® IBM Software Group Enterprise COBOL Education Using Rational Developer for System Z COBOL Report Writing Patterns Jon Sayles, IBM Software Group, Rational Eco. Systems Team © 2006 IBM Corporation
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Course Contributing Authors § Thanks to the following individuals, for assisting with this course: 4 Bill Klein, Stephen Heffner/Pennington Associates 3
Purpose of This Document 4 Course Name: COBOL Foundation Training - with RDz 4 Course Description: Learn the COBOL language, RDz and learn z/OS terms, concepts and development skills in this course. 4 Pre-requisites: Some experience in a 3 rd or 4 th Generation Language is expected. SQL is also recommended. 4 Course Length: 10 days 4 Topics (Agenda) § § § § Getting Started - installing and configuring RDz - and the course materials, and using Eclipse to edit COBOL General Language Rules Basic COBOL Statements Advanced record and table handling Debugging Programs - Note: Deep dive on using RDz for common COBOL programming errors (001, 0 C 4, 0 C 7, infinite loops, fall-thru, etc. ) Input/Output and Report Writing Patterns COBOL Subprograms and the Linkage Section Structured Programming Concepts, professional COBOL development practices and Coding Patterns Advanced Character Manipulation, COBOL Intrinsic Functions, Date and Time coding patterns, and Language Environment calls OS/390 Concepts and JCL - Compile/Link & Run Procs on the mainframe Indexed file Coding Patterns Sort/Merge, Sequential File Match/Merge and Master File Update Coding Patterns Accessing DB 2 Data and DB 2 Stored Procedures COBOL in the Real World: – CICS - lecture only – IMS (DL/I and TM) - ditto – Batch processing - ditto – Java calling COBOL – COBOL and XML Statements – SOA and COBOL - creating and calling Web Services – Web 2. 0 using Rich UI 4
Course Details § Audience 4 This course is designed for application developers who have programmed in some language before, and who wish to learn COBOL. § Prerequisites 4 This course assumes that the student has the basic knowledge of IS technologies, data processing, software and have programmed for at least two or more years in a language such as: Java, VB, RPG, PL/1, Pascal, or some 4 th Generation Language or tool. 4 Knowledge of SQL (Structured Query Language) for database access is assumed as well. 4 Basic PC and mouse-driven development skills is also assumed. 4 Finally, it is assumed that you have been following along in this course, and have successfully completed the learning modules in sequence. § Or have the equivalent COBOL background obtained through some other form of COBOL study or on-the-job work. 5
Unit COBOL Report Writing Patterns Topics: § Report Writing Concepts § COBOL Print and Report Layouts § COBOL Control Break Reports § Appendices 6
COBOL Reporting – a Little History § Since its inception (the late 1950's) COBOL has been the dominant language of business application development § For the first 30 -40 years (yes, a COBOL application's shelf-life measure in decades what some application languages aspire towards, measured in years) businesses founded on COBOL used the language for: 4 Data capture and storage – using: § § Sequential files Indexed files Hierarchical databases Networked (CODASYL) and other pointer-based databases (such as Model 204) § Relational databases § Object databases 4 Reporting applications – both broad and deep, used in every aspect of the business world 4 Online applications 4 Batch (non-reporting) applications – data consolidation, computationally intensive applications, etc 4 Internet application § Now in its 6 th decade, COBOL applications still do all of the above – but certainly not in the same ratio and proportion they did in the 70's, 80's and 90's § In fact, one type of COBOL business application that is only marginally as important as it was in the past is the reporting application – specifically traditional print reports or "green bar" reports (See Slides) 7
