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Constraint name
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Name of the referential integrity constraint. Maximum length is 254 characters
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Implementation
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Specifies how referential integrity will be implemented. You can choose between:
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Declarative- Referential integrity constraints are defined for particular references. When the reference is generated the target DBMS evaluates the reference validity and generates appropriate error messages
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Trigger - Referential integrity constraints are implemented by triggers based on the integrity constraints defined in the reference property sheet. The trigger evaluates reference validity and generates appropriate user-defined error messages
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Cardinality
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Indicates the minimum and maximum number of instances in a child table permitted for each corresponding instance in the parent table. The following values are available by default:
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0..* - A parent can have zero or more children. There is no maximum.
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0..1 - A parent can have zero or one children.
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1..* - A parent can have one or more children. There is no maximum.
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1..1 – A parent must have exactly one child
Alternately, you can enter your own integer values in one of the following formats:
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x..y - A parent can have between x and y children.
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x - A parent can have exactly x children.
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x..y, a..b - A parent can have between x and y or between a and b children.
You can use * or n to represent no limit.
Examples:
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2..n – There must be at least 2 children.
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10 - There must be exactly 10 children.
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1..2, 4..n – There must be one, two, four or more children.
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User-defined
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Indicates a user-defined constraint name
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Update constraint
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How updating a key value, in the parent table affects the foreign key value in the child table. Depending on the implementation and DBMS, you can choose between:
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None - Update or deletion of a value in the parent table has no effect on the child table.
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Restrict - A value in the parent table cannot be updated or deleted if one or more matching child values exists
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Cascade - Update or deletion of a value in the parent table causes an update or delete of matching values in the child table
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Set null - Update or deletion of a value in the parent table sets matching values in the child table to NULL
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Set default - Update or deletion of a value in the parent table sets matching values in the child table to the default value
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Delete constraint
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How deleting a row in the parent table affects the child table
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Mandatory parent
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Each foreign key value in the child table must have a corresponding key value, in the parent table
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Change parent allowed
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A foreign key value can change to select another value in the referenced key in the parent table
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Check on commit
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[SQL Anywhere® 5.0 and 5.5 only] Verifies referential integrity only on the commit, instead of verifying it after row insertion. You can use this feature to control circular dependencies
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Cluster
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Indicates whether the reference constraint is a clustered constraint (for those DBMSs that support clustered indexes)
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