progress 4gl session variables
I truly appreciate the time and work you put into sharing your knowledge. 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. I'll assume you don't own the source code. I wonder why we have to persuade you all the time, I would rather persuade PSC Based on my experience with OEA, the parser behind ProLint is better than the one PSC is using although they really aren't trying to do the same thing. - and you don't want to new up a locator object every time to locate the "Singleton"-instance in the class instance-chain? Ans:- The difference between for first and find first is: 1. ANS:- By Defining the STREAM you can send the data(output) to more than one destination at a time by single stream name. A query is a request for information from a database. The concept of sharing was originally introduced in early versions of the 4GL before parameter passing was implemented in the product. What is the difference between LIKE and AS while defining a variable? What I like about this pseudo-singleton approach is that it is usable as of 10.1A, but when we get true singletons later, one can simply collapse the action code into the finder and all the rest of the code is likely to remain the same. Shared Variable - Defines a variable that was created by another procedure that used the DEFINE NEW SHARED VARIABLE or DEFINE NEW GLOBAL SHARED VARIABLE statement. We cannot use it in where clause, doing so generates error. It would cause people with some code bases to avoid upgrading and it would break a lot of automated build processes. ProLint is wonderful but it covers a different set of problems. 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. Not the answer you're looking for? What flags you need to set for the same? The DESCENDING option sorts the records in descending order as opposed to the default ascending order. I can understand existing "shared" support remaining in the language, but adding support for shared "stuff" in new technology like PDS??? of a reverse reserved keyword kind of thing. Receipts can be processed against these purchase orders. What are the types of Indexes? Progress uses frames to ease the task of laying out your data, so that you do not have to individually position every field in widget that you want to display. If no locks are specified then it will be specified as shared lock. When you pass arguments to an external procedure, Progress converts those arguments to character format. You can also get some basic help from the compiler (assuming you . Scanning for deprecated usage is exactly the same kind of scanning for other things one doesn't want in one's code that ProLint was designed for. Q:- Can you define a variable with same name both inside and outside a procedure? 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. Making statements based on opinion; back them up with references or personal experience. What are the arguments for/against anonymous authorship of the Gospels. That does not make it a virtue to guide people toward usage which we now recognize as undesireable. Once the frame has been "realized" you cannot change its height or width. Could a subterranean river or aquifer generate enough continuous momentum to power a waterwheel for the purpose of producing electricity? Saying "never" to shared variables is similar to saying "never" to denormalised data and we all know that there are some very specific cases where we might need to denormalise. Using Comma(,) we can define more than for each statement. Progress certainly supports SQL, but the Progress 4GL and SQL are two different things. Can-do function :- Checks a string value against two types of comma-separated lists: An ID list of one or more user permission strings that indicate what users have access to the current procedure. However, it should appear somewhere in the EDITING phrase because Progress does not automatically read keystrokes when you use an EDITING phrase. Of course, that's one of the balancing points of being in the software game. A Block is a series of 4GL statements grouped together and treated as a single unit. Because they're an insidious cancer in an application's development that should be replaced by other, newer and safer methods of sharing information between procedures, rather than being touted as a plausible option for an unwitting developer to use. Can we define the same NEW SHARED variable in Multiple Procedures? But how are you going to find this singleton object when: - there is no "static" specifier in the OO4GL (there is no "METHOD PUBLIC STATIC " nor a "STATIC CLASS " as far as I know). I'm repeating myself). Why don't we use the 7805 for car phone chargers? Otherwise, it is the directory specified using the Temporary Directory (-T) parameter. For Starship, using B9 and later, how will separation work if the Hydrualic Power Units are no longer needed for the TVC System? The scope is untill the execution of the program where it is defined ends. Q:- Progress supports how many types of variable? In this scenario the extra time taken for the ambiguousness test may take a few milliseconds, however, if the FIND statement is inside a block that is executed many thousand (or hundreds of thousands of times) the cumulative effect of those 'few milliseconds' will quickly add up and may well be the root cause of what is perceived to be a poorly performing query. Folder's list view has different sized fonts in different folders. What will be the lock when we read the record and update the record? I agree with you that it is an