Why Learn About COBOL Reporting Applications § Traditional reporting applications consumed a large portion of early COBOL practitioner time and attention 4 The COBOL language even has a REPORT SECTION – in the DATA DIVISION that provides special keyword vocabulary for creating reports § Business reports in fact were so critical to commercial shops that throughout the 1970's 1990's dozens of high-quality reporting products emerged on the market to simplify and streamline report development 4 Some by IBM 4 Many, many others – by 3 rd Party IBM Business Partners *** See Slide Notes § The reason for these non-COBOL/3 rd Party products was that essentially, Reporting Applications written in any general-purpose 3 rd generation computing language: 4 Are time-consuming and labor-intensive to create 4 Can be built from special-purpose tools and using proprietary report-programming languages: § Quickly § Cost-effectively 4 Often are time-dependent, in that unlike data, which has intrinsic and lasting value to organizations, reports are essential "the original" U. I. of business applications § And U. I. s have changed drastically since 1960 – haven't they § While the production source-code assets represented by the 3 rd Party products have not necessarily maintained their position, you will still most likely find the knowledge of how create COBOL reports useful for the following reasons: 4 You may end up writing a "quick-and-dirty" report against production data (these are sometimes called "one-offs" 4 You will most likely have to maintain and/or support COBOL reporting applications still running in production. 8
COBOL Reporting Applications – Big Picture § The figure below shows a typical COBOL reporting application, which contains the following elements: 4 A sorted sequential data source – one of the following: § On the mainframe a QSAM file – on the PC a "flat file" or sequential file § One the mainframe a VSAM or off the mainframe an indexed file – read sequentially § A database (IMS-DL/I, CA-IDMS, DB 2, or other) read sequentially 4 A program that processes records from the data source: § Read file – usually sequentially, until end-of-file § Validate/Compute each record, move fields § Write report – that there a few new COBOL WRITE clauses specific to reporting applications 4 A report – or report file, that is laid out according to precise U. I. record descriptions § And quite possibly a file of error records, produced by the COBOL program's validation routine COBOL Program Business Logic 9 Record Buffer Sorted Sequential File Record Buffer § We continue by looking at each part of the above Error Report
Sequential Input Files – For COBOL Reporting Applications § If you've been following along in this course you've already done a bit of work with Sequential Files. 4 Which are simple data structures that store records serially § Such that the records are read one after another § These records can be sorted or un-sorted. Sequential File – Sorted Sequential File - Unsorted RECORD 1……………. RECORD 5…………………………. RECORD 2……………. RECORD 3……………. RECORD 6…………………………. RECORD 4…………………………. RECORD 5……………. RECORD 6……………. RECORD 1……………. … … 4 We will cover sorting in an upcoming unit § COBOL Reports will just about always require the data to be sorted, and we will discuss various means of doing that in subsequent course sections: 4 COBOL internal sort 4 Operating System (JCL) sort 4 3 rd Party Sort packages § The data in the sorted sequential file records will be read into 01 record structures 4 Typically READ <file. Name> INTO <ws-Record. Name>. § The input record layouts correspond to the input data – which you've seen a number of times now 4 01 records § Group fields (levels 05 and higher) – Elementary fields, 88 levels, etc. 10
