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HP COBOL
Reference Manual
Format 2 (Alpha, I64)
- The SORT statement sorts the table referenced by
table-name and presents the sorted table in
table-name either in the order determined by the ASCENDING or
DESCENDING phrases, if specified, or in the order determined by the KEY
phrase associated with table_name.
- To determine the relative order in which the table elements are
stored after sorting, the contents of corresponding key data items are
compared according to the rules for comparison of operands in a
relation condition, starting with the most significant key data item.
- If the contents of the corresponding key data items are not equal
and the key is associated with the ASCENDING phrase, the table element
containing the key data item with the lower value has the lower
occurrence number.
- If the contents of the corresponding key data items are not equal
and the key is associated with the DESCENDING phrase, the table element
containing the key data item with the higher value has the lower
occurrence number. <>
Additional References
Examples (Alpha, I64)
The following examples all illustrate the use of table sorting (Format
2). For examples on Format 1 sorting, refer to the HP COBOL User Manual.
The first example is a simple sort in which the table is sorted by the
key definitions in the OCCURS clause of data item tabl.
elem-item2 is the major key (ascending) and
elem-item1 is the secondary key (descending). A SEARCH ALL
statement is used.
identification division.
program-id. EXAMPLE1.
data division.
working-storage section.
01 group-item.
05 tabl occurs 10 times
ascending elem-item2
descending elem-item1
indexed by ind.
10 elem-item1 pic x.
10 elem-item2 pic x.
procedure division.
1. display "Example 1".
move "13n3m3p3o3x1x1x1x1x1" to group-item.
sort tabl.
search all tabl
at end
display "not found"
when elem-item1 (ind) = "m"
if (elem-item1 (ind - 1) = "n")
and (elem-item1 (ind + 1) = "1")
display "elem-item1 is descending order - 2nd key"
else
display "sort failed"
end-if
end-search.
exit program.
end program EXAMPLE1.
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The following example is also a simple sort in which the table is
sorted by the key definitions in the OCCURS clause of data item
tabl. elem-item2 is the major key (ascending) and
elem-item1 is the secondary key (descending). A SEARCH ALL
statement is used.
identification division.
program-id. EXAMPLE2.
data division.
working-storage section.
01 group-item.
05 tabl occurs 10 times.
10 elem-item1 pic x.
10 elem-item2 pic x.
procedure division.
2. display "Example 2".
move "13n3m3p3o3x1x1x1x1x1" to group-item.
sort tabl ascending.
if tabl (1) = "13"
and tabl (2) = "m3"
display "tabl is ascending order"
else
display "sort failed"
end-if.
exit program.
end program EXAMPLE2.
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This following example is a simple sort in which the table is sorted in
ascend- ing order using each entire element of the table (data item
tabl) to determine the sequence.
identification division.
program-id. EXAMPLE3.
data division.
working-storage section.
01 group-item.
05 tabl occurs 10 times
ascending elem-item3
descending elem-item1.
10 elem-item1 pic x.
10 elem-item2 pic x.
10 elem-item3 pic x.
procedure division.
3. display "Example 3".
move "13bn3cm3ap3do3fx1ex1ix1hx1gx1a" to group-item.
sort tabl descending elem-item2 elem-item3.
if tabl (1) = "o3f"
and tabl (2) = "p3d"
display "tabl is descending order"
else
display "sort failed"
end-if.
exit program.
end program EXAMPLE3.
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The following example sorts only the third instance of tabl2,
that is, tabl1(3). The qualified data item,
elem-item1 of group2 is its key. In normal PROCEDURE
DIVISION reference, elem-item1 of group2 requires two
levels of subscripting/indexing, whereas here it has none. Similarly,
tabl2 normally requires one level of subscripting, but cannot
be subscripted as data-name2 in the SORT statement. Instead it
uses the value of t1-ind for determining which instance is
sorted.
identification division.
program-id. EXAMPLE4.
data division.
working-storage section.
01 group-item.
05 tabl1 occurs 3 times
indexed by t1-ind t2-ind.
10 tabl2 occurs 5 times.
15 group1.
20 elem-item1 pic x.
15 group2.
20 elem-item1 pic 9.
procedure division.
