The value of a global shared variable remains available throughout a Progress session. What is deadlock? If the null hypothesis is never really true, is there a point to using a statistical test without a priori power analysis? It is depending on the logic build in the include file. Exclusive lock is used to update modify or delete the datas of the table. If a table is exclusive locked then other users cannot update that table but can view it using No-LOCK. The "Evil-ness" of something isn't necessarily about their existence, but how they're used or are abused in order to (wrongly) accomplish a particular goal. What are the different types of blocks available in progress? INPUT-OUTPUT parameter data moves from the calling procedure to the called procedure, then back to the calling procedure. No, only external Procedures will create .r file during execution and can have more than one Internal Procedures. We use the temp table in client server architecture. If you don't want to be bothered by the list then you can simply delete it. Tests a character expression to see if that expression begins with a second character expression. What is the difference between Prompt-For statement and Set Statement? //A date variable set to todays date. Asking for help, clarification, or responding to other answers. Mfhead.i to display the header in the report containing page nos and date. This is a functionality provided by Progress to upload data into the tables with proper validations. If you use BREAK, you must also use BY. The maximum size is 28000. In above example if u doesnt mention the NO-WAIT clause and mean while if user1 has gone for some other work/tea, then user2 will hit the database every time to update the record, means progress will not move the next line of code until it will not get the release of exclusive-lock. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. I'm repeating myself). progress-4gl Tutorial => Basic variable declarations The update statement let you make changes to the record and progress upgrades the shared-lock to an Exclusive Lock. 2. Defines and identifies a variable that was created by another procedure that used the DEFINE NEW SHARED VARIABLE or DEFINE NEW GLOBAL SHARED VARIABLE statement. Yes, and one can make a good case that static variables are also evil and are bad OO. What is the difference between Temp-Table and Work-Table? Defines and identifies a variable to be shared by a procedure called directly or indirectly by the current procedure. How to determine if a shared variable has been defined NEW? Other methods (like "choose") have been deprecated by PSC, but nothing's been suggested to replace it. For example, a reference to {{1}} in an include file causes Progress to include the statements from the file with the name that passed as the first argument. Users should be encouraged to move to more recent, better ways of doing things rather than perpetuating older, obsolete techniques. Quantities and due dates can be entered up to the time when a blanket order becomes a purchase order. You normalize a database in order to ensure data consistency and stability, to minimize data redundancy, and to ensure consistent update and maintainability of the data, and avoid update and delete anomalies that result in ambiguous data or inconsistent results. I'm always a fan of showing more options and explaining why one would make choices, but the specific example this thread started with is definitely a best practices issue well, or a worst practices issue. In the PSDN materials in the OE Practices area, we are trying to establish firmer guidelines for "modern" programming in ABL, which of course will include (any day now, we promise, Thomas) material and examples on class-based programming and other features of OE10.1 and more releases to come. What are types of locks? ANS:- By Defining the STREAM you can send the data(output) to more than one destination at a time by single stream name. In other environments you can tell the compiler to suppress certain warnings. What is Schedule order and explain its Process cycle? If an error is encountered during the execution of the loop, it will help to come out of the loop by setting Batchrun parameter to Yes. define variable s_date as character format "99/9999" no-undo. Over and over and over again I see, Actuate developers define global variables in order to pass some, information from one context to another when it is quite possible, to pass this info in a good OO way by having the objects, interrogate their context. Thanks for contributing an answer to Stack Overflow! rev2023.5.1.43405. Searches the directories and libraries defined in the PROPATH environment variable for a file. For is a progress block and find is a progress statement. Unfortunately, due to the lack of support, I've had to impose restrictions on the client to provide either one of the above (and lacking either, the code assumes a sequence of _id_seq exists). Define new shared variable variable name during the first time the variable is defined in the main program. I personally don't get hung up and worry about "best practice" - there's lots different ways to skin a cat, depending on the variations of what a coder's trying to accomplish, personal quirks, etc. The variables need to be declared and the datatype cannot be changed during run time. But I would just like to mention a few things: 1) We are listening. In above example same time if other user also want to update the same record then other user will not have to wait to release the lock, user2 (progress) will find the no-wait clause and it will go for else part or next line of code. A preprocessor directive is a statement that begins with an ampersand and is meaningful only to the preprocessor. I know I didn't read the entire book, and I have no intention of doing so since I was only looking for specific material I need to figure out. I can go with that a few releases, but sooner or later the docs need to be. New shared Variable - Defines