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Natural 4 Fundamentals Part II Manipulating Natural data

Boston University. 2. Date/time masks. DD Day. MM Month. YYYY Year, 4 digits. YY Year, 2 digits. WW Number of Week.JJJJulian day. N(n) Name of Day (language-dependent). ONumber of week day L(n) Name of Month (language-dependent). R Year in Roman numerals (maximum 13 digits). . Bo

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Natural 4 Fundamentals Part II Manipulating Natural data

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    1. Boston University 1 Natural 4 Fundamentals Part II – Manipulating Natural data Boston University at a Glance 4th largest educational and research institution 30,000 under-graduate, graduate and other students 17 schools and colleges across two campuses 1 hospital - Boston University Medical Center 3,321 full/part time faculty members 8,538 full/part time employees 1.19 billion dollar annual operating budget 930.2 million dollar endowment 52 developers and support staff in applications 3 application and 4 technical DBA’s 3 DBMS - DB2, ADABAS, and Oracle * data as of April 2001 Boston University at a Glance 4th largest educational and research institution 30,000 under-graduate, graduate and other students 17 schools and colleges across two campuses 1 hospital - Boston University Medical Center 3,321 full/part time faculty members 8,538 full/part time employees 1.19 billion dollar annual operating budget 930.2 million dollar endowment 52 developers and support staff in applications 3 application and 4 technical DBA’s 3 DBMS - DB2, ADABAS, and Oracle * data as of April 2001

    2. Boston University 2 Date/time masks DD Day. MM Month. YYYY Year, 4 digits. YY Year, 2 digits. WW Number of Week. JJJ Julian day. N(n) Name of Day (language-dependent). O Number of week day L(n) Name of Month (language-dependent). R Year in Roman numerals (maximum 13 digits).

    3. Boston University 3 Affect of DTFORM setting The profile parameter DTFORM determines whether Monday or Sunday is considered the first day of the week. With DTFORM=U : Sunday = 1, Monday = 2, … With DTFORM=other : Monday = 1, Tuesday = 2, … This has an affect on the EM=O

    4. Boston University 4 Date Checking Several customers utilize code similar to the following and have requested a written explanation of the difference between the valid dates for MASK statements versus MOVE EDITED statements. RESET field1(A8) field2(D) INPUT field1 IF field1 = MASK(YYYY) THEN MOVE EDITED field1 TO field2 (EM=YYYY) ELSE DISPLAY 'error in date field' END-IF As documented in the NATURAL Reference Manual, the MASK (YYYY) checks for a valid date between 0000 and 2699. The MOVE EDITED statement, however, checks for a valid Gregorian date. Keep in mind the Gregorian year begins in 1582; therefore, the date in the MOVE EDITED statement must begin with the year 1582 or greater. If the date is not 1582 or greater, you will receive a NAT1143 error.

    5. Boston University 5 Date Checking In order to avoid receiving the NAT1143 error, there are three possible coding methods: Write a check in the program (or processing rule) for YEAR >=1582 and YEAR <=2699. Add an ON ERROR routine which captures the NAT1143 error and issues back to the end-user a 'friendly' message stating the year (on the MOVE EDITED statement) must begin with the year 1582 or greater. Place text on the INPUT statement stating that the year to be input must begin with the year 1582 or greater.

    6. Boston University 6 Mask Testing MASK (N) - F0 thru F9 MASK (Z) - 'correct' hex character in last nibble position - 'C', 'F', (positive) 'D' (negative) MASK (D) - legal date according to DTFORM (use *DATX) MASK (T) - legal time according to DTFORM MASK (E) - legal date & time MASK (YYYY) – checks valid 4-char. Year MASK (C) – checks for alphanumeric MASK (S) – checks special characters MASK (U) – checks upper case MASK (L) – checks lower case Testing 1.     IF FIELD = MASK … 2.     The IS operator IF FIELD IS (N4) or IF FIELD IS (D) 3. IF #CV MODIFIED Testing 1.     IF FIELD = MASK … 2.     The IS operator IF FIELD IS (N4) or IF FIELD IS (D) 3. IF #CV MODIFIED

