I have a question regarding the efficiency of an explicit JOIN statement vs.
an implicit one.
What I mean:
I have a many-to-many mapping through a mapping table. I.e. I have different
types of tools mapped to several categories in which they might belong. For
instance, a complete programming suite may be categorized both as a
debugger, a C-compiler and an assembler... This programming tool is mapped
to all these 3 categories through a table just coupling the id's against
each other...
If the ID of the programming tool itself is 134, the entries for this tool
in the mapping table will be like this:
+--------+--------+
| ToolID | TypeID |
+--------+--------+
| 134 | 24 |
| 134 | 19 |
| 134 | 17 |
+--------+--------+
Now I wonder, when extracting all the info for a certain tool from the
database, will it actually be more efficient to use the explicit JOIN
statement rather than just tie the keys to one another in the query?
This may seem very basic to some; but my formal database knowledge IS very
basic. Please, if you can shed some light on the topic or give me som
epointers to a good reference; you are very welcome to do so!
Best regards,
Eivind :-)
<sql, query>
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