Guardian Procedure Calls Reference Manual

nf-alt-files
is a one-byte value that specifies the number of alternate-key files for this primary file.
nk-alt-keys
isa one-byte value that specifies the number of alternate-key fields in this primary file.
Key Description
The key description for key k consists of four words, each of the form:
80
key-specifier[k * 4 + 1]
key-attributes[k * 4 + 2]
key-lennull-value[k * 4 + 3]
key-filenum[k * 4 + 4]
where:
key-specifier
is a two-byte value that uniquely identifies this alternate-key field. It must be nonzero.
This value is passed to the KEYPOSITION procedure for references to this key field.
key-attributes
describes the key:
Means that a null value is specified. See null-value below1<0>
Means that the key is unique. If an attempt is made to insert a record that duplicates
an existing value in this field, the insertion is rejected with a “duplicate record”
error.
1<1>
Means that Enscribe cannot perform automatic updating of this key.1<2>
Means that alternate key records with duplicate key values are ordered by the
value of the primary record key field. This attribute has meaning only for alternate
keys that allow duplicates.
0<3>
Means that alternate key records with duplicate key values are ordered by the
sequence in which those records were inserted into the alternate-key file. This
attribute is allowed only for alternate keys that allow duplicates.
1
Specifies the number of bytes from the beginning of the record to where this key
field starts. The maximum key offset is equal to the maximum record length minus
1 and depends on the file organization and format.
<4:15>key-offset
null-value
is a one-byte value, used to specify a null value if key-attributes.<0> is equal to
1.
During a write operation, if a null value is specified for an alternate-key field and if the
null value is encountered in all bytes of this key field, the file system does not enter the
reference to the record in the alternate-key file. (If the file is read using this alternate-key
field, records containing a null value in this field will not be found.)
During a WRITEUPDATE operation (write-count = 0), if a null value is specified
and if the null value is encountered in all bytes of this key field within buffer, the file
system deletes the record from the primary file but does not delete the reference to the
record in the alternate file.
232 Guardian Procedure Calls (C)