On Wed, Sep 29, 2010 at 9:08 AM, LSA <[email protected]> wrote:
> Hi all!
>
> I need to perform quick search on dbf, i.e. find specific record by some
> attribute. I am thinking about using ODBC via JDBC, because
> 1) it can be used like this:
> Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
> String url = “jdbc:odbc:Driver={Microsoft dBase Driver
> (*.dbf)};DBQ=d:/shapefiles”;
> Connection con = DriverManager.getConnection(url);
> Statement st = con.createStatement(); ResultSet rs = st.executeQuery(“SELECT
> * FROM
> countries where name='Homeland' ”);
> st.executeUpdate(“CREATE TABLE NEWTABLE (NAME CHAR(32), PASSWD CHAR(32
> ))”); con.close(); 2) I don`t know, by I believe it can create index on
> specific field, so search will be about log2(n) time (n is recordCount).
>
That would be news to me. DBF does not define a standard attribute indexing
scheme. Maybe some drivers add custom indexes.
> 3) Default geotools data access is slow, unfortunately. Besides, it cannot
> use attribute index on dbf, as far as I know.
>
>
Not supported as far as I know.
> So, the question: Does anybody ever performed fast searches on DBFs?
> What did you used, if so?
>
> I'd suggest to load the data in to a fast embedded database such as H2 or
HSQL, if you have to do many repeated searches that will quickly pay off.
> If ODBC is a good choice? In future we will port our app to unixes, will we
> have dbf odbc there?
>
> Unlikely, but I may be wrong.
Cheers
Andrea
-----------------------------------------------------
Ing. Andrea Aime
Senior Software Engineer
GeoSolutions S.A.S.
Via Poggio alle Viti 1187
55054 Massarosa (LU)
Italy
phone: +39 0584962313
fax: +39 0584962313
http://www.geo-solutions.it
http://geo-solutions.blogspot.com/
http://www.linkedin.com/in/andreaaime
http://twitter.com/geowolf
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