About Maintaining a Database's Contents
In the Database Manager, you can view, change and delete
the tables, views and columns of a database. 
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The action of permitted viewing of a database is harmless, but direct editing and deletion of database components and contents are extremely risky. Such maintenance should only be done with advanced knowledge and due precautions.
You have to have the rights to perform the actions.
You should first make a back-up copy of the database, or part of a database, that is to be altered.
You must comply with other applications' requirements upon the databases. Specific warnings are included in the topics where such restrictions may apply.
Bear in mind that an otherwise valid change in one part of a database may cause inconsistency with the contents of other parts of that database.