Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Most of the (earlier) answers here are a reflection of the fact that most people do not know what SQL is (its an implementation of Relational Calculus) or what that means (that it's a form of Predicate Logic). The following statements are true of both Prolog and SQL:</p> <ul> <li>they are both logic-driven</li> <li>they can both store, express and use relations (logical relationships in Prolog)</li> <li>they can both store and express complex logical conditions</li> <li>they both have facts(data in SQL) and can derive conclusions from those facts</li> <li>they both have queries, that do in fact mean the same thing</li> <li>they both have data(facts in Prolog) and use them similarly</li> <li>they are both programming languages</li> <li>they are both turing-complete (though it is somewhat difficult to access this in both of them)</li> <li>etc, etc..</li> </ul> <p>Generally, people are not aware of these equivalences between them:</p> <ol> <li>"Facts" and "Data" are the same thing. This is straight out of Codd's original paper.</li> <li>A "Relation" in Relational Theory is the same thing as a "Table" in SQL, is the same thing as a Relation or relational function in Predicate Logic and is the same thing as a tuple-set in Set Theory</li> <li>An aliased table-expression (i.e., a View, etc.) in SQL is the same thing as a Rule in Prolog.</li> </ol> <p>So what are their differences? Although they operate across the same conceptual domains, their focuses are in completely different directions. In Prolog terms, SQL is primarily a Fact and Relation(set) engine, whereas Prolog is primarily a Rules and Inferencing engine. Each can do the other, to a limited extent, but it becomes increasingly difficult with even small increases in complexity. For instance, you can do inferencing in SQL, but it is almost entirely manual in nature and not at all like the automatic forward-inferencing of Prolog. And yes, you can store data(facts) in Prolog, but it is not at all designed for the "storage, retrieval, projection and reduction of Trillions of rows with thousands of simultaneous users" that SQL is.</p> <p>Plus, SQL is primarily a Server-language paradigm, whereas Prolog is primarily a Client-language paradigm.</p>
    singulars
    1. This table or related slice is empty.
    1. POComparing SQL and Prolog
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USRBarryYoung
    1. USRBarryYoung
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POComparing SQL and Prolog
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTDownMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COhmm.. while your last paragraph makes sense to me (says basically what I said) the points list does not. As far as I can tell all of those points can be said about any (general purpose) programming language. What makes them different and useful is their "focus".
      singulars
      1. PO
      1. USHogan
    2. CO+1. Worth a mention Datalog as the "missing link" between Prolog and Relational Calculi (and then SQL).
      singulars
      1. PO
      1. USMaD70
    3. COFor a practical application of such "convertibility" see my answer to "Prolog to SQL converter" (http://stackoverflow.com/questions/724377/prolog-to-sql-converter/1682486#1682486) where I list some programs for such conversion.
      singulars
      1. PO
      1. USMaD70
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload