and Answers.
Typical view error...
CREATE VIEW girls AS SELECT * FROM slashdot WHERE sex = "F"
... returns an empty set iteself, so your subselect isn't going to do you any good, naturally.
Actually, usage changed sometime around 1994
I think it started happening before then. I was doing SQL stuff back in the 1990 timeframe (even interviewed at Ingres and Sybase) and everyone I knew was saying sequel even back then. It might have been a Bay Area thing though, or maybe even specific to the "upstart" db's, don't know what the IBM or Oracle camp was calling it.
There is an element to database design that is a subfield of calculus. Just learning the syntax for CREATE TABLE and SELECT doesn't really get you very far. Understanding why relational sets are powerful, and being able to leverage that power to problem solving ends, is a far bigger learning process than simply understanding the syntax of SQL.
In order to fully comprehend, say, the works of E. F. Codd, one really needs a background in automata and in abstract algebra.
If I wanted to learn the theory behind designing databases what would be a good book to read? I'm thinking more along the lines of learning from a text book v.s. learning from The Blithering Idiot's Guide to Database Design.
Chris Kuivenhoven is a thief, beware
It in fact is Postgres-Q-L and My-S-Q-L, but you use "sequel" to query both of those. I haven't seen anyone in a long time pronounce the language name S-Q-L, the names of the two products you mentioned are dictated by their respective developers, so it's a different matter. (incidentally, I'm as far from a Microsofty as it gets)
It is properly S-Q-L because Sequel is something different (Structured English Query Language, an IBM project that never went anywhere). But the term "sequel" for SQL has come into common use, so it's the de facto pronounciation.
Microsoft people just call the product "SQL Server" which IMHO is like calling Windows "Operating System" but it comes from the old days when Sybase and Microsoft cooperated (circa MSSQL 4-6/Sybase 10). Sybase's product was called "Sybase SQL Server", but people just call it "Sybase" (akin to calling Windows "Microsoft"). When they split, MS kept the rest of the name.
You can easily spot a hardcore elite database guru by the fact that these people pronounce it "squirrel".
Does anyone else find their choice of databases funny? I could see MS SQL & Oracle, but aren't Access & Oracle two totally different beasts?
Access is for small db's, usually personal ones or very small business databases. Oracle is a big enterprise database capable of storing huge amounts of data.
Isn't that kind of like writing a book teaching you an introduction to writing batch files and mastering C++ all at once?
"Linn uks" would be the closest American accent equivalent. In Torvalds' accent, it's "Leen ooks".
I here you. I always get confused with 'C'. Is it pronounced "See"? Or as I like to refer to it: "C".
My coworkers like to read the "Fack" when they need help. If people ask me, I just tell them to consult the "Fa" "Q".
I don't have a sig...Do you??
First of all, you do have a point. SQL isn't a big language with a lot of features, but if you had really spent a lot of time working with SQL, you would know that SQL is a language usually implemented with A LOT of nuances, and that many problems that are easy in procedural languages that take a lot of work with SQL.
SQL is a powerful tool, but solving many problems with SQL can be very daunting at times, especially when you're dealing with vendor specific nuances.
"Communism is like having one [local] phone company " - Lenny Bruce
Actually, in 93 I heard quite a few people calling SQL "squeal".
Best Slashdot Co
With OS X came a bundling of MySQL, and CTOs (Chief Technology Officers) across the country thought to themselves that "Hey, if a big profitable company puts this package of OpenSource software into their flagship OS, it must be OK to use.
Yes, the mindset of the fortune 500 lives or dies by what Apple does. "Hey I wouldn't buy any of their overpriced computers but if they think MySQL is great, it must be".
MySQL is pretty good though. Ah hee ah hee hee
I am not a number! I am a man! And don't you
Go to bookpool.com to save money, click on the Slashdot link, if you want to help Slashdot...
Wow! Oracle and Access mentioned in the same sentence without sarcasm or outright laughter. Someone please note the date and time.
--an unbreakable toy is useful for breaking other toys--
> Error, column SexLife does not exist in this table.
