[mdb-dev] mdbtools-java: thanks!, status?, bug reports

[Caleb D. <dr...@cs...>]

First of thanks to whomever did the Java port, I believe it was Calvin 
Smith.  I need to read data from an mdb file on a Linux system via a 
Java servlet, and this project (almost) allowed me to do that.  I first 
used the libmdb package ala mdb_export, but I found the test code that 
does DriverManager.getConnection("jdbc:mdbtools:" + filename), which 
worked well.  Even though very little of the java.sql interfaces are 
implemented, we have Statement.executeQuery and ResultSet.getString, 
which are sufficient for my purposes.  Thanks again!

Other posts indicate that the Java port is a bit out-of-date, so perhaps 
the memo bug I describe below has been fixed in the C version.  From the 
libmdb code, it looks like some manual intervention is required to turn 
the C into Java, so perhaps this is why.

I am not part of the mdbtools team and have not participated in any such 
project, so I will describe two bugs I found and apologize for not 
fixing them.

1) Java bug (crucial, but trivial): in DataResultSet.getString(String), 
the method loops through the column names to get the index to call 
DataResultSet.getString(int), which does the real work.  
DataResultSet.getString(int) correctly accounts for the fact that 
ResultSet.getXXX(int) method number the columns from 1, as does SQL.  
However, DataResultSet.getString(String) does not account for the 
offset.  Line 168 "return getString(i);" in the for loop should be 
return "getString(i + 1);".  (I'm not sure what the plans are for the 
Java wrappers, but obviously a table from column names to indices in 
DataResultSet would be better.)

2) I'm getting various index out of bounds errors from 
mdbtools.libmdb.Data.mdb_memo_to_string that are preventing me from 
reading tables that have a column of type "memo".  I can't even query 
the other columns because the current implementation reads the entire 
tale into memory, no matter what columns are in the query (right?).  I'm 
getting negative values for the string length and a value > 4096 for 
row_start, which is used as an index into MdbHandle.page_buf.