Database Management
Reference Manual
Introduction to Database Concepts
:
Data Access Control (DACs)
: Attribute Modification
Attribute Modification
The following checks are applied when modifying attributes:
1.
the attribute value is the right type
2.
the attribute is valid for the given element
Modify Related Attributes
Sometimes modifying one attribute will actually cause a number of attributes to change. There are two main cases where this might happen:
1.
There is a dynamic rule on another element dependent on this element (see section Rules for description of rules)
2.
There is built in code that keeps a number of attributes synchronised. This is used for some Draft attributes and some cross references.
Change Cross Referenced Attributes
The integrity of cross referenced attributes is maintained when one end of the connection is changed. Changing one end of a connection will also change the following:
1.
If there is an existing connection, the corresponding attribute on the element at the other end of the existing connection, is unset.
2.
For the new element connected, if this is already connected, then this connection is unset, which itself may change the element at the other end.
In essence, changing one value may result in four elements being updated.
For example, consider the following:
After setting the CREF on /N1 to /B1, the end result is:
1974 to current year.
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