a variable to be shared by a procedure called directly or indirectly by the current procedure. */ /* Strings. The concept of sharing was originally introduced in early versions of the 4GL before parameter passing was implemented in the product. Assign moves the data from screen buffer to record buffer. C# example: Any code that uses "person.GetName()" will get a compiler warning "Use Name instead". Of course, that's one of the balancing points of, being in the software game. Now that parameters can be passed, the need for SV's no longer exists in new code. That does not make it a virtue to guide people toward usage which we now recognize as undesireable. If you do not want, or if you do not need, the value of a variable to be undone even when it has been changed during a transaction, use the NO-UNDO option with the DEFINE VARIABLE statement. Procedure can be ab external procedure(.p,.w) but not function. Notice the inclusion of a trigger overrides whatever was there before (since your window did not resize, I don't think it will harm it. What is that something else that is better? There is a start_date column in my db (format "99/99/9999"(dd/mm/yyyy)) the date when a customer sales order was entered. Syntax DEFINE VARIABLE i AS INT64 INITIAL -200 NO-UNDO. What are the different types of Blocks? It can be done by defining the variable as the shared variable. Perhaps there should even be a section in the docs on "practices to be avoided", BTW -- I do agree that the documentation should be, done differently. It allows you to retrieve a pointer to a fetched record. Define Input Parameter, Output Parameter and Input-Output Parameter? You can use the name of an include file as an argument to another include file. 5. Canadian of Polish descent travel to Poland with Canadian passport. All relevant tables associated with the online maintenance are updated correctly. It's a nice check off on the marketing side though. Why, in the docs used to describe cutting-edge ABL technology, is shared variables mentioned front-and center, when it should be relegated to "other mechanisms"? .lg (time of database up and shut down). Get monthly updates about new articles, cheatsheets, and tricks. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. As it is certain features that are prone to mis-use (such as shared variables, CAN-DO and USE-INDEX) are far too prominently featured in the documentation and, in many cases, are held up as exemplars when they should not be. If time does not permit, one doesn't need the compile nagging 20 times when doing 20 compiles. How about using PUBLISH and SUBSCRIBE? Please give a brief about no-undo and undo option. Progress ABL is a strongly typed, late-bound, English-like programming language with growing support for object orientation. Do any of these relate to a domain where one would be writing ABL code of any form? PROGRESS gives you the ability to deploy your applications across a wide range of platforms and configurations -- host-based and client/server environments, open and proprietary systems, and character and graphical interfaces -- without changing the application logic. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. This yields more efficient code.). Yes, there are. INPUT-OUTPUT PARAMETER - Defines a parameter that receives an initial value passed from the calling procedure that can be subsequently modified by the called procedure. Consider, though, that these reference books may or may not be read "in context" as you appear to be defining it. In my own defense, if this is necessary, there is an entire sub-section earlier in the book entitled "Why you generally shouldn't use shared variables", which tries to balance the "traditional" (if you'll pardon the expression) use of shared variables and more modern ABL programming techniques. Q:- Progress supports how many types of variable? Means same time other user can not use that db table. If we had a video livestream of a clock being sent to Mars, what would we see? If it does then those processes deserve to break. It will be set as shared lock during other times. Progress automatically supplies looping services to REPEAT and FOR EACH blocks. And you think we, hear it about continuing old conventions, you should, hear what happens when we don't! In transaction we maintain the data integrity at database level. 3) It would be very nice if the warning message itself were in the file and could be edited. People are just lazy about learning how. What will it return if expression is not in the list? NO-UNDO variables are efficient; use this option whenever possible. Ans:- 1. find is a statement and can-find is a function. A shared variable defined in parent program can be used in all its sub programs but the vice versa is not possible. Is "I didn't think it was serious" usually a good defence against "duty to rescue"? When you write a record to the database, Progress gets that record from the record buffer. It is important to continue to support existing code, at least for a significant period. Two MacBook Pro with same model number (A1286) but different year, Passing negative parameters to a wolframscript. Nor is the idea that compilers, in general, should do so. For is a progress block and find is a progress statement. Progress 4GL - Define variable month/year Ask Question Asked 7 years, 10 months ago Modified 7 years, 10 months ago Viewed 2k times 1 Here's the problem, i need to create a date range on the variable below. Progress contains an environment variable called PROPATH which contains a list of directories that progress searches to find procedures. Oracle 11g SQL - DD/MON/YYYY to MONTH DD, YYYY with WHERE month year clause, How to Extract Year from DATE in POSTGRESQL, Hello how can i joint table in progress 4gl? Shared variables had their uses when procedures didn't allow for passing parameters. Ans:- Progress provides you with one buffer for each table that you use in a procedure. While find first it is possible to specify the break by condition and sort the records and it will display the first record based on the sorting. of a reverse reserved keyword kind of thing. Get monthly updates about new articles, cheatsheets, and tricks. 