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<div class="moz-cite-prefix">Le 10/04/18 à 22:36, Wols Lists a
écrit :<br>
</div>
<blockquote type="cite" cite="mid:5ACD2037.9080908@youngman.org.uk">
<pre wrap="">On 10/04/18 16:55, Jean-Pierre Ledure wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Does this mean that once a .odb file containing an embedded HSQLDB
database is opened in LO 6.1 there is no way back ? That file cannot be
accessed anymore by a LO <= 6.0 user ? Is this acceptable ?
</pre>
</blockquote>
<pre wrap="">
It's normal to update the on-disk format, with the inevitable consequence
that old versions of the program cannot access newer versions of data.
</pre>
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When the database conversion is automatic without a fault back
scenario, then the software has at least to *GUARANTEE* that there
will be neither data loss nor functional loss afterwards.<br>
<br>
1. No data loss ?<br>
a) BOOLEAN datatypes are supported only since FB 3.0. Note that
LO 6.0 (I've not tested LO 6.1 yet) does not support boolean columns
with FB.<br>
b) VARCHAR datatypes are limited in size: with FB up to 32K, with
HSQLDB up to 2G. The workaround in FB is to use instead BLOB types
with TEXT subtype (default subtype = BIN). LO 6.0 does not support
subtypes.<br>
Shall those cases be solved in LO 6.1 ?<br>
<br>
2. No functional loss ?<br>
SQL Queries may be flagged as "direct SQL". It means that the RDBMS
will interprete the SQL command. FB and HSQLDB respective SQLs are
not 100% compatible. Will direct SQL sentences also be converted
automatically ?<br>
Whar about direct SQL sentences built thru a Basic expression ? They
are obviously not convertible.<br>
<br>
These are typîcal examples of compatibility risks. Probably there
are much more ...<br>
<br>
As a conclusion I call for a manual conversion triggered f.i. by a
*Save As ...* menu command (or a similar alternative). Additionally
the software modules for HSQLDB support should be kept.<br>
<br>
Thanks.<br>
Jean-Pierre<br>
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