A Simple Report § Have a look at this report 1. 2. 3. § Let's break down the output or report-specific elements 1. Page Heading § § 4. This line should be at the top of each page Question … how will we know when to do a "Page Break"? § Answer: A page break should occur when the total # of lines written exceeds the max-lines-per-page print specification 2. Column Headings 4 These lines (sometimes the faux-underlines are there…sometimes they're not) should be just under the Page Heading 3. Detail Rows 4 We will format one row of output/detail report values for each input record 4. Report Footer § § This line is displayed at the end of the entire report. It would typically include additional report totals, counters and accumulators – although we have not coded for this in our example 11
Working Storage for the Simple Report § From the code shown here 4 Match each of the 01 s to the output shown (below) 4 One 01 is not shown in the report § You will add this in, when you do your work 4 Answer the following questions: § Why the VALUE SPACES next to the FILLER fields? § Are the report columns lined up? § What do you think the input for this report looks like? 12
Input Data and Record Layout for the Simple Report*** See Slide Notes § From the graphic below, note the input fields in the input file (Sorted Sequential File). § Map each field to its respective variable in Customer. Rec § Answer the following questions: 4 How many fields are there (total) – not counting the 10 -level break out of the date field? 4 Are any of the fields packed decimal or binary data? 4 Is the data as shown, sorted? § What "key" (what input field variable) is it sorted on § Ascending or Descending sort? Error Report Sorted Sequential File *** Slide Notes COBOL Program Business Logic 13
Procedure Division for the Simple Report § So – as this example is primarily: 4 Read Move to output file Write we can assume the logic is relatively straightforward 4 And? It is. § Read the code shown here, and follow the flow of control. Note the following: 4 File OPEN/CLOSE statements 4 Initial report heading and file read statements 4 Logic to perform the main business logic and report production paragraph until no more data. Within that paragraph: § Check for page break condition § Move statements from the input to the output variables § Write detail line: – AFTER ADVANCING LINE forces the printer to skip # lines between § Read next input record 4 Final Print Headings 14
Workshop – Sequential File Processing – 1 of 7 1. As you have done several times so far, Create a new, Workstation Local, COBOL project 4 Name it: chapter 4 § Be sure to select COBOL Sample Property Group 2. In the chapter 4 Project, create a new cobol folder (as shown) 3. Copy the COBOL source code from the Notes section of the slide 4. Create a new file in the chapter 4 project, in the cobol folder, named: rpt 1. cbl 5. Paste the code in the editor 6. Do a Local Syntax check of the program 7. Right-click and Nominate rpt 1 as the Entry Point 8. Rebuild the chapter 4 project 9. Expand the Build. Output folder, right-click and select Debug As > Debug Configurations 10. Setup a new Debug Configuration as shown 11. Debug the program § § Step to understand the code flow Resume (run) to end of program 12. Look at the output file produced (probably: c: customer. Out. dat) 15
Workshop – Sequential File Processing – 2 of 7 – Maintenance Specs Let's throw in some new specs for a "maintenance" workshop. To complete the work required, you will need to: 4 Edit the input records read. Only allow records with: § Valid numeric Customer. IDs § The year-in (YYYY) between 1990 and the current year – You will have to ACCEPT the CURRENT DATE into an 8 -byte date format (see code example in upcoming slide for an example of this) § All records in error should be written to a new error output file – unformatted 4 Add counters for: § § § # of error records found # of Good error records written Total # of input records read – the sum of this should equal the # of error records + the number of good records*** See Notes 4 Change Page Break to occur after 10 records 4 Fix the bug in the Active/Inactive output value – currently it's only writing I or A, and should write out Inactive or Active 4 See the next slide for an example new report 4 Use the values in the slide notes for new input test records § Sometimes known as test cases 4 Please read through all of the Workshop Slides before beginning to code. Note the use of PERFORM … THRU EXIT – which simplifies modifying logic 16