    7. Boston University 7 Example of interesting use of MASK(S) How do you determine if an alphanumeric field contains a special character? Natural provides a test for a special character, but surprises are in order ! 1 #EXCL (A1) CONST <'!'> * IF #EXCL = MASK (S) WRITE 'AN EXCLAMATION IS A SPECIAL CHARACTER.' ELSE WRITE 'AN EXCLAMATION IS NOT A SPECIAL CHARACTER TO NATURAL.' END-IF DEFINE DATA LOCAL 1 #CHARS(A1/25) INIT (V) <'!','@','#','$','%','¬','&','*','(',')',’-‘,’_’,’+','<', '>','?','/','\','{','}','~','`','=','˘','|'> 1 #I (P3) 1 #EXCL (A1) CONST <'!'> END-DEFINE * IF #EXCL = MASK (S) WRITE 'AN EXCLAMATION IS A SPECIAL CHARACTER.' ELSE WRITE 'AN EXCLAMATION IS NOT A SPECIAL CHARACTER TO NATURAL.' END-IF * FOR #I = 1 25 IF #CHARS(#I) = MASK (S) WRITE #I #CHARS(#I) 'IS A SPECIAL CHARACTER' ELSE WRITE #I #CHARS(#I) 'IS NOT A SPECIAL CHARACTER.' END-IF END-FOR ENDDEFINE DATA LOCAL 1 #CHARS(A1/25) INIT (V) <'!','@','#','$','%','¬','&','*','(',')',’-‘,’_’,’+','<', '>','?','/','\','{','}','~','`','=','˘','|'> 1 #I (P3) 1 #EXCL (A1) CONST <'!'> END-DEFINE * IF #EXCL = MASK (S) WRITE 'AN EXCLAMATION IS A SPECIAL CHARACTER.' ELSE WRITE 'AN EXCLAMATION IS NOT A SPECIAL CHARACTER TO NATURAL.' END-IF * FOR #I = 1 25 IF #CHARS(#I) = MASK (S) WRITE #I #CHARS(#I) 'IS A SPECIAL CHARACTER' ELSE WRITE #I #CHARS(#I) 'IS NOT A SPECIAL CHARACTER.' END-IF END-FOR END

    8. Boston University 8 Questionable Use of IS

    9. Boston University 9 Suggestion to add… Consider adding … DEFINE DATA LOCAL 1 #F (A10) 1 REDEFINE #F 2 #F2 (N10) 1 #N (P10) END-DEFINE * ASSIGN #F = ‘123453789' IF #F IS (N10) #N := VAL(#F) WRITE ‘NUMERIC VALUE TO USE.’ #N ELSE WRITE 'DATA FIELD ERROR, DO NOT USE IT’ #F END-IF END

    10. Boston University 10 How to Test for Packed? 1). Always use the Packed field name in the MASK statement. 2). Do NOT use the name of an Alpha field which is either a redefinition of the packed field, or the field the Packed field redefines. 3). In the MASK, specify the total number of digits the Packed field can contain, making the last one a "Z" in the MASK. A violation of the above three points will result in an incorrect result.

    11. Boston University 11 Date mask problem The MASK (YYYY) checks for a valid date between 0000 and 2699. The MOVE EDITED statement checks for a valid Gregorian date, which begins in 1582. Therefore, the date in the MOVE EDITED statement must begin with the year 1582 or greater. If the date is not 1582 or greater, you will receive a NAT1143 error.

    12. Boston University 12 Avoiding NAT1143 Three possible coding methods: Write a check in the program (or processing rule) for YEAR >=1582 and YEAR <=2699. Add an ON ERROR routine which captures the NAT1143 error and issues back to the end-user a 'friendly' message stating the year (on the MOVE EDITED statement) must begin with the year 1582 or greater. Place text on the INPUT statement stating that the year to be input must begin with the year 1582 or greater.

    13. Boston University 13 Array definitions Arrays are fundamentally data elements arranged in tables; elements in a table are represented by a single variable name. You can define up to 3 dimensions. Higher level dimensions can be simulated. Quiz: What is the meaning of:   DEFINE DATA LOCAL 1 #ROW (A5/4) 1 #COLUMN (A10/2:8) END-DEFINE What [if any] is the difference between these two definitions? DEFINE DATA LOCAL 1 PRJT-T (1:10) 2 PROJ-ID (A4) 2 USER-T (1:10) 3 USER-ID (A6) 3 FUNC-T (1:10) 4 FUNC-CD (A2) END-DEFINE and DEFINE DATA LOCAL 1 PRJT-T (1:200) 2 PROJ-ID (A4) 2 USER-ID (A6) 2 FUNC-CD (A2) END-DEFINE What [if any] is the difference between these two definitions? DEFINE DATA LOCAL 1 PRJT-T (1:10) 2 PROJ-ID (A4) 2 USER-T (1:10) 3 USER-ID (A6) 3 FUNC-T (1:10) 4 FUNC-CD (A2) END-DEFINE and DEFINE DATA LOCAL 1 PRJT-T (1:200) 2 PROJ-ID (A4) 2 USER-ID (A6) 2 FUNC-CD (A2) END-DEFINE

