Hi,

First of all a BIIIG thank you to Helen for writing this
outstanding book. At last I'm having a complete picture of
the intimate workings of the Firebird RDBMS. Page after page
of most useful information, especailly for a newbie to FB
and RDBMS like me.

While reading the book I wrote down underneath questions for
which I'd appreciate some clarification or advice.

Development configuration:
- Firebird Embedded 1.5.1.4481
- Windows 98 SE ( Build 4.10.2222 A )
- Delphi 7.0 Professional US ( Build 8.1 )

Usage configuration:
- Windows 95, 98, ME, XP, 2000

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1. pg 181 - footnote: "BLOB storage is not a magic bullet
for storing and retrieving large volumes of huge binary file
data. Sometimes, under production conditions, the overhead
and unwieldiness of storing non-dynamic data objetcs like
movies or sound recordings inside the database overwhelm the
benefits you perceived in the lab. Storing filesystem links
to objects can be a valid approach."

Q1.1: What do you mean by 'the overhead and unwieldiness ...
overwhelm the benefits you percieved in the lab' ?

Q1.2: Where can I find practical information about setting
up a 'storing filesystem links to objects' approach ?

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2. pg 246 - Read-Only databases: "The application will have
to be written so as to avoid requests that involve writing
to the database or to trap the exceptions reaised when they
are attempted."

Q2.1: What's the best way to organize this: two separate
applications one to read-write the database and another one
to read it or can both options be implemented in one
application ? Example(s) ?

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3. pg 247 - Making a database Read-Only: "Either gfix or gbak
can be used."

Q3.1: What does using gfix or gbak precisely do to the
database in the process of making it read-only ?

Q3.2: Is there anything else to modify manually/through scripting
to the database itself after the gfix/gbak operation ?

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4. pg 445 - Configuring Transactions, Access Mode: "Access
mode can be read-write or read-only."

Q4: Do transactions have to be changed to read-only access
mode to use a database as a read-only database ?

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5. pg 597 - TIP: "Although FB does not provide a debugging
feature for SPs, several 3rd party tools provide this
capability."

Q5: Which tools ?

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6. pg 656 - The Lookup Table: "A lookup or control table is
typically a static table with a small row count, which may
be used in a similar way in several contexts. It consists of
a small primary key and a description field, calculation
factor, or some rule that processes need to refer to. ...
Because one row in a lookup table supplies information to
many rows, a slavish adherence to relational analysis rules
often results in FK being bestowed on the lookup key columns
of the user tables."

Q6: Is there some rule of thumb/calculation rule to make
up whether a table is to be considered as a lookup table or
not. A threshold value of the index selectivity ?

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7. pg 694 - Windows Embedded Server: "The internal security
of a database designed for embedded server use has to be
protected with SQL permission that limit access to a
specific user name. That in itself is a can of worms on a
stand-alone machine that is physically available to passers-
by."

Q7: Is this also true when running the embedded server on
a PC which doesn't run a full server ? If so, please explain
why it is 'a can of worms' and which beast is most suited to
eradicate the worms.

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Thanks a lot,
Alain