I am developing a netlogo extension and I want to add a command where the user will tell me a list of procedures names that have no parameters.
Later I will perform this procedures but the only thing I will know is the name of the procedure that was passed to me before.
The command that the user will use to inform the name of the procedures is the following:
qlearningextension:actions ["procedure1" "procedure2" "procedure3"]
Later the extension will perform this procedures. I want to know if there is a way to get a procedure with only having it's name.
My recommendation would be to change the syntax of your primitive from taking in a list of strings to taking in a repeatable number of anonymous commands. You can do this by setting the syntax to CommandType | RepeatableType. A good reference should be the ControlFlow extension (cf) which uses a similar technique to accept at least 1, but possibly many, boolean/command combinations for its variadic cf:iflese primitive.
The anonymous commands provided will be checked for correctness at compile time, meaning you won't have to rely on the extension user properly typing the name of the procedures or forgetting if they change a name. The commands will also be easily executable by your extension prim at runtime, you won't have to "search" for the right procedure to execute (again, see the cf example).
Users of your extension will need to wrap your prim in parens when using the "more than 1" repeatable syntax: (qlearningextension:actions [procedure1] [procedure2] [procedure3])
Related
In a green screen session, caling a program MYLIB/TESTPRG works when my library list is set to QGPL, QTEMP, VENDRLIB1, VENDRLIB2, VENDRLIB3. I can execute call MYLIB/TESTPRG on a green screen command line.
I want to be able to run this command from my Windows client. I created an external stored procedure MYLIB/TESTPROC with external name MYLIB/TESTPRG as I have seen in various articles. My original question stated that I could execute this procedure successfully in STRSQL in a green screen session with my library list as above, but that is false. It does not work. It simply says 'Trigger program or external routine detected an error.' Sorry for the wrong information.
When MYLIB/TESTPROC is called from the client (CALL MYLIB/TESTPROC), it fails with CPF9810 (Library &1 not found). I connected to the database via i Navigator -> Run SQL Scripts. In Connection -> JDBC Settings I had Default SQL schema = 'Use library list of server job' and set Schema list=QGPL,QTEMP,VENDRLIB1,VENDRLIB2,VENDRLIB3. I then executed CALL MYLIB/TESTPROC and got the message as stated above.
What works is when I run the program, i.e. CALL MYLIB/TESTPRG on a green screen command line.
TESTPRG is a C program that takes no arguments. The stored procedure was defined like this:
CREATE PROCEDURE MYLIB/TESTPROC
LANGUAGE C
SPECIFIC MYLIB/TESTPROC
NOT DETERMINISTIC
NO SQL
CALLED ON NULL INPUT
EXTERNAL NAME 'MYLIB/TESTPRG'
PARAMETER STYLE GENERAL ;
CPF9810 - Library &1 not found means that something is trying to access Library &1 (whatever that is, you didn't tell us) and the library as typed is not on the system anywhere. &1 is not the name of the library, it is a substitution variable which will display the library name in the job log. Look at the real library spelling in the job log. Check your spelling. Check the connection to make sure all the libraries are specified correctly. The message will tell you exactly which library is causing the problem.
If indeed the program works in green screen when the library list is set properly, then I would expect the problem to be in your connection where it is trying to set a library list. You cannot add a non-existent library to the library list. That is why it works in green screen, your library is necessarily typed correctly there, or it wouldn't be in the library list. You would get a similar error (same text, different error code) if you tried to add library with a spelling error to the library list in green screen.
Figure out the full text of the message (look in the job log), and you will see just what is throwing the error, and what the library is. Hint, it is not likely SQL throwing the error as those errors all look like SQL#### or SQ#####. More likely a CL command or it's processing program being called by an IBM server that is sending a CPF message.
As you have discovered, you can directly call simple programs without defining an external SQL procedure based on this documentation from IBM:
https://www.ibm.com/support/knowledgecenter/en/ssw_ibm_i_73/db2/rbafzcallsta.htm
I believe the recommendation to create your own external procedure definition for simple programs is primarily to reduce ambiguity. If you have programs and procedures that happen to have matching names, you need to know the rules list to figure out which one is being called for instance.