    14. Boston University 14 Arrays definitions continued… Database arrays M 2 AG ADDRESS-LINE A 20 N : P 1 AQ INCOME 2 AR CURR-CODE A 3 N HD=CURRENCY/CODE 2 AS SALARY P 9.0 N HD=ANNUAL/SALARY M 2 AT BONUS P 9.0 N   For MU inside Pes, an example of coding for occurrences is:   1 STAFF VIEW OF EMPLOYEES 2 PERSONNEL-ID 2 NAME 2 SALARY (1:6) 2 CURR-CODE (1:6) 2 BONUS (1:6,1:6) How does one decide to use ‘P’ vs. ‘N’ format for numeric values in a DDM? Is there any difference?How does one decide to use ‘P’ vs. ‘N’ format for numeric values in a DDM? Is there any difference?

    15. Boston University 15 A consideration of a performance issue for Adabas access Database packed definitions on DDM view 1 AA STAFF-ID A 10 N : 1 AQ PERSONAL-DATA 2 AR STATE-CODE A 4 N 2 AS BLDG-ID N 5.0 N 2 AT DATE-OF-BIRTH N 8.0 N 2 AU OVERDUE-LIBR-BOOK-QTY P 3.0 N 2 AV SALARY-AMT P 8.0 N

    16. Boston University 16 Some performance considerations Do integer arithmetic with I definitions first, P second. Also good for cross platform formatting. Keep literal assignments and variables the same length! Use EXAMINE on arrays vs. FOR loops wherever possible For complex computations, normalize data element (type and length). Avoid mix mode expressions. RESET instead of MOVE

    17. Boston University 17 Arithmetic operations Simple - use integer or packed for arithmetic, and there is no difference in performance between Formula computations and individual arithmetic statements whose sum performance is equivalent to a formula.   The packed notion becomes more suspect if you have cross platform Natural requirements. Packed is restricted to S/390 instruction machines.The packed notion becomes more suspect if you have cross platform Natural requirements. Packed is restricted to S/390 instruction machines.

    18. Boston University 18 Natural Math. Functions Operation Function Comment Addition + Subtraction - Multiplication * Division / Exponentiation ** integer exponents only Square root SQRT operand cannot be an expression, NATURAL evaluates negative operands as positive Use of square root function: * SUBPROGRAM: STNDDEV * FUNCTION: COMPUTE STANDARD DEVIATION * ---------------------------------------------------------- * ALGORITHM: STAND. DEV. = SQUARE ROOT (VARIANCE) * VARIANCE = SUM OF SQUARE OF DIFFERENCES BETWEEN * EACH DATUM AND AVERAGE * ---------------------------------------------------------- * EJECT DEFINE DATA PARAMETER 1 #ARR-ELT (P8.3/1:V) /* INPUT 1 #ARRAY-LENGTH (I4) /* INPUT 1 #STND-DEV (P10.3) /* OUTPUT 1 #VARIANCE (P10.3) /* OUTPUT LOCAL 1 #AVERAGE (P10.3) 1 #NUM (P8.3) 1 #TOTAL (P12.3) 1 #I (I4) END-DEFINE * SKIP 1 #ARRAY-LENGTH := *OCCURRENCE (#ARR-ELT) FOR #I = 1 TO #ARRAY-LENGTH #TOTAL := #TOTAL + #ARR-ELT (#I) END-FOR * SKIP 1 COMPUTE #AVERAGE = #TOTAL / #ARRAY-LENGTH * FOR #I = 1 TO #ARRAY-LENGTH #NUM := #ARR-ELT (#I) #TOTAL := #TOTAL + (#AVERAGE - #NUM) ** 2 END-FOR * SKIP 1 #VARIANCE := #TOTAL / #ARRAY-LENGTH #STND-DEV := SQRT (#VARIANCE) ESCAPE ROUTINE ENDUse of square root function: * SUBPROGRAM: STNDDEV * FUNCTION: COMPUTE STANDARD DEVIATION * ---------------------------------------------------------- * ALGORITHM: STAND. DEV. = SQUARE ROOT (VARIANCE) * VARIANCE = SUM OF SQUARE OF DIFFERENCES BETWEEN * EACH DATUM AND AVERAGE * ---------------------------------------------------------- * EJECT DEFINE DATA PARAMETER 1 #ARR-ELT (P8.3/1:V) /* INPUT 1 #ARRAY-LENGTH (I4) /* INPUT 1 #STND-DEV (P10.3) /* OUTPUT 1 #VARIANCE (P10.3) /* OUTPUT LOCAL 1 #AVERAGE (P10.3) 1 #NUM (P8.3) 1 #TOTAL (P12.3) 1 #I (I4) END-DEFINE * SKIP 1 #ARRAY-LENGTH := *OCCURRENCE (#ARR-ELT) FOR #I = 1 TO #ARRAY-LENGTH #TOTAL := #TOTAL + #ARR-ELT (#I) END-FOR * SKIP 1 COMPUTE #AVERAGE = #TOTAL / #ARRAY-LENGTH * FOR #I = 1 TO #ARRAY-LENGTH #NUM := #ARR-ELT (#I) #TOTAL := #TOTAL + (#AVERAGE - #NUM) ** 2 END-FOR * SKIP 1 #VARIANCE := #TOTAL / #ARRAY-LENGTH #STND-DEV := SQRT (#VARIANCE) ESCAPE ROUTINE END

