6489P017.HTM
  OSSG Documentation
  22-NOV-1996 13:17:00.86

Copyright © Digital Equipment Corporation 1996. All Rights Reserved.

Legal

OpenVMS User's Manual

Examples

The following two examples use the default key.

1. In this example, the file NAMES.LST is sorted in ascending order:

   $ SORT NAMES.LST BYNAME.LST
   

   
   This command creates the ordered output file BYNAME.LST, as shown in Figure 11-1.

   Figure 11-1 List Sorted in Ascending Order

   ---

   

   ---

2. In this example, the files NAMES.LST and NAMES2.LST are sorted into the ordered output file BYNAME.LST. Sort treats the files as if they were one large file:

   $ SORT NAMES.LST,NAMES2.LST  BYNAME.LST
   

See Section 11.10 for a complete list of SORT qualifiers.

11.3.3 Defining a Key

Table 11-2 describes the five elements that comprise a key.

Table 11-2 /KEY Qualifier Values

Key Element	Value	Description
Key position	POSITION: n	The position of the first byte of the key field within the record. The first byte in a record is position 1. POSITION: n is required.
Key size	SIZE: n	The length of the key field. SIZE: n is required except for floating point data. The data type you specify for the key determines what values are acceptable when specifying size. The following table lists the possible values for each type of data and the units used to specify the size of the key. Data Valid Range Units Character 1 through 32,767 Characters Binary 1, 2, 4, 8, or 16 (For the high-performance Sort/Merge utility, the size of a binary data type key must be 1, 2, 4, or 8 bytes. Support of a 16-byte binary key is deferred to a future OpenVMS Alpha release.) Bytes Decimal 1 through 31 Digits Floating-point No value is necessary. For decimal data, if the decimal sign is stored in a separate byte, that byte is not counted toward the size of the data. If you specify a key that extends beyond the end of a record, Sort treats the missing characters as null characters.
Data type	CHARACTER	Character data. CHARACTER is the default data type.
	BINARY	Binary data. SIGNED --- Signed binary or decimal data. SIGNED is the default for binary and decimal data. UNSIGNED --- Unsigned binary or decimal data.
	F_FLOATING	F_FLOATING format data.
	D_FLOATING	D_FLOATING format data.
	G_FLOATING	G_FLOATING format data.
	H_FLOATING	On VAX systems, H_FLOATING format data. (Not currently supported by the high-performance Sort/Merge utility.)
	S_FLOATING	On Alpha systems, IEEE S_FLOATING format data.
	T_FLOATING	On Alpha systems, IEEE T_FLOATING format data.
	DECIMAL	Decimal data. TRAILING_SIGN --- Trailing sign decimal data. TRAILING_SIGN is the default for decimal data. LEADING_SIGN --- Leading sign decimal data. The leading sign must be in the first position of the field and the field must be left zero padded. OVERPUNCHED_SIGN --- Overpunched decimal data. OVERPUNCHED_SIGN is the default for decimal data. SEPARATE_SIGN --- Separate sign decimal data.
	ZONED	Zoned decimal data. (Not currently supported by the high-performance Sort/Merge utility.)
	PACKED_DECIMAL	Packed decimal data.
Sort order	ASCENDING	Orders the sorting operation in ascending alphabetical or numerical order. ASCENDING is the default order.
	DESCENDING	Orders the sorting operation in descending alphabetical or numerical order.
Key priority	NUMBER: n	Specifies the order of priority of each key if you do not list multiple keys in the order of their priority. A value of 1 to 255 can be specified.

If the data in the key fields is not character data, you must specify the data type. The following data types are recognized by the Sort/Merge utility:

BINARY, [SIGNED]
BINARY, UNSIGNED
CHARACTER
DECIMAL, LEADING_SIGN, SEPARATE_SIGN [SIGNED]
DECIMAL, LEADING_SIGN, [OVERPUNCHED_SIGN, SIGNED]
DECIMAL [,SIGNED, TRAILING_SIGN, OVERPUNCHED_SIGN]
DECIMAL, [TRAILING SIGN], SEPARATE_SIGN, [SIGNED]
DECIMAL, UNSIGNED
D_FLOATING
F_FLOATING
G_FLOATING
H_FLOATING
S_FLOATING, IEEE (Alpha systems only)
T_FLOATING, IEEE (Alpha systems only)
PACKED_DECIMAL
ZONED

The items in brackets are defaults and need not be specified.

Note

For decimal string data, the Sort/Merge utility reports an invalid digit in the input string differently for VAX and Alpha systems. On VAX systems, you receive a message that the invalid digit (or reserved operand) is converted to a valid decimal string for comparison purposes. On Alpha systems, Sort/Merge performs the same conversion but does not display a message. In both cases, the data from the input file is written to the output file without change.

Examples

In Figure 11-2, each record in the file EMPLOYEE.LST consists of three fields: (1) a department name, (2) an account number, and (3) a customer name.

Figure 11-2 Record Fields in a List

The following examples illustrate how to sort the records in EMPLOYEE.LST both with, and without, a key field:

1. In this example, EMPLOYEE.LST is sorted by account number, using the /KEY qualifier to describe the account number field:

   $ SORT/KEY=(POSITION:5,SIZE:4,DECIMAL)  EMPLOYEE.LST BILLING1.LST
   

   
   This command specifies that the key field (the account number) starts in position 5, is 4 characters long, contains decimal data, and should be sorted in ascending order (the default). Figure 11-3 shows the results of this Sort operation.

   Figure 11-3 Sorting by Key Field

   ---

   

   ---

2. This example shows how to sort the file EMPLOYEE.LST without specifying a key field:

   $  SORT EMPLOYEE.LST BYDEPT.LST
   

   
   Because no key is specified, Sort assumes the default characteristics. Figure 11-4 shows the result of this Sort operation.

   Figure 11-4 Sorting with Default Key Records

   ---

   

   ---

   
   Sort treats each record in EMPLOYEE.LST as one key of character data. In this example, each record includes a department name, an account number, and a customer name. If Sort finds a duplicate department name, it sorts the names by account number. If it then finds a duplicate account number, it sorts by customer name. Note that the account number is part of the record. Unless you specify otherwise, it is treated as character data.

You can sort with more than one key (up to a limit of 255 keys). You can specify multiple keys in order of their priority with the primary key first, the secondary key next, and so on. Alternately, you can specify a key's priority using NUMBER:n. Each key can be ascending or descending.

Examples

1. In the following example, the file EMPLOYEE.LST is sorted by the customer name key first and then (where there are identical names), by the account number:

   $  SORT /KEY=(POSITION:10,SIZE:15,CHARACTER) -
   _$ /KEY=(POSITION:5,SIZE:4,DECIMAL) EMPLOYEE.LST BILLING2.LST
   

   
   Figure 11-5 shows the results of this Sort operation.

   Figure 11-5 Sorting with Multiple Key Fields

   ---

   

   ---

2. In the following example, records are sorted first by the department name in descending order, then by the customer name in ascending order:

   $ SORT/KEY=(POSITION:1,SIZE:3,DESCENDING) -
   _$ /KEY=(POSITION:10,SIZE:15) -
   _$ EMPLOYEE.LST BILLING3.LST
   

   
   Figure 11-6 shows the results of this Sort operation.

   Figure 11-6 Sorting with Multiple Key Fields (Ascending and Descending Order)

   ---

   

   ---

By default, Sort/Merge keeps records with identical key fields but does not necessarily maintain the same order in which they appeared in the input file. To control the way in which records with identical keys are sorted, specify one of the following qualifiers:

• /STABLE
  Maintains the input order of records with identical keys. If you use this qualifier when sorting multiple input files, on output, records with equal keys in the first file precede those from the second file and so on.
• /NODUPLICATES
  Retains only one copy of records with identical keys. If you want to specify which duplicate record to keep, invoke Sort at the program level and specify an equal-key routine.

The /STABLE and /NODUPLICATES qualifiers are incompatible. You cannot specify both qualifiers on the same command line.

Example

In the following example, records with duplicate account numbers are eliminated from the file EMPLOYEE.LST:

$  SORT /KEY=(POSITION:5,SIZE:4)/NODUPLICATES EMPLOYEE.LST BUDGET.LST

Figure 11-7 shows the results of this Sort operation.

Figure 11-7 Sorting with Identical Key Fields

If you sort records that contain items other than character data, specify the data type of each key. In addition, take care in calculating starting positions and sizes because the items being compared can occupy more than 1 byte.

Example

If you are sorting a file that contains 20 characters followed by 3 floating-point numbers in F_floating format, the positions are as follows:

• The character data occupies positions 1 to 20 (20 characters).
• The first F_floating-point number occupies positions 21 to 24.
• The second F_floating-point number occupies positions 25 to 28.
• The third F_floating-point number occupies positions 29 to 32.

To sort the file by the third floating-point number, specify the key field as follows:

$ SORT/KEY=(POSITION:29,F_FLOATING) STATS.RAW STATS.SOR

You do not need to specify the size of the floating-point number because it is fixed at four bytes.

11.3.7 Output File Organization

By default, Sort produces an output file with the same file organization as that of the first input file. To specify a different output file organization, include one of the following qualifiers after the output file specification on the Sort command line:

• /FORMAT (record format)
  When you use this output qualifier, you can define the file record format, length, and block size.
• /INDEXED_SEQUENTIAL
  (The high-performance Sort/Merge utility does not support indexed sequential output file organization. Implementation of this feature is deferred to a future OpenVMS Alpha release.)
  Using this qualifier, you can define the output to have indexed sequential file organization. If you specify indexed sequential as the output file organization, you must also do the following:
  • Before you perform the Sort operation, create an empty file to be used as the output file. Sort requires an output file that already exists and is empty.
  • Include the /OVERLAY qualifier after the name of the output file on the SORT command line. The /OVERLAY qualifier indicates the existing file is to be overlaid with the sorted records of the input file.
• /RELATIVE
  Using this qualifier, you can define the output to have relative file organization.
• /SEQUENTIAL
  Using this qualifier, you can define the output to have sequential file organization.

Example

In the following example, a sequential file is produced after the indexed sequential file EMPLOYEE.LST is sorted:

$ SORT/KEY=(POSITION:10,SIZE:15) -
_$ EMPLOYEE.LST BYNAME.LST/SEQUENTIAL

Sort arranges files using one of the internal processes: record, tag, address, or indexed. (The high-performance Sort/Merge utility supports only the record process. Implementation of tag, address, and index processes is deferred to a future OpenVMS Alpha release.) The process you specify can affect the efficiency of the Sort operation. Refer to Section 11.9 for information about optimizing a Sort or Merge operation.

The following table describes the four types of process. Use the /PROCESS=type qualifier to specify the sort process.

Sort Process	type	Description
Record	RECORD	Keeps records intact while sorting and produces an output file consisting of complete records. Record is the default sorting process.
Tag	TAG	Sorts the key fields only and then rereads the input file to produce an output file of complete records. The net result is the same as for a complete record sort. A tag sort is useful if disk space is low because it typically uses less work file space during the sorting. In most cases, a tag sort is slower than a record sort because it requires extra time to reread the input file.
Address	ADDRESS	Sorts the key fields only and produces an output file that is an index of record file addresses (RFAs) in binary format. An address sort is faster than a record sort but you must write a program to associate the record addresses with the records of the input file.
Indexed	INDEX	Sorts the key fields only and produces an output file of keys and RFAs (in binary format). As with an address sort, an index sort is faster than a record sort, but you must write a program to associate the record addresses with the records of the input file.

11.4 Specifying a Collating Sequence

("A"-"L","LL","M"-"Z")
      

      

Note

Exercise caution when using the multinational collating sequence to sort or merge files for further processing. Sequence-checking procedures in most programming languages compare numeric characters. Normal sequence checking does not work because the multinational sequence is based on actual graphic characters, not the codes representing those characters.

The following examples demonstrate the creation of user-defined collating sequences for use in specification files. See Section 11.8 for information about specification files.

1. /COLLATING_SEQUENCE=(SEQUENCE=ASCII,IGNORE=("-"," ")) 
   

   
   This /COLLATING_SEQUENCE qualifier with an IGNORE option specified results in the following fields being compared as equal before tie breaking:

          252-3412 
          252 3412 
          2523412 
   

2. /COLLATING_SEQUENCE=(SEQUENCE=("A"-"L","LL","M"-"R","RR","S"-"Z")) 
   

   
   This /COLLATING_SEQUENCE qualifier defines a sequence in which the double character LL collates as a single character between L and M, and the double character RR collates as a single character between R and S. These double characters would otherwise appear in their usual alphabetical order. By default, this user-defined sequence does not define any other characters, such as lowercase a to z.

