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Relational Algebra

Posted on 2004-10-10
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Last Modified: 2008-02-26
Is there a way I can test relational algebra operations online?  If so, what is the website.  Can I use relational algebra in MySQL or MS Access?

I'd like to verify my operations will yield what I think they will yield.

Thanks.
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Question by:jello32
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6 Comments
 
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Expert Comment

by:jdlambert1
ID: 12272073
You can do it in any environment that allows you to create and manipulate variables, which means programming, more than databases, though you can certainly use data in a database in your operations.

Access allows you to program in VBA -- Visual Basic for Applications.
MySQL doesn't provide for stored procedures (programming commands added to SQL) in the released version, but it will be available in version 5, which can already be downloaded in a beta test.
SQL Server and Sybase use Transact-SQL (T-SQL) in stored procedures.
Oracle uses PL/SQL in stored procedures.
DB2 uses IBM-SQL in stored procedures.
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Author Comment

by:jello32
ID: 12272106
if I program it, then it's not exactly the operations.

For example if I have the following relational tables:
PERSON(Name, Hometown)
GROWS(Hometown, Flower)
ALLERGIES(Name, Flower)

and I want to do

PERSON / ALLEGIES

where / is division, then I'd have to program what division does. Is that right? So that would be subject to logic errors.  I was wondering if I can input the relations, select the table names and operations and see the results.
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Accepted Solution

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vorb1s earned 50 total points
ID: 12276040
If you want to know more about relational Algebra, try this web: http://db.grussell.org/section010.html
There is also something for online testing under link: Online SQL
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LVL 15

Expert Comment

by:jdlambert1
ID: 12276421
You can't do mathmatical operations between tables, but you can between columns, if the columns are numeric data types. E.g., if Price and Tax are decimal values, then you can put (Price * Tax) or (Price/Tax) in your SELECT statement.
 
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Author Comment

by:jello32
ID: 12281034
jdlambert1 division is a relational algebra operation.

vorb1s - thanks. that site has a says in the future they'll put up online testing for relational algebra.  It's sorely needed.
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LVL 15

Expert Comment

by:jdlambert1
ID: 12281369
>division is a relational algebra operation
Yes, that's why I gave an example of dividing one column's values by another column's values.
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