CafeTran

 I don't think there exits an easy method to remove duplicate entries via the SQL command. But you can achieve it in CafeTran like this:

1. Recall all Total Recall segments to the working memory.

2. Remove duplicate units in the working memory via the Task menu.

3. Create a new TR table.

4. Send the working memory segments, now without duplicate units, to the new table.

5. Remove the old TR table.

Igor

The linked methods may work:

1. For that particular database vendor - each vendor has its own SQL flavor especially when it comes to th advanced SQL commands.

2. Only for simple tables with one column. When there are more than one column, the SQL command may get either extremely complex or impossible to achieve.

3. The current CT method is workable and it may be optimized in the future into one or two steps.

Igor

> Or perform such a command automatically after each import, that would be the Apple approach: don't bother users with thinks (tasks) that they don't need to now.

When there are millions of units in Total Recall, checking each imported unit for duplicates at import would take ages.

Igor

Perhaps in the cloud but I haven't test this solution. Total Recall is based on SQLite database. Please see here:

http://www.sqlite.org/whentouse.html

It is possible to implement it on other types of databases which are appropriate for the network access. Maybe sometime in 2016, I will add the Total Recall implementation based on MySQL or Oracle databases.  

Igor