Workshop – 3 of 7 – Output Report Note the following: § Page #s at the bottom of each page § Statistics 17
Workshop – 4 of 7 – Environment and Data Division Note the following: 4 New file Select/Assign and FD for the Error records 4 Redefinition of Customer. ID – in order to do a numeric Class test on it 18
Workshop – 5 of 7 – Data Division and Procedure Division Note the following: 4 New value for Page. Brk. Req 4 New counters for records read/written, good, bad, indifferent, etc. 4 Current-Date variable and Aceppt statement 4 New file open/close/read/write 4 Added EXIT statements to the 100 paragraph, to simplify maintaining the code 19
Workshop – 6 of 7 Note the following: 4 Code for adding to the various record counters 4 New routine for handling the error records – inline within the current logic 4 New input edit sample Note the use of the following logic pattern: § Find an error § Deal with the error § Skip to the end of the function 20
Workshop – Sequential File Processing – 7 of 7 Suggested course of action: 4 Code the ENVIRONMENT, and DATA Division elements 4 Syntax check and Build the Project 4 Code the remaining PROCEDURE DIVISION logic § Use Content Assist to help you code references to the fields and records – This is why you'll do the data variable coding first 4 4 § Syntax check Build the Project Debug your program Run your program – and verify your work by reviewing the output files If time permits, add the following new requirements: 4 Additional Working Storage and output variables that count the # of Active and Inactive accounts 4 Add the current date to the top right-hand corner of the page, in ISO format 4 Move the page # to the top-left of each page 21
Unit COBOL Report Writing Patterns Topics: § Report Writing Concepts § COBOL Print and Report Layouts § COBOL Control Break Reports § Appendices 22
COBOL Report Writing Statements – WRITE AFTER ADVANCING Options § The SPECIAL-NAMES paragraph: 4 Relates IBM-specified environment-names to userdefined mnemonic-names. 4 Relates alphabetic-names to character sets or collating sequences. 4 Relates class names to sets of characters. 4 Specifies a substitute character for the currency sign. ENVIRONMENT DIVISION. CONFIGURATION SECTION. SOURCE-COMPUTER. IBM-370 -168. OBJECT-COMPUTER. IBM-370 -168. SPECIAL-NAMES. C 01 IS TO-TOP-OF-PAGE. … 01 01 In this example C 01 is a "special name" that is used with the WRITE I/O verb, to skip to the top of the next page when the output file is attached to a printer that accepts files formatted for printing (i. e. with special characters for advancing to the next physical page, etc. ). 01 HEADER-1. 05 FILLER 05 DATE-OUT 05 FILLER HEADER-2. 05 FILLER HEADER-3. 05 FILLER PIC PIC PIC X(12) Value X(21) VALUE X(03) Value 99/99/99. X(02) Value PIC X(08) PIC X(19) PIC X(17) Spaces. 'ANNUAL INCOME STATEMENT'. Spaces. VALUE 'EMPLOYEE'. Value Spaces. VALUE 'ANNUAL TAKE HOME'. PIC X(02) VALUE SPACES. PIC X(08) VALUE 'EMP-ID'. PIC X(24) VALUE SPACES. PIC X(03) VALUE 'SALARY'. … 700 -WRITE-REPORT-HEADING-LINES. WRITE EMPL-REPORT-REC FROM HEADER-1 § AFTER ADVANCING n LINES 4 Is a clause of the WRITE statement, that directs the printer to advance the next physical line in the report paper 4 Can specify AFTER or BEFORE 4 LINES is optional 4 Note the use of BEFORE ADVANCING 0 LINES – executed multiple times. § This is used to make a header or bold on a report 23 AFTER ADVANCING TO-TOP-OF-PAGE. WRITE EMPL-REPORT-REC FROM HEADER-2 AFTER ADVANCING 2 LINES. WRITE EMPL-REPORT-REC FROM HEADER-3 AFTER ADVANCING 1. … WRITE EMPL-REPORT-REC FROM TOTAL-LINE BEFORE ADVANCING 0 LINES.
