1. 1 Chapter 14 - Sorting System Concepts –Sort key Major Key (Primary) Minor Key (Secondary) –Sort sequence Ascending - Low to high Descending – High to low

2. 2 Figure 14.1Sorting Vocabulary NAME YEARMAJOR Smith1Liberal arts Jones4Engineering Adams3Business Howe2Liberal arts Frank1 Engineering Zev4Business Benjamin 4Business Grauer3Liberal arts Crawford 2Engineering Deutsch4Business Makoske 1Business (a) Unsorted Data

3. 3 Primary Key: Name (Ascending) NAME YEARMAJOR Adams3Business Benjamin 4Business Crawford 2Engineering Deutsch4Business Frank1 Engineering Grauer3Liberal arts Howe2Liberal arts Jones4Engineering Makoske 1Business Smith1Liberal arts Zev4Business Figure 14.1 (b) Sorted Data, One Key

4. 4 Primary key: Year (descending) Secondary key: Name (ascending) NAME YEARMAJOR Benjamin 4Business Deutsch4Business Jones4Engineering Zev4Business Adams3Business Grauer3Liberal arts Crawford 2Engineering Howe2Liberal arts Frank1 Engineering Makoske 1Business Smith1Liberal arts Figure 14.1 Sorted Data, Two Keys

5. 5 Figure 14.1 Sorted Data, Three Keys Primary Key: major (Ascending) Secondary Key: year (Descending) Tertiary Key: name (Ascending) NAMEYEARMAJOR Benjamin 4Business Deutsch4Business Zev4Business Adams3Business Makoske 1Business Jones4Engineering Crawford 2Engineering Frank1 Engineering Grauer3Liberal arts Howe2Liberal arts Smith1Liberal arts

6. 6 –Collating Sequence (order of sorting) Alphabetic fields –Green vs. Greenfield Alphanumeric fields – 111 vs. AAA EBCDIC sequence – IBM Mainframe ASCII sequence – Most other computers

7. 7 EBCDIC (space).(period, decimal point) (greater than) ‘(apostrophe) =(equal sign) “(quotation mark) a through z (lower case) A through Z (upper case) 0 through 9 ASCII (space) “(quotation mark) $(currency symbol) ‘(apostrophe) ((left parenthesis) )(right parenthesis) *(asterisk) +(plus symbol),(comma) -(hyphen, minus symbol).(period, decimal point) /(slash) 0 through 9 ;(semicolon) (greater than) A through Z (upper case) a through z (lower case) Figure 14.2EBCDIC & ASCII Collating Sequences

8. 8 COBOL Implementation –SORT command Syntax INPUT PROCEDURE statement –Selective sorting –Sorting on calculated fields USING statement OUTPUT PROCEDURE statement –Use of temporary work file GIVING statement –Retention of sorted data

9. 9 SORT file-name-1 ON {DESCENDING KEY { data-name-1}... } ASCENDING} WITH DUPLICATES IN ORDER COLLATING SEQUENCE IS alphabet-name INPUT PROCEDURE IS procedure-name-1 USING {file-name-2} OUTPUT PROCEDURE IS procedure-name-2 GIVING {fine-name-3} SORT syntax

10. 10 Uses 3 files to sort –Input file – contains unsorted records –Output file – contains sorted records –Sort file – temporary file used by COBOL to sort the records First 2 must be defined in the FD section Sort file must be defined in a SD section

11. 11 Input File Sort Output File Sort file

12. 12 Ex.) SD SALESPERSON-SORT-FILE 01 SALESPERSON-SORT-RECORD 05 SP-REGION PIC 99. 05 SP-NUMBER PIC XXXX. 05 FILLER PIC X(52). … SORT SALESPERSON-SORT-FILE ON ASCENDING KEY SP-REGION SP-NUMBER USING SALESPERSON-INPUT-FILE GIVING SALESPERSON-OUTPUT-FILE

13. 13 SORT SALESPERSON-SORT-FILE ON DESCENDING KEY SP-REGION ON ASCENDING KEY SP-NUMBER USING SALESPERSON-INPUT-FILE GIVING SALESPERSON-OUTPUT-FILE

14. 14 Assume that the records in a file named X-FILE are to be sorted descending sequence by X-FIELD. The records in X-FILE are 40 characters long. X-FIELD is located in positions 8-12 and is alphanumeric. The file sorted output is called Y-FILE a. Code the SD entry and record description b. Code the sort statement c. Assume is should be sorted into ascending sequence by Y-FIELD and then into descending sequence by X- FIELD. Code the sort statements.

15. 15 The registrar has asked for a simple report listing students by year, and alphabetically within year. Thus all freshmen are to appear first, then sophomores..The incoming record has the follow layout: 01 STUDENT-RECORD. 05 ST-NAME PIC X(15). 05 ST-MAJOR PIC X(15). 05 ST-YEAR PIC XX. 05 ST-CREDITSPIC X(10). ST-YEAR USES FR,SO,JR AND GR. Develop the procedure division code to accomplish the desired sort.

16. 16 Merge statement