4. display "Example 4".
move "x5z4y6z6x4a3b2b1a2c1j7j8k8l7j9" to group-item.
set t1-ind to 3.
sort tabl2 descending elem-item1 of group2.
if group1 (3 1) = "j"
and group2 (3 1) = "9"
and tabl1 (1) = "x5z4y6z6x4"
and tabl1 (2) = "a3b2b1a2c1"
display "tabl1 (3) is descending order"
else
display "sort failed"
end-if.
exit program.
end program EXAMPLE4. <>
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6.8.34 START
Function
The START statement establishes the logical position of the File
Position Indicator in an indexed or relative file. The logical position
affects subsequent sequential record retrieval.
file-name
is the name of an indexed or relative file with sequential or dynamic
access. It cannot be the name of a sort or merge file.
key-data
is one of the following:
- The data-name specified as a record key
- The segmented-key name specified as a record key
- The leftmost part of a record key
- The relative key for file-name
It can be qualified.
stment
is an imperative statement executed for an invalid key condition.
stment2
is an imperative statement executed for a not invalid key condition.
Syntax Rules
- To use the REGARDLESS or ALLOWING options, the program must include
these entries:
- APPLY LOCK-HOLDING clause of the I-O-CONTROL paragraph
- ALLOWING option of the OPEN statement
- There must be an INVALID KEY phrase if file-name does not
have an applicable USE AFTER EXCEPTION procedure.
- For a relative file, key-data must be the file's RELATIVE
KEY data item.
- For an indexed file, key-data can be either:
- A record key for the file.
- A data item subordinate to the description of a record key for the
file. The data item must have the same leftmost character position as
the record key, and must be one of the following:
- A group, alphanumeric, or alphabetic item
- An unsigned numeric display item
- A COMP-3 integer or a COMP integer
All the data types in the preceding list except alphanumeric are
Hewlett-Packard extensions.
- The REGARDLESS and ALLOWING options are Hewlett-Packard standard
syntax, and cannot be used for a file connector that has had (on Alpha
and I64) X/Open standard syntax (WITH [NO] LOCK or LOCK MODE) specified.
General Rules
All Files
- The file must be open in the INPUT or I-O mode when the START
statement executes.
- If there is no KEY phrase, the implied relational operator is EQUAL.
- START statement execution does not change: (a) the contents of the
record area or (b) the contents of the data item referred to in the
DEPENDING ON phrase of the file's RECORD clause.
- The comparison specified by the KEY phrase relational operator
occurs between a key for a record in the file and a data item. If the
file is indexed, and the operand sizes are unequal, the comparison
operates as if the longer one was truncated on the right to the size of
the shorter.
- START LESS can only be used with a file whose organization is
INDEXED and whose access mode is DYNAMIC. The file must be opened for
INPUT or I-O.
- For indexed files, the file system compares the Key of Reference
according to the native collating sequence and the sort order of the
Key of Reference. The comparisons IS GREATER THAN, IS GREATER THAN OR
EQUAL TO, and IS NOT LESS THAN refer to the logical record order,
according to the sort order of the key. For example, if the sort order
is descending, the KEY GREATER THAN key-data phrase positions
the file at the next record whose key is less than key-data.
All other numeric or nonnumeric comparison rules apply.
The
File Position Indicator is set to the first logical record in the file
whose key satisfies the comparison.
If no record in the file
satisfies the comparison:
- The invalid key condition exists.
- START statement execution is unsuccessful.
- The File Position Indicator denotes that no valid next record is
established.
- On Alpha and I64 systems, START LESS, LESS OR EQUAL, and NOT
GREATER set the file position indicator by making reference to the
logical record order in the same manner as START GREATER, GREATER OR
EQUAL and NOT LESS. <>
- The START verb can use the KEY IS syntax to establish the key
field within the file record which is the Key of Reference. An
immediately subsequent READ PRIOR will follow the order of the Key of
Reference to access the logically previous record in the file according
to that Key of Reference. If the KEY IS syntax is not used, the Key of
Reference is understood to be the file's primary key field.
