I have a table that contain several columns, each has their own data. then, someone have made some change in the data (just a little one data editing). how do i know later what data have been edited/changed using MapInfo SQL Query? thanks.
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You would have to refer to a backed up version of the table. Assuming you have a backup then if you loaded the backup and current version of the table you could do something like select * from <currenttable>,<backuptable> where <currenttable>.<uniquekey> = <backuptable>.<uniquekey> and <currenttable>.<col1> <> <backuptable>.<col1> into selection. Once you've got the syntax down you could create a MBX file to iterate through the columns. Other than that MapInfo doesn't do versioning in the same way that ArcSDE does for example.– MarkSep 3, 2013 at 10:59
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Mark, you should write this as an answer– Peter Horsbøll MøllerSep 3, 2013 at 11:26
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If you happen to have your table connected to a database, you could let the database handle the versioning. Have a trigger create copies of the records when they get changed– Peter Horsbøll MøllerSep 3, 2013 at 11:28
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Sir, what do you mean by "<currenttable>.<col1> <> <backuptable>.<col1>"?– hairuSep 4, 2013 at 2:26
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@hairu this is a comparison between the contents of col1 in the backed up version of the data against the same column in the current version of the data - the <> equates to "not equal to". So if the table was named myDataset, ID was a primary key and the first column that you're interested in is address you're query may look like "Select * from myDataset, myDataSet_backup where myDataSet.ID=myDataSet_backup.ID and myDataSet.Address <> myDataSet_backup.Address into selection". The selection would then contain records where the feature is the same between the 2 tables and address has changed– MarkSep 4, 2013 at 7:00
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You would have to refer to a backed up version of the table. Assuming you have a backup then if you loaded the backup and current version of the table you could do something like
select * from <currenttable>,<backuptable> where <currenttable>.<uniquekey> = <backuptable>.<uniquekey> and <currenttable>.<col1> <> <backuptable>.<col1> into selection
Once you've got the syntax down you could create a MBX file to iterate through the columns. Other than that MapInfo doesn't do versioning in the same way that ArcSDE does for example.