/^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$/i
It's always pronounced S-Q-L. However, Microsoft (and Sybase) call their product "Sequel" Server. You see, Microsoft "Sequel" Server is basically the brand name of a satabase server that uses S-Q-L, in the same way that "Orace Enterprise Edition" is the brand name of a database server that uses S-Q-L, or "Apache" is the brand name of an HTTP server.
So, it's correct to refer to Microsoft "Sequel", as long as you understand that you're talking about the product, and not the language.
Slashdot is jumping the shark. I'm just driving the boat.
It's being added to the current dev version but not in production versions.
I've been reading that same statement for about 2 1/2 years. You can expect a subselects in MySQL at about the same time you'll see Duke Nukem Forever under your christmas tree -- in other words, "real soon now", for sufficiently ludicrous definitions of the word "soon."
Slashdot is jumping the shark. I'm just driving the boat.
I've seen them put all sorts of redundant validation crap in the middle tier because they didn't know about constraints and triggers. I could go on and on...
Validation logic belongs in the middle tier. The storage tier is just that - storage. It shouldn't be smart, and it very definitely should do anything else than storing the data I tell it to store.
Triggers, constraints - bah. All very vendor specific and they lead to application logic being strewn all over the tiers. Application Logic should be in the middle tier, period.
-josh
I pronounce it "squirrel". I worked in a place where everyone said "sequel" and I hated that name. The strange thing is, I don't know why. I just did.
Don't label something "offtopic" unless you know the topic well enough to tell what's on topic.
I have found http://www.dbdebunk.com/ very informative. If you insist on cutting down trees, I would recommend any of the books that this site links to.
There are fundamental problems with SQL. You may well be forced to work with it but you should at least know what its limitations are.
Hopefully, once you truly understand the problems with SQL, you will see the light, rebel, tell Oracle et al to go screw, and help develop some nice good Open Source alternative to the crappy SQL language.
If you disagree, you are welcome to touch me lower.
When my mom calls me and tells me she's having problems with her "microsoft", it takes an additional 10-20 minute to figure out if she's talking about Windows, Word or Outlook...
I have found http://www.dbdebunk.com/ very informative. If you insist on cutting down trees, I would recommend any of the books that this site links to.
There are fundamental problems with SQL. You may well be forced to work with it but you should at least know what its limitations are.
Hopefully, once you truly understand the problems with SQL, you will see the light, rebel, tell Oracle et al to go screw, and help develop some nice good Open Source alternative to the crappy SQL language.
If you disagree, you are welcome to touch me lower.
Dear Slash-Dotters,
I can't believe how clueless you guys are. Everybody knows it's Structured QUERy Language, or
SQUERL, which is properly pronounced _SQUIRREL_.
Sincerely,
Steve
If you watch TV news, you know less about the world than if you just drank gin straight from the bottle.
hahahahaha... After 10 years of doing development, all of it with databases in the back end, I know people like you very well. People who don't understand databases don't know how to use them, and code all of the logic into the middle tier. Very typical. It leads to horrendous bloat, very poor performance, and occasionally, complete project collapse. In one case that I was involved in, the company closed because their project couldn't be done on time since they decided to listen to this "expert" who spouted off similar stuff like what you're saying. The project became an OOP mess that was impossible to debug and maintain. More importantly, performance was never acceptable, so the project and the company died.
Databases, especially "grown up" ones like Oracle and DB2 are designed and optimized to do a hell of a lot more than data storage. If you want storage, use flat files. You should maybe, I dunno... pick up a book. You can write entire applications in nothing but PL/SQL that perform several times better than a similar C++ or Java app.
In fact, so much development is done in the databases themselves, that Oracle has a certification just for that, called the Oracle Certified Application Developer. But alas, generally these days everyone is still running around screaming "middle tier! middle tier" while the real database gurus just sit back and laugh as projects implode.
How is this a beginner's book? A much smaller book will do. Maybe K&R should write one.
love is just extroverted narcissism
I refuse to give money to companies that try and make me feel like an idiot.
Al Qaeda has ninjas!
Oracle has a problem with Joins, they just don't work, and that's a big bit of SQL.