Workshop – Open Ended One more maintenance assignment. We now have to account for four quarters worth of taxes (this program is run at end-of-year). 4 Replace the existing c: customer. In. data, with the records in the Slide Notes 4 Recode the input file's layout to match the new test case values 4 Create an output report that matches the next slide's screen capture 4 Add in one more statistic kept: § Average annual taxes paid (see next slide for snapshot of result) § You will have to be cognizant of: 4 Numeric output formatted fields 4 Lining up the columns of the report and the final average value 24
Workshop – Open Ended 25
Workshop Coding Solution § There is a coding solution to this simple report programming problem in the slide notes. § Considerations: 4 This is only one interpretation of how to do this workshop § It is offered here as – Caveat Emptor 4 If you choose to use this, we recommend you rename the program § So that if you want to finish your own version of this workshop you won't have to rename files, etc. § Optional 4 Add the State values into the output print (Rpt-Detail-Hdg-1 and Rpt-Detail-Hdg-2) lines 26
Unit COBOL Report Writing Patterns Topics: § Report Writing Concepts § COBOL Print and Report Layouts § COBOL Control Break Reports § Appendices 27
What Are Control Breaks? § A "Control Break" in COBL program vernacular, refers to a change in a control field value – typically in a sequential file, such that, upon successive reads when the value changes? A processing change happens in the program – and you would perform a routine that prints a control-break line containing: Summary values, sub-totals and/or statistics: § Lines counted – for all of the records since the last control break § Accumulators - numeric values such as: Number of items sold, Total expenses, etc. § Statistics – average, min, max salaries, etc. § The pre-requirement for Control Break functionality is for the sequential file to be sorted on the values in the control break field 4 Or there would be random control breaks in the output processing § Control Break reports are common in COBOL applications. They expose summary values and statistics, and help turn raw data into the information necessary to run a business. 4 Show me the total sales for our retail stores broken out by: § § State Store Departments Months of the year Individual stores 28
Single-Level Control Break Report – Example Break on U. S. State Values Note that the "control break" occurs: § Each time the State changes § And at the end of the report (an implied final control break) 29
What Are Control Breaks? § Do Initial Process Do Process All Records until end-of-file Do End-of-Program Process 4 Initial Process The pseudo-code for a § single-level Control § Break report is as follows Note that this logic could be divided up into COBOL paragraphs sections or simply inline routines – depending on the complexity and scope of each element § Write headers § Process first record § Move control break field to a hold-area (for comparison) 4 Process All Records § Edit – or Do Edit Routine § If good record – If Current control-break-value <> hold-control-break-value – Do Control Break Process – Process Detail Record – Read next input record 4 Process Detail Record § § § Add to hold fields and accumulators Move fields to output fields Write Detail Record 4 Control Break Process § § Move hold control break values to output fields Write Control Break Record Zero out control break hold areas Move Current control-break-value to hold-control-break-value 4 End-of-Program Process § Do final control break § Do final output report processing 30
COBOL Program to do Control Break – DATA DIVISION Areas – 1 of 3 § 2. Here's a completed example of a Control Break program. Note the following: 1. 2. 3. 4. Input record with two new fields for control break values (we will use only State. Code for this first part of the unit) The Control Break report line Hold areas for the Control Break interim -values The Control Break "hold keys" – that will be used to as comparison values with each new record read, to determine if there has been a "control break" in the file …more fields… 3. …more fields… 1. 4. 31
COBOL Program to do Control Break – Procedure Division – 2 of 3 5. 6. Driver Logic (from our pseudo-code) Process All Records – which includes 7. 5. Control Break Process – note the detailed logic PERFORM statements to paragraphs on the next slide 6. in the comments 7. § Note that this is actually the same program we have been working with all along in this unit, just better structured 32
COBOL Program to do Control Break – Final Paragraphs – 3 of 3 8. Process Detail Records – note the additional code to add to the Control Break hold areas 9. Initial Process paragraph – to setup the report, do the priming file read, and initialize the control break values 10. End-of-Program Process – which does the final control break, and writes out the standard end-of-job report summary lines 10. 9. § 33 Note also that we've made the Read Routine into a separately performed paragraph. This is a "best practice"
Workshop – Control Break Reports – 1 of 4 1. From the slide notes, copy all of the new data records – that contain the State code, and paste them into c: customer. In. dat – replacing the existing records 2. View the state values in the file – note that they are sorted from low to high (from California to Hawaii). 34
