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Free
Database Design for Mere Mortals : A Hands-On Guide to Relational Database Design
Relational Database Design for Mere Mortals explains the concepts of relational-database design in an easy-to-digest fashion that covers both the theoretical underpinnings and their practical implications. Hernandez covers all the basics--table and field structure, keys, relationships, business rules, and more--but always keeps his feet on the ground with advice for real-world implementations and a particularly strong section on analyzing your current database infrastructure. Designing
Relational Database Systems |
Free Relational Database Tutorial and Tips For Beginners!Intro To Data ModelingLesson 2 First, the relational concept says break up the single file into three files. Each one will be dedicated to serving one of the three types of information that that the single file was trying to handle. One type of info was keeping track of who the patrons are, so a whole file is dedicated only to patron info. Looks like this: PATRON FILE
The other general type of info was the book info. It looks like this: BOOK FILE
Finally, we have a cool concept that handles the fact that a patron checked out a book. We create a third file that contains just enough info to identify a patron, the book that was checked out, and when. This clever file looks like this: INTERSECTION FILE
Its called an intersection file because its kind of an intersection between the patron file and the book file Notice that you've only had to type in Andrew's address once (in the patron file), and now that he's ready to check out books, you use the intersection file, where you only have to type in his name, the book title and when it was checked out. You don't have to type in Andrew's address over and over again! Hooray! Hmmm...interesting you say, but so far all I've done was create 3 files. What kind of weirdo system is this? The information is more scattered around than before! Don't worry! There's software that does all the rest for you! Software like dBase, Oracle, Microsoft Access, FoxPro, etc. The software ties together all of the information from all three files and displays it so that its logically connected. Here's what it does: first, it matches all the patron names from the intersection file with the patron names from the patron file and brings the patron and intersection info together. So far, the software is starting to collect the data from the patron and intersection files like this:
The software saw that "Andrew" was in the intersection file and that "Andrew" was in the patron file, so it took all the matching data from both files relating to "Andrew" and brought it together as shown in the table above. But its not done yet. Then the software gets the book names from the intersection file and matches that with the book names from the book file and adds the author info from there to the information already collected in the table above. Then, the info looks like this: (Below is a computer screen display of what you would see)
The software saw that "Tennis!" was in the intersection file and that "Tennis!" was in the book file, so it took all the data from both files relating to "Tennis" and brought it together. So now, the software has done all the work matching the info from the three files and it displays the results for you in a logical manner. It then repeats all of the above for Andrew's other checked out book and Martina's checked out book. Okay, you say, but, isn't it a hassle to keep 3 files open like that at the same time to enter the data? Click here to continue Data Modeling Essentials : Analysis, Design, and Innovation 
An innovative "how-to" guide and design aid to data modeling. This book
discusses the theory and practice of data modeling as a design activity,
and shows the reader how to increase quality and stimulate creativity with
new modeling approaches. The book is useful as both a basic learning tool,
and a thought provoking guide to higher achievement in designing and executing
data models.
Data Modeling for Information Professionals 
Explains to members of a project team creating an information system, especially
a computerized system, how to structure data. Discusses such aspects as
what data models are, what makes them successful and fail, the components
of an enterprise data model, domains, predicates, entities, classes, relationships,
and attributes. The CD-ROM contains two full-function CASE repositories
developed during the redesign of a travel tour company.
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