On 13 Aug 2015, at 5:55am, Chris Parsonson <z2668856 at gmail.com> wrote:
> The tables are very simple. They have a primary key, but no relationship > between tables in the sense that you mean. Synchronisation will be add new > rows, and update some rows, no deletions To access two different databases with one database connection, use the ATTACH command. Method 1 -------- To find rows which are in one table but not in the other, use EXCEPT SELECT primaryKeyColumn FROM databasea.myTable EXCEPT SELECT primaryKeyColumn FROM myTable In cases where a row has been updated with a new value in one column, how do you propose to decide which value is the 'right' one to put in both databases ? Method 2 -------- Ignore Method 1. In each copy of your database keep a log of all INSERT and UPDATE commands executed since the last 'synchronize': CREATE TABLE commandsSinceLastSynch (theCommand TEXT) To synchronise the two copies, play back the log for copy A to copy B and the log for copy B to copy A. Simon.