ROTFL. Oh jesus... hang on, I gota wipe the tears from my eyes. Oh christ, that needs to be modded up to +5 ignorant/pathetic/funny.
Joins in Oracle don't work? You're saying, Oracle, the oldest database on the market, the most widely used, made by he second largest software company in the world, doesn't work. You have got to be off of your fucking rocker. I can't even begin to argue with a statement like that, because you can't argue with people who are so delusional, that they can't possibly see the truth. That's like when some crackpot on the street walks up to you and says, "The sky is red and filled with demons!". How do you argue with that other than "no it isn't"?
In the immortal words from Billy Madison:
"Mr. Madison, what you've just said is one of the most insanely idiotic things I have ever heard. At no point in your rambling, incoherent response were you even close to anything that could be considered a rational thought. Everyone in this room is now dumber for having listened to it. I award you no points, and may God have mercy on your soul."
People who don't understand databases don't know how to use them, and code all of the logic into the middle tier. Very typical. It leads to horrendous bloat, very poor performance, and occasionally, complete project collapse. In one case that I was involved in, the company closed because their project couldn't be done on time since they decided to listen to this "expert" who spouted off similar stuff like what you're saying. The project became an OOP mess.... [emph. added]
./ topic), but the proper solution is NOT to write your own database and index managers from scratch. If you want to get out from under the DBA's thumb, then try some other approach besides using arrays for indexing and manually-written joins.
It seems that many OO fans have a desire to create their own "database" from scratch via programming code, and treat the RDBMS as mere "persistence". They end up using array-like things to manage their own indexes for one-to-many and many-to-many relationships, for example.
This is a widely accepted practice in the OO community. I really don't want to maintain such code.
It seems many OO fans want "control". If you use the database for such things instead, then you are more dependent on the DB vendor and DBA's, and that bothers them.
I agree that DBA politics can be a bottleneck for developers at times (would make a great
(Note that I did *not* say that *all* OO fans avoid or mis-use databases. I am only saying that it is too common a practice. Thus, I am not really bashing OO here, but a bad practice often found in OO shops, for whatever reason.)
Table-ized A.I.
I would like to see SQL overhauled. It could be replaced with a functional-like syntax (FP) where you reference stuff instead of only nest it. Nesting gets really messy for bigger stuff because it splits "lists" in halfs and separates the halfs by jillions of miles. Plus, you cannot reference repeating sections in SQL without writing views, which requires bothering the grumpy DBA.
A functional syntax would also allow one to add extensions without worrying about ruining the parse tree. Thus, if Oracle had something that Sybase did not when you switched vendors, the DBA could write their own library function to match it. A shop can't add to SQL very easily on their own because of the complexity of the language. FP syntax is more modular.
The longer we wait, the more SQL will become entrenched, due to books like this.
Table-ized A.I.
"Beginners" guide should really be these three lines:
To select something
select columnname1, columnname2 from tablename where columnname1 = 'thevaluetogetby';
To add a line to the DB
insert into tablename (columnname1, columnname2) values('value1', 'value2');
To update a line
update tablename set columnname1 = 'value1', columname2 = 'value2' where columnname1 = 'thelinetoupdate'
THAT is a beginners guide. I don't know what the other 833 1/2 pages have... Sure some people consider all the different joins to be "beginner" but I'd call that stuff intermediate.
Travis
I'm gonna make this server squeel like a pig.
There is nothing so silly as other peoples traditions, and nothing so sacred as our own.
No, no, no... how do I say this? NO!
The OP is completely correct: triggers and such are rubbish (except to enforce data integrity when the integral RDBMS mechanisms cannot). DBs are for storage, period. You claim that a DB is a great place to shoe horn logic, but that leads to problems.
1. The bloat is in a functional-programming layer (SQL) instead of a procedural/OO layer. Given a choice between lotsa logic down in a DB and lotsa logic in my app, I'll take the logic in my app any day of the week. SQL does not promote code reuse, whereas most procedural and OO languages do promote it to some degree.
2. The more code you put in a DB, the less portable your schema is -- and I'm not talking about platform portability, I'm talking about RDBMS portability. Nothing is worse than [IBM|MS|ORA] database lock-in.
