Hi I think a trigger is the most database independent solution.
About CHECKSUM TABLE: the MySQL docs say that "the fact that two tables produce the same checksum does not mean that the tables are identical." H2 internally keeps a modification counter for each table, I will make it available in the next release: New meta data column INFORMATION_SCHEMA.TABLES.LAST_MODIFICATION to get the table modification counter. Example: DROP TABLE IF EXISTS TEST; CREATE TABLE TEST(ID INT PRIMARY KEY, NAME VARCHAR(255)); INSERT INTO TEST VALUES(1, 'Hello'); select last_modification from information_schema.tables t where t.table_name = 'TEST'; INSERT INTO TEST VALUES(2, 'World'); select last_modification from information_schema.tables t where t.table_name = 'TEST'; SELECT * FROM TEST ORDER BY ID; select last_modification from information_schema.tables t where t.table_name = 'TEST'; UPDATE TEST SET NAME='Hi' WHERE ID=1; select last_modification from information_schema.tables t where t.table_name = 'TEST'; DELETE FROM TEST WHERE ID=2; select last_modification from information_schema.tables t where t.table_name = 'TEST'; Regards, Thomas On Tue, Dec 2, 2008 at 10:33 PM, Daniel Pont <[EMAIL PROTECTED]> wrote: > > Why not a trigger ? > > See http://www.h2database.com/html/features.html#triggers > > On 2 déc, 16:58, Lennart Schedin <[EMAIL PROTECTED]> wrote: >> I have the following problem: >> >> I have a large table (typically 20 Mb of data). I have one Java >> program that needs the data but only for reading. The Java program >> contains a thread that periodically reads the entire table into main >> memory (about 1 read per minute). >> >> This causes a lot of network traffic (since I have several Java >> programs). >> >> Is there any way to determine if a table has changed since my last >> read? In Mysql for example there is a CHECKSUM TABLE feature that can >> be used to only transfer the checksum of the table. That way I can in >> my Java program determine if I must read the entire table or not. > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "H2 Database" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/h2-database?hl=en -~----------~----~----~----~------~----~------~--~---
