# The consequence is that the algorithm for update be derivable at compile time.
 
# The consequence is that the algorithm for update be derivable at compile time.
 
#: (So could be implemented as a stored procedure.)
 
#: (So could be implemented as a stored procedure.)
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#: Suggested alternative formulation: “Whether a given view can be updated-through or not must be determined solely from the declared database constraints, the given view's definition, and the requested update to be performed to the view (and thus update through it).”
 
# ''Essential'' tuple means that it is ''necessary'' for those tuples to be deleted/inserted to comply with 1., 2 for all valid states of the database.
 
# ''Essential'' tuple means that it is ''necessary'' for those tuples to be deleted/inserted to comply with 1., 2 for all valid states of the database.
 
#: ''Essential'' attribute value means that value is the only possible to comply with 1., 2 for all valid states of the database.
 
#: ''Essential'' attribute value means that value is the only possible to comply with 1., 2 for all valid states of the database.
 
You could also target by content an update to doubly-linked list: insert before the leftmost cell value 'XYZ'; delete 3 cells to the right of the rightmost cell value 'ABC'.
 
You could also target by content an update to doubly-linked list: insert before the leftmost cell value 'XYZ'; delete 3 cells to the right of the rightmost cell value 'ABC'.
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The rewrites for updates given in this approach take that a target for update can be any relational expression, with a view name (virtual relvar) merely standing for its defining expression in a target context.
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The rewrites for updates given in this approach take it that a target for update can be any relational expression, with a view name (virtual relvar) merely standing for its defining expression in a target context.
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== Worked examples ==
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== [[Update through views: rewrites]] ==
   Exception encountered, of type "Error"