3. The poor performance you site may be common in your experience, but code in the middle layer(s) is not the cause of that: bad design and poor testing are the causes. Don't confuse correlation with causation.
These points are backed with experience: I've been programming for 15 years, 7 years of that using databases heavily. The company I work for now has terabytes of data stored in the schemas I've developed for my apps, and no one has ever complained about maintenance or performance on one of my designs.
Heh, Windows is called Windows, as in "Windowing System" - not much better than "Operating System" if you ask me.
sic transit gloria mundi
Year, right. Next after 5000 hours. Even professional SQL programmers keep doing serious mistakes in sub-queries. Not only in performance optimization area (waiting for results forever), but also in consistency are (getting unexpected result sets).
When you have 2-3 tables with 1-2 foreign keys than you may learn sub-queries in 12 hours. But when you do a very specific data mining work, combining several huge historical journals, several classification graphs, lots of assotiation maps and many lots of lookup tables, then you might realize that you still have to learn SQL even after 5000 hours of using it. If you don't think so, then you've never done any serious data mining by yourself. I spoke with many SQL programmers who worked with ERP, CRM and Supply-Chain applications and they had the same opinion.
Less is more !
thank you !
I was waiting for someone to point out that the given example of a subselect is really just a simple join. That's really just SQL 101. Now, there are cases for subselects, but they do get hairy.
btw - middle tier all the way - what do you do in sql when you want to say, check db value a, based on return of C function b? run home to mom that's what.
middle tier promotes code re-use, but it also promotes a _logical_ data schema over the _physical_ data schema which is exactly what putting logic in things like triggers and such in does not do.
Having redundant, or seemingly ludicrous table structures can sometimes be the fault of client specs changing under a programmer/designer's feet.
;-)
I recently completed an app to handle load allocations for a haulage company. A weeks worth of deliveries are emailed over every Saturday, the app sucks it in and populates the db, then makes descisions based upon vehicle availability, capacity etc etc. This was all well and good UNTIL the supplier started reusing distribution point IDs as they changed! So one week we would have ID 65536 holding details for Fred Bloggs, the next, ID 65536 would be Joe Smith. This brilliant idea of reusing IDs was never mentioned, and only appeared after 2 months had passed and problems arose with deliveries appearing at the wrong addresses!
When asked why they did this, the reply was "we just do it that way"?! Needless to say, since the distributor IDs were the foreign key for orders, which were in turn linked to delivery items, and also to the vehicles used for delivery, this lead to some "creative" changes in the db (now delivery points have the id plus another "version" id which doesn't help efficiency all that much, and must look ridiculous to anyone else viewing the code).
Then there was the fact the haulage company wanted to be able to "squeeze" extra items into a vehicle after specifying its maximum capacity - and then asking me why the app wouldn't allow it - oh and also they often wanted to be able to route large vehicles to locations marked as "inaccesible" for that vehicle - which kind of screwed up the routing logic... In fact, just thinking about that project brings tears to my eyes
Code, Hardware, stuff like that.
Sure, this book will help you learn SQL syntax (maybe they ought to have named it "SQL-Primer Plus") and elucidate the schemas found in your favorite LAMP (linux, apache, mysql, perl/php/python) guides, but how will this help teach people the fundamentals of good database design? Sounds like this book will just churn out even more people who can just add "I know SQL and how to build databases" to their resume even though they will give you a blank stare when you ask about normalization. Like how using MySQL for 'learning' purposes leads to bad habits, I fear that this book might also promote loose discipline in web-based-database-applications. If I am contracting someone to build me an ecommerce site and know they have read this book, they won't be hired.
there's a middle ground between all or no logic in the "storage layer"
of course. brilliant observation.
tables thems selves contain application logic
not my tables, and not any tables from the developers on my team.
checking row types, etc.
this isn't application logic, it's data integrity.