Also, the rules for external functions are different than external stored procedures and those get confused as well.
Per my comment, I usually make my procedure calls with the library within the call command.
In a terminal session using CALL PGM(MYLIB/TESTPROC). Or in a SQL session using CALL MYLIB.TESTPROC.
This can prevent someone from inadvertently putting your procedure in a personal library or the like. I usually do not specify a session library list on my SQL clients, accepting the system library list.
I had promised to accept Douglas Korinke's comment as an answer. However, I was experimenting a lot and I am no longer sure of what I knew and when I knew it. My problem had something to do with parameter passing to the C program. If I can reproduce it with a simple case I will ask another question.
In a Java program it is possible to set the libraries by using the following method :
ds.setLibraries("list of libraries");
Example :
ds.setServerName("server1");
ds.setPortNumber(1780);
ds.setDatabaseName("DBTEST");
ds.setLibraries("*LIBL,DAT452BS,DAT452BP");
I have followed other examples on stack exchange to call a built-in program from a stored procedure, but continue to get an error.
Working off this example (Looking for a working example of any OS/400 API wrapped in an external SQL stored procedure wrapped in a user defined SQL function) I built the following to attempt to create a wrapper command to allow me to change object security (my issue is that objects I create, regardless of library) are not always accessible to others in my some function, I must manually set to a common security group.
CREATE OR REPLACE PROCEDURE XX.TST( IN XOBJ CHAR(32), IN XOBJTYPE CHAR(10), IN XNEWOWN CHAR(10))
LANGUAGE CL
SPECIFIC XX.TST
NOT DETERMINISTIC
NO SQL
CALLED ON NULL INPUT
EXTERNAL NAME 'QSYS/CHGOBJOWN'
PARAMETER STYLE GENERAL;
CALL XX . TST('XX/TBL1','*FILE','GRPFRIENDS');
I get the following error:
External program CHGOBJOWN in QSYS not found
But have confirmed that going to the CL of the terminal emulator and typing QSYS/CHGOBJOWN takes me into the parameter input screen
You are trying to define a command as a program, and that just won't work. A command object (*CMD) and a program object (*PGM) are two different things, and cannot be invoked the same way. All is not lost though. There is a DB2 service that allows you to execute commands. You just have to build the proper command string.
Instead of defining a stored procedure, you can call the existing DB2 service like this:
call qsys2.qcmdexec('CHGOBJOWN OBJ(XX/TBL1) OBJTYPE(*FILE) NEWOWN(GRPFRIENDS)');
There are a whole list of services. Documentation can be found here.
This blog post shows an example of how to create a immutable_concat function in Pg:
CREATE OR REPLACE FUNCTION immutable_concat(VARIADIC "any")
RETURNS text AS 'text_concat'
LANGUAGE internal IMMUTABLE
I'd like to do the same with concat_ws and the corresponding text_concat_ws does exist, however, the following just crashes the process:
CREATE OR REPLACE FUNCTION immutable_concat_ws(VARIADIC "any")
RETURNS text AS 'text_concat_ws'
LANGUAGE internal IMMUTABLE
Update: The siguature of immutable_concat_ws should be (glue, *parts), one glue (text or varchar) and one or more parts (text, varchar or null).
What am I missing here?
Firstly, the function requires two parameters in the definition, like Richard already suggested, and you updated your question accordingly.
Secondly, you can create that function with "any" input using LANGUAGE internal. Does not mean that you should, though.
concat_ws() is only STABLE for a reason. Among others, the text representation of date or timestamp depends on locale / datestyle settings, so the result is not immutable. Indexes building on this could silently break. Restricted to text input, it's safe to declare it IMMUTABLE.
Since you only need text input (or varchar, which has an implicit cast to text), limit it to your use case and be safe:
CREATE OR REPLACE FUNCTION immutable_concat_ws(text, VARIADIC text[])
RETURNS text
LANGUAGE internal IMMUTABLE PARALLEL SAFE AS
'text_concat_ws';
Crating a LANGUAGE internal function requires superuser privileges. If that's not an option, the next best thing would be an SQL function like:
PostgreSQL full text search on many columns
Mark it as PARALLEL SAFE in Postgres 9.6 or later (it qualifies!) to enable parallelism when involving this function. The manual:
all user-defined functions are assumed to be parallel unsafe unless otherwise marked.