    19. Boston University 19 Natural Math. Functions continued… Absolute value ABS (X) Arctangent ATN (X) Cosine COS (X) Exponential function EXP (X) Fractional part of field FRAC (X) Integer part of field INT (X) NATURAL log (base e) LOG (X) Sign of field SGN (X) returned values are -1,0,+1 Sine SIN (X) Tangent TAN (X) Extract num. value from alpha VAL (X) Returns B4 return code RET (X) 'X' is a user program, invoked via CALL Internal unique field rep. POS (X) 'X' is a field name 1. For those not familiar with the exponential function, it returns a value in base e. For example, #Y = EXP(#X), where #X = 2, returns a value of 7.38905 because it is approximately e, which the Calculus teaches us is approximately 2.71828, to the power of 2. 2. Currently, none of the functions can be referenced in a WRITE/DISPLAY statement without getting a NAT0044 error. Also, it is documented that the format and length of the resultant takes on the characteristics of the operand to the function. I do not believe this fact is documented correctly. In my attempt to conclude if the trig functions took radian or degree measure, I wrote the following example: 0010 #X (P4) = 45 0020 #Y (P2.6) = SIN (#X) 0030 WRITE #Y 0040 END  If the documentation were correct, I would expect the result to be of format/length P4, but in fact the result was recorded with 6 position fractional accuracy. This implies that the result is actually the “largest and most accurate” of any operand in the compute statement. 1. For those not familiar with the exponential function, it returns a value in base e. For example, #Y = EXP(#X), where #X = 2, returns a value of 7.38905 because it is approximately e, which the Calculus teaches us is approximately 2.71828, to the power of 2. 2. Currently, none of the functions can be referenced in a WRITE/DISPLAY statement without getting a NAT0044 error. Also, it is documented that the format and length of the resultant takes on the characteristics of the operand to the function. I do not believe this fact is documented correctly. In my attempt to conclude if the trig functions took radian or degree measure, I wrote the following example: 0010 #X (P4) = 45 0020 #Y (P2.6) = SIN (#X) 0030 WRITE #Y 0040 END  If the documentation were correct, I would expect the result to be of format/length P4, but in fact the result was recorded with 6 position fractional accuracy. This implies that the result is actually the “largest and most accurate” of any operand in the compute statement.

