Databases Reference
In-Depth Information
Gamma-quality interface and limited support
The Berkeley DB engine never became a fully integrated and supported part of
MySQL, and it could not be used on some non-Intel architectures. As mentioned
earlier, inbuilt support for the BDB engine was officially dropped from MySQL
version 5.1.12.
It's disk-hungry, like InnoDB
With the features that make it transaction safe and robust to recover comes the
cost of extra disk space for storing the information that's needed. MyISAM is much
more compact because it doesn't have those features.
It's difficult to set up
You generally need a compiler to generate the required program files from source
code. There are plenty of startup parameters and options, and you need to under-
stand and tune these to make effective use of the BDB engine. This is a good enough
reason not to use it, unless you really know what you're doing and why you want
it.
Exercises
Selected exercises in this section concern the
music
database. You'll find that the de-
scription of table structures in “The Music Database” in Chapter 4 is a useful reference:
1. Write a join query that displays the name of each artist and the albums they've
made. Alongside the album, display the number of tracks on the album.
2. Repeat Question 1, but now display only those albums that have more than 10
tracks.
3. Repeat Question 1, but write it as a nested query.
4. What are the four types of nested queries? For each type, write a sample query on
the
music
database. Try to use different keywords in each query, selecting from
ANY
,
ALL
,
EXISTS
(or
NOT EXISTS
), and
IN
(or
NOT IN
).
5. What is the difference between an
INNER JOIN
, a
LEFT JOIN
, and a
RIGHT JOIN
? Does
the order of tables matter in an
INNER JOIN
?