Resist the temptation to do things like this immutable_concat_ws('|', now()::text, 'foo'). This would reintroduce said dependencies in the call.
Related:
Combine two columns and add into one new column
OK, so you're mapping to internal "C" functions, which I must admit I've never done myself.
However, text_concat_ws is "with separator" so it doesn't just take a variadic list of text arguments - it takes a separator THEN the variadic list of text arguments. Adjust your function definition accordingly.
If you're going to be doing this, you probably want to hook a debugger up to the backend or run it single process if that's practical.
Also - I just found the doxygen interface to the PostgreSQL source-code replying to your question. Thanks :-)
PostgreSQL 9.2 has native JSON support. I'd like to store human readable config files, however, in YAML. And I think I'd like to index a few (but not all) of the config file values. Therefore I'm wondering:
Is it's somehow possible to include [a third party Javascript library that parses Yaml] in Postgres, for example js-yaml. Then I could have my own YAML Javascript helper, in the same way as there's the built-in JSON helper in PostgreSQL 9.2.
Alternatively:
is it possible to declare individual reusable Javascript functions? If so, then I could add my own YAML parsing functions (based on simple regexps), that are able to parse a subset of YAML, for example the top level key-value pairs here:
# some "top level key-value paris":
the_key: 'the value'
another_key: 'another value'
# But this however:
would_be_too_complicated_to_parse_manually_with_regexps: |
block string
with newlines
Worst case scenario would be that I'd need to duplicate YAML parsing code in each PostgreSQL stored procedure (if I cannot add 3rd party libraries or declare reusable functions).
(Performance wouldn't be terribly important in my case.)
(I've googled a while for "postgresql plv8 reusable function" and "postgresql plv8 library" but found nothing of relevance)
The pl/v8 procedural language is probably the way to go. It's a 'trusted' language, which means (among other things) it does not provide any way to do the 'load an external module from this file' thing. But it does have a 'find_function()' method to let you define your own javascript function and call it from another function (js or not). See description of it in this blog post:
http://umitanuki.hatenablog.com/entry/2012/04/10/171935
Am working in Progress 4gl and am an novice programmer. I am working on a situation where there are five procedures (.p files) which are not related to each other, sharing a single procedure (.p file).
My issue is that i need to modify the shared procedure , that should have its effect on only one calling procedure and not the other four. What are the ways that i can link these two procedures at the same time preventing the effects on other four procedures.
Pls , help me with this issue. And sorry if am not clear
The simple, but architecturally repugnant, solution is to use a global shared variable.
Many people will tell you that this is a bad coding technique. They are right. But you aren't asking for advice on best practices.
Simply create such a variable in both the caller and the callee. Procedures that don't need it won't miss it.
One of your "normal" programs:
/* p1.p */
message "p1, I'm normal.".
run common.p.
Your "special" program:
/* p2.p */
define new global shared variable special as character no-undo.
message "p2, I'm special!".
run common.p.
message "special = " special.
The common program:
/* common.p */
define new global shared variable special as character no-undo.
message "common stuff...".
if program-name(2) = "p2.p" then special = "special value".
return.
You can define a NEW GLOBAL SHARED variable as many times as you like and you only get one copy of it. The "new" doesn't overwrite any existing variables (if you leave out GLOBAL it behaves differently).
You didn't ask for it and maybe you don't need it but the program-name(2) check peeks at the call stack to see if common.p was called by p2.p.
There are other, more complicated ways to do this but they all boil down to the same problem -- you're creating the basis for some very ugly coupling between your "special" program and the now no longer generic "common" program.
The best way is to add a "flag" to the shared procedure, and then pass a flag when you need different behavior. You don't want to change the shared procedure so it needs to know what program is calling it.
Move all logic of the procedure to a new one that has an input
parameter.
Call that procedure from the original .p
Call the new procedure from the procedure that needs the extra parameter.
Optional
Gradually replace all runs of original.p to new.p
Remove original.p once you're sure all runs have been changed.
Depending on your OpenEdge version you could move the logic to a class instead of a procedure. In the class you can use overloading