4GL/ABL: How to set the PROPATH environment variable for an AppServer When I pass Temp table as parameters, what are the rules apply to Temp table parameters? Indicates that the specified block is undone. How are engines numbered on Starship and Super Heavy? Sorts the pre-selected records by the value of expression. /* These variables are declared with `NO-UNDO`. The compiler should be silent unless there is something fatal or a good reason to expect that the code will not perform as intended (like moving colon position). By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. A constant, field name, variable name, or expression that you want to pass as a compile-time argument to the external procedure you are running. So best programming practice is that whenever use the exclusive-lock also use the no-wait. A transaction is a set of changes to the database, which the system either completes or discards, leaving no modification to the database. Did I not indicate that it is very possible to write bad OO code? This Solution describes how to pass parameters to Progress from the command line to a 4GL program. Would My Planets Blue Sun Kill Earth-Life? Progress uses that buffer to store one record at a time from the table as the records are needed during the procedure. The documentation (http://www.psdn.com/library/entry.jspa?externalID=437&categoryID=261) by the way states: You cannot define a NEW SHARED or NEW GLOBAL SHARED variable in a class. 3. Do you have benchmarks to prove that they have measurable performance advantages? Good practice should be emphasized, and less good practice relegated to the "notes", section or at least given less prominent billing. INPUT PARAMETER - Defines a parameter that gets its value from one of the following sources: If the calling procedure runs the current (called) procedure synchronously, the value comes from the corresponding INPUT parameter of the RUN statement. What are the types of frames? What does 'They're at four. What were the most popular text editors for MS-DOS in the 1980s? It gets used when one is ready, willing, and able to fix things that are undesireable without getting in the way of day to day development. It can be done using the extent statement during the variable declaration. How do you find the end of its results list? Or, you can put the value in an SP or singleton. JavaScript is disabled. I find it very difficult to believe that the overhead of the run itself doesn't swamp out the overhead associated with a parameter versus a shared variable. My point is that we have a perfectly good tool, ProLint to do this kind of warning. You can make this much better and more efficient with any regexp describing exactly what you want to look for. Q:- What is the diff between find and can-find? Certainly not "traditional." Has the Melford Hall manuscript poem "Whoso terms love a fire" been attributed to any poetDonne, Roe, or other? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, Progress 4GL - Define variable month/year, How a top-ranked engineering school reimagined CS curriculum (Ep. New Global Shared Variable - Defines a variable that can be used by any procedure that names that variable using the DEFINE SHARED VARIABLE statement. The Handbook is intended as an extended language tutorial, not a best practices or application design guide. Progress automatically puts a SHARE-LOCK on a record when it is read and automatically puts an EXCLUSIVE-LOCK on a record when it is updated. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Of course, couldn't one simply put the despised keywords into the forget list and get error messages now? You can mark your own methods as "obsolete" which either results in a compiler warning or error. Please start with the problem, not the proposed solution. How a top-ranked engineering school reimagined CS curriculum (Ep. Thank you very much for sharing. 2. DEFINE VARIABLE dt AS DATE INTIAL TODAY NO-UNDO. Specifying NO-UNDO for a variable is useful if you want to indicate an error condition as the value of the variable, perform an UNDO, and later take some action based on that error condition. You also might want to set session:suppress-warnings to YES before you get this running, because every time a widget doesn't fit the frame, OpenEdge will let you know about it. For what domains is it better? Parameter:- U can pass the parameter at run time. The underlying use case for my question was for a way of implementing auto-incrementing primary keys on INSERTs that would communicate back to the client the inserted ID, so that I would not have to force the client to either. for first displays data without sorting while find first display data after sorting,So the for first is more efficient in terms of time taken for displaying the record as compared to find first. I imagine if your code is previous to v8, you might be out of luck. ENABLE Enables input for one or more field-level and child frame widgets within a frame. How do I use PHP to get the current year? If there existed a SQL function that would return a special session ID that corresponded to the client's transient connection to the SQL engine, it would be possible to have the client and trigger/stored procedure communicate using a pre-determined table as a request queue (by using the session ID as a key). As n vn u want recurring = exact qty. . OO has a place but it isn't the be all and end all. I think that Sal is proposing a reasonable compromise. All character fields should be enclosed in quotes (). This behavior supports recursive procedures and bill-of-materials applications. Function will return single value to the caller. It's not them. JavaScript is disabled. How will you declare the variable that is to be used in more than one programs? :-). There is no separate definition for shared