Batch jobs are programs or DCL command procedures that run independently of your current session. If you are sorting large files, consider submitting the Sort operation as a batch job because the sort will require some time. See Chapter 18, Chapter 15 and Chapter 16 for more information about batch jobs and command procedures.

11.5.1 Command Procedures

Specify the SORT command in your command procedure just as you would write it on the screen. If your default directory does not contain the files to be sorted, explicitly set your default directory in the command procedure or include the directory in the command file specifications.

Example

The following example submits the DCL command procedure SORTJOB.COM as a batch job. The text of the command procedure is shown following the command line:

$ SUBMIT SORTJOB

! SORTJOB.COM 
! 
$ SET DEFAULT [USER.PER]   ! Set default to location of input files 
$ SORT/KEY=(POSITION:10,SIZE:15) EMPLOYEE.LST BYNAME.LST 
$ TYPE BYNAME.LST 
$ EXIT 

You can include the input records in the batch job by placing them after the SORT command with one record per line. Individual sort records can be longer than one line.

As with terminal input of records, specify the input file parameter as SYS$INPUT. Use the /FORMAT qualifier to specify the record size in bytes and the approximate file size in blocks. Approximately six 80-character lines equal one block.

Example

The following example demonstrates including input records in a command procedure:

$ SUBMIT SORTJOB

! SORTJOB.COM 
! 
$ SET DEFAULT [USER.PER] 
$ SORT/KEY=(POSITION:10,SIZE:15) - 
SYS$INPUT- 
/FORMAT=(RECORD_SIZE:24,FILE_SIZE:10) - 
BYNAME.LST 
$ DECK 
BST 7828 MCMAHON JANE 
ADM 7933 ROSENBERG HARRY 
COM 8102 KNIGHT MARTHA 
ANS 8042 BENTLEY PETER 
BIO 7951 LOWELL FRANK 
$ EOD 

The following sections describe how to merge files.

11.6.1 MERGE Command

The MERGE command combines up to 10 (the high-performance Sort/Merge utility supports up to 12) sorted files into one ordered output file. You can merge input files that have the same format and have been sorted by the same key fields.

By default, Merge checks the sequence of the records in the input files to be sure they are in order. Specify the /CHECK_SEQUENCE qualifier if you want Merge to check the order. If you specify this qualifier and a record is out of order (for example, if you have not sorted one of the input files), Merge reports the following error:

%SORT-W-BAD_ORDER, merge input is out of order 

You can use the same qualifiers with the MERGE command as you use with the SORT command with two exceptions:

• You cannot specify a process (/PROCESS) for a Merge operation.
• The /CHECK_SEQUENCE qualifier is used only for a merge operation.

Example

In the following example, the files BYNAME1.LST and BYNAME2.LST have already been sorted by customer name in ascending order. The command shown merges them:

$ MERGE BYNAME1.LST,BYNAME2.LST BYNAME3.LST

The output file BYNAME3.LST contains all the records from both files, BYNAME1.LST and BYNAME2.LST, as shown in the following figure:

To merge files that are sorted using a specific key, you must specify the same key with the /KEY qualifier on the MERGE command line.

If you do not specify a key, Merge uses the default key described in Section 11.3.2.

Example

In the following example, the files BILLING1.LST and BILLING4.LST were sorted by account number (/KEY=POSITION:5,SIZE:4,DECIMAL). To merge the files into the output file MAILING.LST, enter the following command line:

$ MERGE/KEY=(POSITION:5,SIZE:4,DECIMAL) -
_$ BILLING1.LST,BILLING4.LST MAILING.LST 

The results of the merge are as follows:

If you want to merge files that you know are in sorted order, you can prevent sequence checking by specifying the /NOCHECK_SEQUENCE qualifier.

11.6.3 Identical Key Fields

As with a Sort operation, when input files contain records with identical key fields, Merge does not necessarily maintain the same order in which the records had appeared in the input file. To maintain the input order of records with identical keys, specify the /STABLE qualifier on the MERGE command line. To retain only one copy of records with identical keys, specify the /NODUPLICATES qualifier.

11.7 Entering Records from a Terminal

Records that you want to sort or merge do not have to be in a file. You can enter the records directly from the terminal as you enter the SORT or MERGE command. The following table describes the procedure: Previous | Next | Contents