    20. Boston University 20 Notes on Math. Functions Lastly, the trig functions take the values of its operands as radian measure, not degree measure. The ”best” conversion formula to use in NATURAL is RAD = PI * DEG / 180.0 where PI is defined as a CONST of value 3.14157, DEG is defined to contain the degree measure (e.g., P4 format). NATURAL logs can be converted to common logs (base 10) using the simple formula: Common LOG(X) = NATURAL LOG (X) / NATURAL LOG 10

    21. Boston University 21 Two important array operations Sorting arrays - See example Searching arrays  

    22. Boston University 22 Search – Use EXAMINE DEFINE DATA LOCAL 1 #PGM-ARRAY (A8/500) 1 #INDEX (P4) 1 #SEARCH-FIELD (A8) END-DEFINE   #SEARCH-FIELD = 'TAL0530N' EXAMINE #PGM-ARRAY(*) FOR #SEARCH-FIELD GIVING POSITION #INDEX   BEWARE!! There is one issue for which care must be taken in searching lists. If the search string is shorter than the occurrences, the wrong EXAMINE statement can return unexpected results. You must use an EXAMINE statement with the FULL option for both the search field and the array to guarantee returning the correct count.   BEWARE!! There is one issue for which care must be taken in searching lists. If the search string is shorter than the occurrences, the wrong EXAMINE statement can return unexpected results. You must use an EXAMINE statement with the FULL option for both the search field and the array to guarantee returning the correct count.

    23. Boston University 23 Date Arithmetic Operation Result 1. (D) + (D) not allowed 2. (T) + (T) (T) 3. (D) + integer (D) 4. (T) + integer (T) 5. (D) + (T) (T) 6. (D) – (D) integer, in days 7. (T) – (T) integer, in tenths of seconds 8. (D) – integer (D) 9. (T) – integer (T) 10. (D) – (T) integer, in tenths of seconds 11. (T) – (D) integer, in tenths of seconds Integer values can be of formats N, P, or I. Integer values can be of formats N, P, or I.

    24. Boston University 24 Date arithmetic continued… 0010 DEFINE DATA LOCAL 0020 1 #TIME (T) 0030 1 #DATE (D) 0040 1 #HOUR (P8) INIT <36000> /* TENTHS SECONDS IN 1 HOUR 0050 END-DEFINE 0060 * 0070 MOVE *TIMX TO #DATE 0080 MOVE *TIMX TO #TIME 0090 WRITE 'CURRENT DATE / TIME ' '=' #DATE '=' #TIME 0100 * 0110 ADD ( 36 * #HOUR ) TO #TIME 0120 MOVE #TIME TO #DATE 0130 WRITE 'DATE / TIME 36 HOURS PLUS ' '=' #DATE '=' #TIME 0140 * 0150 END How would you define a second? 01 #SECOND (P8) INIT <10> How would you define a second? 01 #SECOND (P8) INIT <10>

    25. Boston University 25 Date example 0010 DEFINE DATA LOCAL 0020 1 #TODAY (D) 0030 1 #FUTURE-DATE (D) 0040 1 #FUTURE-GREG-DATE (A8) INIT <‘09-10-30'> 0050 1 #CURRENT-DATE (A8) 0060 1 #DAYS-DIFFERENTIAL (P4) 0070 END-DEFINE 0080 #TODAY = *DATX 0090 MOVE EDITED #FUTURE-GREG-DATE TO 0100 #FUTURE-DATE (EM=YY'-'MM'-'DD) 0110 MOVE EDITED #TODAY (EM=YY'-'MM'-'DD) TO #CURRENT-DATE 0120 #DAYS-DIFFERENTIAL = #FUTURE-DATE - #TODAY 0130 WRITE 'THE NUMBER OF DAYS BETWEEN' #FUTURE-GREG-DATE 0140 'AND TODAY' #TODAY 'IS' #DAYS-DIFFERENTIAL 0150 END

    26. Boston University 26 Quiz DEFINE DATA LOCAL 1 #T (T) END-DEFINE * #T := *TIMX IF #T = D'2006-10-13' THRU D'2006-10-15' /* Friday thru Sunday WRITE 'WITHIN DATE RANGE' ELSE WRITE 'NOT WITHIN DATE RANGE' END-IF END  Why does the execution at 1:00 AM on the morning of October 15 would the result be: NOT WITHIN DATE RANGE

    27. Boston University 27 Quiz DEFINE DATA LOCAL 1 #DAY (A10) 1 #MONTH (A10) 1 #D (D) END-DEFINE #D := *DATX MOVE EDITED #D (EM=N(9)) TO #DAY What does this do? End of session. Questions? Comments?

    28. Boston University 28 Last Quiz question ! How can you tell how much data space is available to your session and how much you are using with execution?

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