"hey, you're using that querry quite a bit, how about we just compile it all up in the database for you and speed things up a bit, eh?".. bang, code reuse.
sorry, that's not code reuse at all, not even close. give me a [stored proc|view|table] that i can inherit from or subclass, and that would be reuse.
but those who spend 500,000$ for their RDBMS software package will keep it around for a tad.
and one of the reasons that they'll "keep it around" is because they paid so damn much for it. why lock in an implementation decision for so long? it doesn't promote agility, nor does it promote flexibility. quite the opposite, it encourages poor SQL coding (i.e., vendor-specific features). it's called the "Golden Hammer" Anit-Pattern. look into it.
most companies have terabytes of data stored in their schemas
um, no. gigabytes, maybe, but most companies have databases in the terabyte range? i don't think so.
you might find that if you take out all those i's and use lots of we's for the good of the compnay, you'll still get some credit
funny, it sounds as if you haven't read _The Mythical Man-Month_, wherein Brooks asserts that the best software systems come from a single mind. if you're a professional software developer (it's hard to tell from your post), i strongly suggest you read it.
as to credit, i'm not in it for that. rather, what motivates me is implementing solutions that help achieve the objectives of the company for which i work. see, i'm a stock holder as well as an employee, and i'm just as motivated by profit as the CEO.
on another point, maybe should note that a great sense of ownership leads to pride in work and higher quality. (to be sure, there are pitfalls associated with too great a sense of ownership, but experienced developers know when and how to cut the cord, so to speak)
No need to respond to my linux or bjarne comment, I was joking, I've heard the pronunciations, please, stop :)
middle tier promotes code re-use, but it also promotes a _logical_ data schema over the _physical_ data schema which is exactly what putting logic in things like triggers and such in does not do.
Let's say you want to access the same group of tables from multiple places in your application, in different objects running on different hosts written by different people, and you don't have source to some of them. You've got 3 choices:
Option 1 is just silly - impossible to maintain for all but the most trivial cases. Option 2 adds an additional layer of indirection, hitting performance, it's another layer to test and another point of failure in production, and it's functionally the same as a trigger anyway. Or pick option 3, which has been refined over 2-3 decades in some of the toughest transactional processing apps in the world, keeps all you code in one place, and guarantees integrity even if you can't in your objects.
As an experienced system architect, one of the mistakes I see newbies make all the time is that they think because their tiers are logically distinct, they have to be physically distinct too. In a professional shop, your logical design will be done by a theoretician who doesn't even know or care what the eventual platform will look like, then the physical design is done by a hardcore, grey-haired DBA who's been there and done that on a dozen major projects. The programmers who actually implement it almost always don't see the big picture, because they're the specialists that focus on their own personal bits of the code.
> [schnip] and you don't have source to some of them.
if I don't have the source to applications that are accessing my database, then I'm in pretty big trouble. not having the source means I don't trust the app, and at that point it's like having a wide open door to your db. Sure you could play catch up with some triggers and such, but really, you're already in a bit of a mess aren't you?
Let's assume a reasonable environment though, we're you're building an app, and have control over the source. So - if twenty apps update 5 tables, then which sounds better - leave the database wide open and assume they can be updating it any which way, biting your nails worrying about a data integrity problem (like - maybe application a updates column a in one way and application b does it in another) or put the update code in one place, such that all applications go through the same api.
Preferably this api is a middle ware api, but it could just be an object to, middle ware is easier to maintain, but perhaps has more up front infrastructure.
As far as performance goes, that's just total bullshit. If anything, moving the core integrity checking off to another host, and freeing you're database server to do record management only will speed things up. Further, if reads and writes are funneled through a correct api you only need to change one set of code once when you want to change database schemas, which you _will_ want to do. Business requirements change, tables need to be added.
btw - in you're description of what 'professionals' do, how do the programers ever know of the logical data model if they are hitting the physical data directly?
there's a middle ground between all or no logic in the "storage layer"
You can still have a business logic layer. It's just that in many projects, that logic is faster and more efficient running as PL/SQL or TSQL than it is in some compiled DLL.
and one of the reasons that they'll "keep it around" is because they paid so damn much for it. why lock in an implementation decision for so long? it doesn't promote agility, nor does it promote flexibility. quite the opposite, it encourages poor SQL coding (i.e., vendor-specific features). it's called the "Golden Hammer" Anit-Pattern. look into it.