lock. So anyway I'm guessing that yes, your code should work for ABL clients accessing the DB through the ABL engine, however isn't feasible for clients that only access OE through the SQL engine (which uses Java stored procedures for triggers that are entirely separate from ABL triggers). Content Discovery initiative April 13 update: Related questions using a Review our technical responses for the 2023 Developer Survey, how to replace all the email id records with progress 4gl, Progress 4gl, Openedge Update Progress.ini in all users, Progress 4GL: How to find where a procedure is defined. [ PRIVATE | PROTECTED | PUBLIC ] VARIABLE variable-name. However, it should appear somewhere in the EDITING phrase because Progress does not automatically read keystrokes when you use an EDITING phrase. Procedures can use shared variables and other mechanisms to share data between. But, there also should be good guidance in best practices with new features (and what not to use in old features). IMHO Progress 4GL is fairly weak in this regard -- it doesn't warn about lots of things that it ought to warn about and that just encourages a lot of bad practices. A query can involve one or more tables and can consist related records from FOR EACH Statement. But in a broader sense, isn't it a good thing Progress is a multi-paradigm language ? I've an old desktop application developed in progress 4gl.There is a frame contained in a progress window now my task is to make the frame responsive ie based on the size of its container window the frame should resize dynamically.Is it possible in Progress any workaround will be appreciated.Thanks openedge progress-4gl Share Improve this question But doing that for a widget that already has an event procedure will cause it to stop doing what it currently does (unless you can code it, but again I don't think you have the code). 6. What is preprocessor directive? Myself, I think having the compiler throw non-fatal warnings would be a bad idea. It will be upgraded to Exclusive lock when data is updated. By using the temp table we can reduce the network traffic on server to DB. And, clearly they should be provided with guidance on how to make old code and new code work together, something which I think is a bit weak in the current documentation. DEFINE VARIABLE . For example, the installation automatically sets the %DLC% environment variable to your OpenEdge installation path. That policy has its cost, of course, and I'm not sure that it has entirely fulfilled its purpose, as witness the large number of sites (vast majority?) The underlying record buffer of a field or variable is unaffected. 1) There should be a default list that contains all keywords which PSC has deprecated (EDITING, PUT SCREEN etc). A character longer than 32K should be a longchar */ DEFINE . This acts the same way the data entered manually with all the validations put in the program. But the default should be "full nagging". Boy, you step out of the room for a minute (well, to, Greece and back and various other places) and all. Why don't we use the 7805 for car phone chargers? qty can be ieregular. another way to pass parameters to a Progress 4GL procedure is passing the parameters with the -param option. Include file can be compiled in case of the code built inside can execute independently. u can check this by using the ETIME() Function to check the time taken by these two. /* A handle is a handle to anything: a session, an on screen widget etc */ /* A Com-handle is used for ActiveX Com-automation */ DEFINE VARIABLE h AS HANDLE NO-UNDO. If you need more than one record at a time from a table, you can use the DEFINE BUFFER statement to define additional buffers for that table. What's the cheapest way to buy out a sibling's share of our parents house if I have no cash and want to pay less than the appraised value? Application design is part of language instruction, since the how one uses the language implies some sort of inherent application design. Screen Buffer A display area for a field, variable or the result of a calculation. Stackoverflow tagged OpenEdge or Progress-4GL/DB, Occasionally encounter error 5890 and 5884 with excel com-object, [Stackoverflow] [Progress OpenEdge ABL] Sometimes having error with CSV output file from 4GL program, [Stackoverflow] [Progress OpenEdge ABL] How to use the OpenEdge debugger (OpenEdge Debugger 11.6). What is the definition of shared variable? The use-index option of the record phrase allows you to choose the defined index by which you want to access the selected records. Updated Apr 12, 2017 By default, the OpenEdge installation program tailors all the necessary OpenEdge and Java environment variables to the directories where they are installed. DEFINE VARIABLE i AS INT64 INITIAL -200 NO-UNDO. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. In update statement it will display the previous value on screen buffer and ask to user to overwrite the new value which is to be updated, means data will move to from screen buffer to record buffer to database. The scope of the record is the nearest enclosing block that encompasses all the references to the record. progress-4gl Tutorial => Variables I truly appreciate the time and work you put into sharing your knowledge. Since find does not support by, use index comes in handy to sort the records and it makes clear to which of the defined indexes to use for the sort order. Sends the value of one or more expressions to an output destination other than the terminal. It allows you to modularize your code and reduce the number of external files in an application. It would cause people, with some code bases to avoid upgrading and it would, break a lot of automated build processes. That might lessen the need to fix all the old stuff. Well, yes but I think that Tim's point is that one should be giving a consistent message. //An extent without a set length, DEFINE VARIABLE b AS DATETIME LABEL "Departure time".
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