#Caché

In this article I would like to tell you about macros in InterSystems Caché. A macro is a symbolic name that is replaced with a set of instructions during compilation. A macro can “unfold” in various instruction sets each time it is called, depending on the parameters passed to it and activated scenarios. This can be both static code and the result of ObjectScript execution. Let's take a look at how you can use them in your application.

By now it's a commonplace how to implement a basic REST API in Caché and there is good documentation about it here: REST in Caché

A question that comes up from time to time is:

How can I make a parameter in my REST url optional?

Simply put, is it possible to create a URL map in Caché that maps a URL like this:

http://server/API/object///old

While this might look odd, this is actually a valid URL. You can read the details in RFC3986 section 3.3.

What is a major difference between $case and $select?

hi

  I query large mount of rows from one table with JDBC, and will prompt <store> error.  I found that it was out of process memory (default 16M, max 49M in version 2010.2) .

  so my question is : how to release memory for large  mount of rows  query? or how to resolve this error?

I get a third party routine which outputs some messages to standard output during execution.

Is it possible that I could direct the messages to other device so my terminal would never see this messages?

Thanks.

Greetings,  

What methods are available to position a cursor on a screen to begin writing as not to disrupt other areas of the screen?  I have used ?# , ie: ?5 but this is destructive from the let to character 5.  I would like to enter a command that will position at row,col and then start writing?  Can I create a window in a window type display to write text and then when done viewing, remove it?

Please advise,

Thanks in advance for everyone's time.

I have a query string that I am creating programmatically, based on some user inputs.  The user might search on 5 fields, or 8 fields, or no fields.

In my sql statment, some of these fields require parameters in the %Execute statement.

For example:

if user picks lastname, sql = "select * from person where lastname = ?"

if user also picks age, sql = "select * from person where lastname=? and age > ?"

I then have these lines of code to create my result set:

set statement = %SQL.Statement

statement.%Prepare

resultset = statement.%Execute(param1, param2)

-- but it might be 

Type 1:

^global(key1,key2,key3,val1) = ""
^global(key1,key2,key3,val2) = ""
^global(key1,key2,key3,valn) = ""

Type 2:

^global(key1,key2,key3) = $lb(val1,val2,.....valn)

the number of val may be just dozens, but also possible to 10K

Thanks.

Hi Community!

Please find the Developer Community video of the week on the InterSystems Developers YouTube Channel: 

Upgrades - Minimizing Business Disruption

More calls in parallel to a single .Net Gateway can yield better performance, but too many could cause problems. What is the "Right" number? What do you do/recommend?

Hi,

Is it possible to use the value of a column that is populated by its own subquery,  in the WHERE clause of the outer-query ?

The following fails (it does not parse syntactically):

SELECT A, B, (SELECT S1 FROM Table2) "C" FROM Table1 WHERE C>10

I guess I could wrap it up as in inner query of it's own - this way (which works) :

Select * from 
(SELECT A, B, (SELECT S1 FROM Table2) "C" FROM Table1)
where C>10

but I was wondering if there was some syntax in the original snippet that I could do instead.

Thanks - Steve

Hello! So, my knowledge on the Cache database is extremely limited, and I was hoping I could find some assistance here. I'm connecting to the DB via ODBC. The table(s) I'm interested in are named as such nameYYYYMMDD. So each day, a new table is created with logs. We'd like to grab these records each day, for the previous day's logs. 

Hi all,

I was wondering if there is any way to trigger the compilation of a class based on the compilation of another (unrelated) class. For example:

Class 1 = test.class

Class 2 = test.class.type.one

Class 3 = test.class.type.two

Every time class 2 or class 3 is compiled in Studio I would like to have class 1 automatically compiled as well.

The reason I need this is because class 1 has a method with CodeMode set to objectgenerator which generates some code based on what is found in classes 2 and 3.

Below are the output messages when Cache start.

Allocated 178MB shared memory: 1MB global buffers, 26MB routine buffers

I try to configure the global buffer size by [System] -> [Configuration] -> [Memory and Startup] from SMP,

but it seems like the changes does not apply to the global buffer.

Thanks for your help.

I have a class and I would like to dynamically change its selectivity attribute in run-time and then call $system.OBJ.Compile to

recompile the class. I have changed the selectivity to a global, but it seems like it does not work. Any suggestions? Thanks.