important goal, but I also recognize that it is not an easy one. In set it directly update the data from record buffer to database. DEFINE VARIABLE a AS CHARACTER EXTENT 5 NO-UNDO. Oh, you mean like all of the OERA code examples? I'm skimming John Sadd's OE 4GL handlebook "expert series" (http://www.psdn.com/library/entry.jspa?categoryID=239&externalID=474) and came across this reference on page 14-24: The traditional Progress programming technique of using SHARED variables. Purchase orders contain a single delivery date for each line item. Reactions:trmrahim Defines or forward declares a user-defined function. This, to me, is one of the very interesting challenges facing PSC. Logical gets two values yes / no or true / false initial value No. In fact, unfortunate as it may be, most Progress users have never even heard of it. Non-Persistant procedures will store the values to the variables only till the procedure is executing. //A date variable set to todays date. Not the answer you're looking for? If u define the temp table then first we update the data into temp table then from temp table with one shot we can update all changes to database directly, mean while at the time of temp table updation, other user can use the same table, means we have reduces the network traffic and reduces hitting of db table. Ans:- Progress provides you with one buffer for each table that you use in a procedure. SYNTAX -- LOOKUP ( expression , list [ , character ] ). Why does progress use frames? with public data members! It's a nice check off on the marketing side though. Will look for the string "shared var" in any case in all *.p files. Which was the first Sci-Fi story to predict obnoxious "robo calls"? rev2023.5.1.43405. //An character array with length = 5, DEFINE VARIABLE j AS INTEGER EXTENT NO-UNDO. MESSAGE VALID-HANDLE(whand) VIEW-AS ALERT-BOX INFORMATION BUTTONS OK. Content Discovery initiative April 13 update: Related questions using a Review our technical responses for the 2023 Developer Survey, Openedge 11 Microsoft SQL Server Dataserver performance, Properly implementing auto-incrementing primary keys in OpenEdge 10.2B using SQL / JDBC, MQ C function (shared library / .dll) binding causing hard crash on zmq_init. Session triggers are defined as part of a particular application and are only in effect for that particular application. The third line will procude the following error: You can use the INITIAL option on the DEFINE VARIABLE statement to set initial values. Can I use an 11 watt LED bulb in a lamp rated for 8.6 watts maximum? If you do not use the BY option, PRESELECT sorts the records in order by the index used to extract the records. Procedures can use shared variables and other mechanisms to share data between. A minor scale definition: am I missing something? Using code similar to the following: DEFINE VARIABLE v-cha-usr-tempdir AS CHARACTER NO-UNDO. there is an entire sub-section earlier in the book. It's true that certain vendors got (very) carried away with them 20 years ago and set some horrible examples that live on to this day inspiring bad programmers to be even worse but doesn't mean that they should be reviled in quite the same way that USE-INDEX and CAN-DO deserve to be. u can check this by using the ETIME() Function to check the time taken by these two. Strong Scoped Reference if the buffer is strong scoped then you cannot reference that buffer in a containing block .The buffer is always scoped to the strong scope block. disadvantages weren't sufficiently emphasized. Define Input Parameter, Output Parameter and Input-Output Parameter? When you write a record to the database, Progress gets that record from the record buffer. Another factor is that a set of best practice standards is not well established and universally agreed upon. And, clearly they should be provided with guidance. Share-Lock(default lock, other user can read but not update), Exclusive-lock (other cannot read and update). 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. What is Wario dropping at the end of Super Mario Land 2 and why? Defines and identifies a variable to be shared by a procedure called directly or indirectly by the current procedure. 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. Stores the identifier for the records stored in the database. The calling procedures temp table and the called procedures temp table need not have matching indexes. Progress recompiles the called procedure, substitutes arguments, and then runs the procedure. A shared variable defined in parent program can be used in all its sub programs but the vice versa is not possible. . All relevant tables associated with the online maintenance are updated correctly. The default buffers in progress are Data Buffer, Record buffer, Screen Buffer, Edit Buffer which are mainly used for input output operation. The variable which can be used by the entire mfg pro once you successfully login to the editor is called the globally shared variable. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, +1 because I didn't define my requirements well enough, and for all I know this might work when staying strictly within the AVM. It is good news, and I was going to mention it - but you beat me to it. Some people report, it as a critical bug even if we didn't intend to do. PSC has certainly done that with some language elements which were (and are) in wide use and I see no reason why shared shouldn't be added to that list. In other environments you can tell the compiler to suppress certain warnings. One is that a lot of the documentation was written a long time ago when awareness of some best practice standards was not nearly as widely understood as it is today not that they are universally understood even now. By using the temp table we can reduce the network traffic on server to DB. A transaction is a set of changes to the database, which the system either completes or discards, leaving no modification to the database. What are the different types of purchase order available in Mfg/Pro? Of course, that's one of the balancing points of, being in the software game. 