If you're talking about a serious piece of software (as opposed, to say, a web app for a shopping cart or something similarly as silly), flexibility isn't an issue. You simply don't go around switching databases for say, a bank or a credit card company or a health care provider. Any IT guy that says "let's switch databases" mid-stream for no good reason is incompetent. Projects that use things like Oracle generally use it because the company is stable, the projects are stable, and the project is going to live largely intact for many years.
um, no. gigabytes, maybe, but most companies have databases in the terabyte range? i don't think so.
It sounds like you're used to working on smaller, perhaps not misson-critial projects for smaller companies. Terrabyte+ databases are very common in most Fortune 500 companies, gov't institutions, etc. Who do you think keeps Sun in business? You don't buy Sun hardware for a 100 gig database. You get a PC.
Your assumption that flexibility is always so very important is wrong. No reasonable company is gonna be switching databases like they change their pencil suppliers. It just doesn't happen. Hell, I know of many instances where companies stay with the same *version* of database for 5+ years.
yeah, I don't like the dbdebunk stuff either. they spend too much time talking about how ignorant everyone is and too little time talking about real practical solutions.
If you're talking about a serious piece of software (as opposed, to say, a web app for a shopping cart or something similarly as silly), flexibility isn't an issue.
Flexibility is always an issue because requirements always change. To think and to code otherwise is folly and professional laziness. Anytime you get a set of requirements and code to them blindly without considering the ramifications on maintenance and future business objectives you invite disaster.
You simply don't go around switching databases for say, a bank or a credit card company or a health care provider.
Of course you cannot when they've been coded as you suggest. It's simply not practical, and maybe even not possible under your guidelines. If you code to SQL-92 whenever it can be done, switching databases becomes a real possibility.
Any IT guy that says "let's switch databases" mid-stream for no good reason is incompetent.
Straw man. Of course if there is "no good reason" it would indicate incompetence. However, there are often many good reasons to switch databases, such as constantly shifting licensing terms *cough*Oracle*cough*, ridiculous licensing fees *cough*Oracle*cough*, lack of standards *cough*Oracle*cough*, etc.
It sounds like you're used to working on smaller, perhaps not misson-critial projects for smaller companies. Terrabyte+ databases are very common in most Fortune 500 companies, gov't institutions, etc.
The original poster said "most companies", and "most companies" are not Fortune 500 or even Fortune 1000 companies. I thus stand by my statement that most companies do not have database systems in the terabyte range. And it sounds like instead of refuting my original points, you'd rather try to dismiss them by suggesting I don't have experience with mission critical systems. Fact is, the databases and applications I design, develop and deploy are carrier-class because they have to be.
Given your repeated mention of Oracle, it sounds like you're actually an Oracle developer as opposed to a SQL developer. That's okay, I suppose, as everyone needs to have a job.
Hell, I know of many instances where companies stay with the same *version* of database for 5+ years.
Uh-huh. And do the same companies have to maintain their code? How about extend it? Thought so.
You don't want to (unless, say, your organization grows rapidly and you need to migrate to a database and platform you couldn't previously afford), but what kind of leverage do you think you'll have with the vendor when it becomes known that you can't?
Sure, many databases have crummy optimization and need to be coddled with proprietary query syntax, but failing to bundle a tested ANSI-conforming equivalent is negligent.
A book that I found very helpful for learning SQL is Sams Teach Yourself SQL in 10 Minutes. When I first started learning SQL I mostly got everything from the early Slashcode sources and the MySQL manual as I needed it - not the best way to learn :-). I was a bit skeptical about the "10 minutes" approach, but each of the chapters actually did work out to about 10 minutes and the information was easy to understand (may have helped that I already knew some about SQL) and was fairly thorough. Another point that I really liked about it is that for the most part it only talked about the SQL standard, not just how one vendor implemented it. However, if an important vendor differed in their implementation, they would talk about it. This worked out great for me because I just wanted to know SQL basics and "best practices" and could figure out vendor specifics from their manuals.