Workshop – Control Break Reports – 2 of 4 1. 2. 3. 4. 5. 6. 7. 8. From the slide notes, copy the program source (all of the COBOL statements) Create a new file in the chapter 4 project, in the cobol folder, named: rpt 2. cbl Paste the code in the editor Do a Local Syntax check of the program – ensure no errors Right-click over rpt 2, and Nominate as Entry Point Rebuild the chapter 4 project Expand the Build. Output folder, right-click and select Debug As > Debug Configurations Setup a new Debug Configuration as shown 9. Debug the program § § Step to understand the code flow Resume (run) to end of program 10. Look at the output file produced (probably: c: customer. Out. dat) § Unless you've changed the file Return to z/OS Project Perspective 35
Workshop – Control Break Reports – 3 of 4 – Development Specs Let's throw in some new specs for a brand new control break program that produces a listing of employee salaries by state. Using the data in the Slide Notes, create: c: employee. dat. (see screen capture) c: employee. dat § Note – these are well-paid employees. Probably hedge fund managers. 4 It will line up the with the EMPLOYEE-RECORD layout shown below 4 Using the Control Break pattern from rpt 3. cbl – create a program in the chapter 4 cobol folder that produces the Control Break report shown on the next slide 4 There are no edit errors in this file, so you can just concentrate on coding the Control Break logic pattern Break on EMPLOYEE-STATE value change c: employee. dat 36
Workshop – Control Break Reports – 4 of 4 – Development Specs The employee salary Control Break Report Optional workshop functionality includes: § § A report header With the current date And page# And edit routine for: 4 Valid numeric salary 4 A more realistic salary range for employees (who are not hedge fund managers) 37
What About Multi-Level Control Break Reports? § As common as single-level control break functionality in COBOL business applications are multi-level control break reports, that have: 4 Major key § Middle key – Minor key Or more levels of control break, and that process data in files that is sorted on the same key sequence. Consider this example of a (fictitious) grocery store report Major Key Middle Key Minor Key § Note keys of: State, City, Store# 4 And coincidentally, note that additional data control breaks would be possible (probable? ) along the lines of Store Department and SKU § At the risk of repeating ourselves, control break processing turns data into information 38
Data For a Two-Level Control Break Report § If you're going to break on two control fields, you need to columns of data, both sorted, in a Parent Child, or Master Detail sequence: 4 Sort on Parent key values 4 Within the Parent key, sort on Child key values § Note the following – in our current customer. In. dat file: 4 Master/Parent Key data: § State code 4 Detail/Child Key data: § Territory code § Find both sets of values in this screen capture Question: So if we have our data arranged by this two-level control break sequence, what elements in our program do you think we'll have to change? Answer: 4 Output report lines 4 A Parent/Master control break test and processing paragraph 4 A Child/Detail control break test and processing paragraph 4 The various hold areas, counters and accumulators coded for both Parent and Child control breaks § This will be clearer if we have a look at the output produced (next slide) 39
A Two-Level Control Break Report Note the following: Detail/Child control break line Master/Parent control break line Let's have a look at the actual COBOL code used to produce this. 40
COBOL Code For a Two-Level Control Break – 1 of 2 § We're going to reuse the rpt 2. cbl program for this example. § We will enhance it to add: 4 A Control Break output line for Territory Control Breaks 4 Hold fields for Territory values …more fields… § Note that we will have to rename the generically-named State fields …more fields… and begin Procedure Division 4 In the PROCEDURE DIVISION we see the key logic modification § Test for a Major/Parent key control break … then … § Test for a Minor/Child key control break – In that order 41
COBOL Code For a Two-Level Control Break – 2 of 2 § We will need a new Minor/Child control break processing paragraph – that will eerily resemble the Major/Parent control break process. § With a few exceptions: 4 The Parent control break will perform the child control break § Note that this could happen for any # of intermediate levels as well – following the data sort key relationships from highest to lowest sort-key § What's important is that the Perform of lower-level control breaks happen BEFORE the upper-level control breaks. 4 The Child control break will print out the Territory line – and re-initialize the counters and accumulators 42
Workshop – A Two-Level Control Break Program § Return to your single-level Control Break program. § You will use the new data records for c: employee. dat 4 They are in the Slide Notes § Enhance the program to produce the report shown on the next slide 43
Workshop – A Two-Level Control Break Program § Note the Sub-Totals and total values. 44
Unit COBOL Report Writing Patterns Topics: § Report Writing Concepts § COBOL Print and Report Layouts § Simple COBOL Reports § Control Break Reports § Appendices 45
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