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). 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. What i need to do is set the variable to create the date range, search and display the results of every sales order of the defined month and year. But, this doesn't seem to be making it out in to the examples. I know that PSC feels it necessary to "comfort" people who are used to procedural code that it is still a valid paradigm, but that doesn't mean that every verb or modifier needs to be called good. Progress ABL is statically typed. It is important to continue to support existing code, at least for a significant period. What are the different types of data types available in progress? If you invoke the ENABLE statement for a frame, Progress brings the frame into view unless the HIDDEN attribute for the frame or one of its ancestor frames or windows is TRUE. //A variable with a label. The solution that's been, in my head for awhile is to let users indicate what, things in the syntax they don't want to support, sort. What is an Recid ? For instance, DEFINE [NEW ] DATASET and the like? If an application with several procedures defines a NEW SHARED variable with the same name in each procedure, Progress creates a different instance of the NEW SHARED variable in each procedure. So I would say that shared variables were discussed in the book "for historical reference", and if their disadvantages weren't sufficiently emphasized, well, shoot me, but we are doing our best to move the community forward while at least acknowledging that newer better programming mechanisms co-exist (happily, for the most part) with older code that remains successful for what it does and will continue to do so. . That states that no undo handling is wanted for this specific variable in case of a transactional roll-back. Progress, Telerik, Ipswitch and certain product names used herein are trademarks or registered trademarks of Progress Software Corporation and/or one of its subsidiaries or affiliates in the U.S. and/or other countries. There are a number of places in the book where I try to describe outdated features, while leaving it to others in the company to make formal definitions of what is "deprecated" and what that really means. We use the temp table in client server architecture. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. What it will be when updated and during other times? Then one gets the warning when one is ready to do something about it. Transaction warnings are pretty common and you don't "have" to fix them any more than you "have" to fix a shared variable. DEFINE VARIABLE dt AS DATE INTIAL TODAY NO-UNDO. Not only does that provide the programmer new to this area with guidance in the right usage pattern, but it will help to educate him or her on how he or she might rework older code. What is the definition of shared variable? "Traditional" ways of doing things need to be replaced when better ways of doing things come along. define variable s_date as character format "99/9999" no-undo. If you do not specify the UNDO option, then the current transaction is committed when the QUIT statement is executed. 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. What is the difference between Variable, Parameter, and Argument? If you need to share buffers among procedures, use the DEFINE SHARED BUFFER statement. For first can use multiple indexes and Find cab use only one index. Where does the version of Hamapil that is different from the Gemara come from? For first statement displays the first value of the record that matches the condition based on the index key. Yes, there are. What is deadlock? As Niel indicated and as you no doubt appreciate, it is always difficult to strike the right balance between supporting the existing base and encouraging the adoption of new features. database. Record buffer:- A temporary storage area in data memory for a record, field, or variable. And remember to get fill-ins side-label-handle to move them too, otherwise the fill-in itself moves, but the text stays. When you read a record from the database, Progress makes it available to your application in the record buffer. I'm not saying that instruction of historical language element usages should be eliminated. whand = HANDLE(chand). If some nags were to (finally) be inserted in OE10 we might begin to see some general recognition that, oh say shared variables, are a bad idea by the time version 13 rolls out. Weak Scoped Reference - if you have weak scope referenced buffer, you can reference that same buffer outside the weak scoped block. What is an Include file? I'm not running any ABL code at all, it's all Ruby and Java (using JRuby; a Ruby interpreter running on the JVM). The mis-use is what makes them evil, not their existence. You have no argument that it is not a silver bullet. folks out there who think they are perfectly OK after all, it is a "traditional Progress programming. 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).