Can i set some rules to a custom data tables ?

General
1

I would like to set a rules on the data table so that there is no duplication of data

2

Yes, you can, but uniqueness of data is determined at the column level:

    Select a table on the Data screen. Click "Table Schema and Permissions" Locate the column which must contain unique data Select "Unique Value" in the Constrains drop down. Click the pencil icon on the right side for column row.
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