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Annotation of 43BSD/ingres/doc/quel/integrity.nr, revision 1.1.1.1

1.1       root        1: .th INTEGRITY QUEL 2/7/79
                      2: .sh NAME
                      3: integrity \- define integrity constraints
                      4: .sh SYNOPSIS
                      5: .bd "define integrity on" 
                      6: var 
                      7: .bd is 
                      8: qual
                      9: .sh DESCRIPTION
                     10: The 
                     11: .it integrity 
                     12: statement adds an integrity constraint for the
                     13: relation  specified by 
                     14: .it var.
                     15: After the constraint is placed,
                     16: all updates to the relation must satisfy 
                     17: .it qual.
                     18: .it Qual 
                     19: must be
                     20: true when the 
                     21: .it integrity 
                     22: statement is issued or else a diagnostic is issued 
                     23: and the statement is rejected.
                     24: .s3
                     25: In the current implementation, 
                     26: .it integrity 
                     27: constraints are not
                     28: flagged  \-  bad  updates  are simply (and silently) not performed.
                     29: .s3
                     30: .it Qual 
                     31: must be a single variable  qualification  and  may  not
                     32: contain any aggregates.
                     33: .s1
                     34: .s3
                     35: .it integrity 
                     36: statement may be issued only by  the  relation
                     37: owner.
                     38: .sh EXAMPLE
                     39: /\*(** Ensure all employees have positive salaries \*(**/
                     40:   range of e is employee
                     41:   define integrity on e is e.salary > 0
                     42: .sh "SEE ALSO"
                     43: destroy(quel)

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