- On Alpha and I64 systems, when a successful START LESS, LESS OR
EQUAL or NOT GREATER has occurred and the Key of Reference has
ascending order, the record pointed to by the file position indicator
can have the same key value or a smaller key value than the preceding
record for the Key of Reference. If the Key of Reference has descending
order, the record pointed to can have the same key value or a higher
key value for the Key of Reference. The record pointed to can have the
same key value if duplicate values for the Key of Reference exist on
the file.
- On Alpha and I64 systems, when an unsuccessful START LESS, LESS OR
EQUAL or NOT GREATER has occurred the key of reference is undefined and
a File Status value of 23 is returned, which indicates the INVALID KEY
condition, or record not found. <>
- The START statement updates the FILE STATUS data item for the file.
- If the File Position Indicator denotes that an optional file is not
present when the START statement executes, the invalid key condition
exists. START statement execution is then unsuccessful.
- The REGARDLESS and ALLOWING options can be used only in a manual
record-locking environment. To create a manual record-locking
environment, an access stream must specify the APPLY LOCK-HOLDING
clause of the I-O-CONTROL paragraph.
- The REGARDLESS option allows an access stream to position to a
record regardless of any record locks held by other concurrent access
streams. The START REGARDLESS option holds no lock on the record
positioned to.
This statement generates a soft record lock
condition if the record that is pointed to is locked by another access
stream. This condition results in a File Status value of 90 and invokes
an applicable USE procedure, if any. Execution of the START REGARDLESS
statement is considered successful and execution resumes at the next
statement following the START REGARDLESS statement.
However, on
Tru64 UNIX systems, the soft lock condition (file status 90) is not
recognized for indexed files. A START REGARDLESS statement for a record
locked by another process performs the requested operation on the
record and returns a file status of 00. <>
- On OpenVMS, the ALLOWING UPDATERS option permits other concurrent
access streams in the manual record-locking environment to
simultaneously READ, DELETE, START, and REWRITE the current record.
This option holds no lock on the current record.
- The ALLOWING READERS option permits other concurrent access streams
in the manual record-locking environment to simultaneously READ the
current record. This option holds a read-lock on each such record read.
No access stream can update the current record until it is
unlocked.<>
- On OpenVMS, the ALLOWING NO OTHERS option locks the current record.
No other concurrent access stream can access this record until it is
unlocked. Only this access stream can update this record. <>
- On Tru64 UNIX systems, for indexed files the START statement
(with or without the ALLOWING phrase) does not detect or acquire a
record lock on the current record. <>
- On Alpha and I64 systems, if X/Open file sharing is in effect, the
START statement does not detect or acquire a lock. <>
- If Hewlett-Packard standard record locking is in effect and the
ALLOWING or REGARDLESS option is not specified, the default behavior
for a START statement is that a lock is acquired if the file is opened
in I-O mode and locks are detected in any mode.
- On Alpha and I64, if ALLOWING or REGARDLESS is not specified,
there is potential for ambiguity regarding Hewlett-Packard standard
record locking or X/Open standard record locking. The selection of
X/Open standard (rule 19) or Hewlett-Packard standard (rule 20)
behavior is made as follows by the compiler:
- If (on Alpha and I64) X/Open standard syntax (LOCK MODE or WITH
(NO) LOCK) has been specified for file-name prior to the START
statement, the compiler interprets the statement according to the
X/Open standard.
- If Hewlett-Packard standard syntax (LOCK-HOLDING, ALLOWING, or
REGARDLESS) has been specified for file-name prior to the
START statement, the compiler interprets the statement according to the
Hewlett-Packard standard.
- If no file-sharing syntax (LOCK-HOLDING, ALLOWING, REGARDLESS,
LOCK MODE, or WITH [NO] LOCK) has been specified for file-name
prior to the START statement, then the compiler uses the
/STANDARD=[NO]XOPEN qualifier on OpenVMS Alpha and I64 (or the
Tru64 UNIX equivalent
-std [no]xopen
flag) to determine whether the START statement is interpreted as X/Open
or Hewlett-Packard standard: a setting of
xopen
selects the X/Open standard, whereas a setting of
noxopen
selects the Hewlett-Packard standard.
Any subsequent I-O locking syntax for the same file connector in
your program must be consistent: X/Open standard locking (Alpha, I64)
and Hewlett-Packard standard locking (implicit or explicit) cannot be
mixed for the same file connector.
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