<Property name="field1">
<AverageFieldSize>8.91</AverageFieldSize>
<Selectivity>^selectivity</Selectivity>
</Property>
 

hi

   I want to update  some columns in one table like this:

    update table1 set col1=%SYSTEM.Encryption_AESCBCEncrypt(col1, 'key')

but the error is 

ERROR #5540: SQLCODE: -359 Message: User defined SQL Function '%SYSTEM.ENCRYPTION_AESCBCENCRYPT' does not exist

what's the corect syntax?  Thanks!

Hi,

I have a situation where I write a character stream to a file. The file content gets signed and the signature is sent to a service provider together with the file content.

The signing is done using openssl.

This works perfectly on a dev PC, which is runnning Windows and has a little-endian architecture.

The problem is as soon as I do this on the server, which has a big-endian architecture, the signed value is incorrect according to the service provider.

The content is signed using RSA SHA256 with PSS padding.

I've had a look at $nconvert, $sconvert, etc., but can't get to a solution.

hi

  is there a built in function for convert string to hex.  for example

"abc"   convert to "616263"

thanks

Greetings, 

How can I store a global name in a variable, ie: x="^G" and then use x like this, as if it were the global:  y=$o(x)  ?

Please advise,

Thanks... 

Greetings,

If given a global, how can I discover information on that global?  More specifically,  how can I discover how many indices it contains?  ie:  ^G(1,2,3,4,5)   How can I discover that there are 5 subscripts within the Global ^G if I did not already know.

Please advise, and thanks in advance for everyone's time.

It is my understanding that when a routine accesses a global it is temporarily stored in global memory. While the global is within global memory, any other routine would be able to readily access the global from memory and not from disk so long as the same node is being utilized.

For example, RoutineB() would be able to access ^Global(1) and ^Global(1,2) since RoutineA() utilized them, but RoutineB() would have to read ^Global(1,7) from disk as it was not utilized by RoutineA().

Hi everyone

Is there any way to change a class definition (especifically a query definition during the compilation time)?
The idea is: 
    I have an abstract class with a parameter where I will define the ROWSPEC of a query and some methods to populate e temporary table
The implementation class will override the parameter, specifying the ROWSPEC of this implementation, and the methods will populate the rows in the same format as the ROWSPEC.

Hi 

I have two persistent classes defined. Lets call it Parent and Child.

Child class is one of the property of Parent Class.

I would like to define a index on Child class.

So what is the default behaviour I defined a index on a non simple data type member?

Any possibility that I could customized the behaviour ? For example. Child class has three properties.

Could I configure the index to index any combinations of these three properties?

Thanks for your help.

I'm trying to recreate a smaller copy of our DEV machine on a sandbox instance.  I installed a new instance, and thought it would be a good idea to copy over a few cache.dat files from the critical namespaces (but not all of them), and start from there.

However, I can't compile any UI files in my new instance because I'm getting a <PROTECT> error on the %qCacheMsg global -- for any element that displays text (i.e. the first <label> that's encountered) the generated code is trying to get text from the global  ^%qCacheMsg("%Utility","en",node) = text -- from a node that doesn't exist.

Hi,

I have a UrlMap like the one below.

<Route Url="/Results/:queryID" Method="POST" Call="QueryResults"/>

What if I have to pass two parameters to QueryResults, how to do configure Url?

Something like Url="/Results/:queryID/:parameter2"   ?

Thanks.

I have a query text that I need to execute and return results as xml.

It may be an SQL query or an MDX query. Is there some easy way to determine which one is it?

Any ideas?

Hi all,

We faced a problem where we would like to map a $lb object to its corresponding data model structure in order to later on export it as JSON.

So imagin that we have something like this that actually maps to a persistent table with its structure. 

$lb("",,,,,"",,,"BOOLEAN","0",2,2,"1",,"bla",$lb(,,"bla","20050502123400"),"",1,"bla",,0)

Is there a way to transform this $lb (without the need of openig the object itself) to a JSON object with the proper table fields as properties?

Many thanks

Hy.

I set up cache in container, which is working fine. But when accessing managment portal the default user was alway Unknown user and no username or password were required. So i disabled the Unknow user in the Security section, but now i keep getting an error access denid. 

Hi!

I have a global-mapped class that I want to add a transient property through (or at least, not stored on the database). This property is the sum total of various charge classes that are linked to the class via child relationships.

I want this new transient property to be visible at least via SQL.

Greetings,

How do I organize a wildcard search with respect to a database search?

Example of what I am trying to do:  s x=$o(^G("ABC","A*",x))

Trying to navigate through the ^G global for all occurrences of "ABC", and "A*" ("A"+wildcard) but I am new to M and don't know positively how to do this.  Perhaps I don't use an "*" at all, rather; another convention altogether.

Please advise.

Thanks in advance for everyone's assistance.