I have two variables, like Stefan and StefanDouble. I have a String variable that contains for "Stefan". How can I get the contents of a variable with the same name and a variable with Double at the end? Is there any reason to do this?
Any time you find yourself storing a variable name in another variable, you should instead store those "variables" inside a table. Real variables are for storing information that's inherent to your algorithm, while tables are for storing unknown amounts of data.
local myVars = {
Stefan = 1,
StefanDouble = 2,
}
local myString = 'Stefan'
print(myVars[myString])
print(myVars[myString .. 'Double'])
Related
I am creating an SSIS package which has an execute SQL task and it passes result set variable to a for each loop container.
My Sql Query is:
Select distinct code from house where active=1 and campus='W'
I want the execute sql task to run this query and assign its results to a variable which is passed to a for each loop container which should loop through all the values in the result set.
But my execute sql task fails with error:
The type of the value (DBNull) being assigned to variable
"User::house" differs from the current variable type (String)
Now i have done my research and i have tried assigning the variable datatype Object but did not work. I tried using cast in my sql query and that also did not work.
Since my query returns multiple rows and one column, i am not sure how i can assign a datatype to the whole query?
Sample:
Code
AR
BN
CN
It sounds like you have a variety of issues in here.
Result Set
The first is in your Execute SQL Task and the need for agreement between the Result Set specification and the data type of the Variable(s) specified in the Result Set tab. If you specify Full Resultset, then the receiving object must be of type System::Object and you will only have 1 result set. The type of Connection Manager (ODBC/OLE/ADO) used will determine how you specify it but it's infinitely searchable on these fine forums.
The other two options are Single Row and XML. In 13 years of working with SSIS, I've never had cause to specify XML. That leaves us with Single Row. For a Single Row Result Set, you need to provide a variable for each column returned and it needs to be correctly typed.
To correct your issue, you need to declare a second variable. I usually call my rsObject (record set object) and then specify the data type as System.Object.
For Each Loop Container
Your For Each Loop Container will then be set with an Enumerator of "Foreach ADO Enumerator" and then the ADO object source variable will become "User::rsObject"
In the Variable Mappings, you'll specify your variable User::house to index 0.
Testing
Given a sample set of source source data, you can verify that you have your Execute SQL Task correctly assigning a result set to our object and the Foreach Loop Container is properly populating our variable.
SELECT DISTINCT
code
FROM
(
VALUES
('ABC', 1, 'w')
, ('BCD', 1, 'w')
, ('CDE', 0, 'w')
, ('DEF', 1, 'w')
, ('EFG', 1, 'x')
) house(code, active, campus)
WHERE
active = 1
AND campus = 'w';
If you change the value of campus from w to something that doesn't exist, like f then things will continue to work.
However, the error you're receiving can only be generated if the code is a NULL
Add one more entry to the VALUES collection like
, (NULL, 1, 'w')
and when the For Each Loop Container hits that value, you will encounter the error you indicate
The type of the value (DBNull) being assigned to variable "User::house" differs from the current variable type (String)
Now what?
SSIS variables cannot change their data type, unless they're of type Object (but that's not the solution here). The "problem" is that you cannot store a NULL value in an SSIS variable (unless it's of type object). Therefore you need to either exclude the rows that return a NULL (AND code IS NOT NULL) or you need to cast the NULL into sentinel/placeholder value as a substitute (SELECT DISTINCT ISNULL(code, '') AS code). If an empty string is a valid value, then you need to find something that isn't - "billinkcisthegreatestever10123432" is unlikely to exist in your set of codes but that might be a bit excessive.
Finally, think about renaming your SSIS variable from house to code. You might be able to keep things straight but some day you'll hand this code over to someone else for maintenance and you don't want to confuse them.
A picturesque answer https://stackoverflow.com/a/13976990/181965
the variable "User::house" is string , so , did you use it in result set?
you need declare son "object" var for result set
result set
then declare a string variable for every single Code from your result
For Each Loop Container
good luck
I've got the following problem:
I do gather that ProductId variable is assigned with the first value and then only that value is used when I refer to ${productId}.
I was trying to apply ${__counter()} to reference name in RegexExtractor,
but then BeanShellAssertion fails to set the property.
How should I properly work this around?
You can use __V() function in order to combine 2 variables.
I.e. if you have 2 variables like:
productId
counter
And would like to evaluate i.e. ${productId_1}, ${productId_2}, etc.
It should be as simple as:
${__V(productId${counter})}
Same approach applies to __counter() function:
${__V(productId_${__counter(,)})}
Demo:
See How to Use JMeter Functions posts series for comprehensive information on above and other functions
ProdGroup
please store the product Id property as prod_id_1, prod_id_2,...prod_id_n or according to you convenience
How to to that ?
in post processor "Parameters" section use ${__counter(FALSE,)} and in the script part try getting that String counter = arg[0] and convert that to integer and store it to a script variable by default arg[0] value is String
int c= arg[0] as Integer //this is groovystyle check in your way to convert as int
now props.put("prod_id_"+c,"extractedfrom_response")
BID:
In you Bid group add a user defined variable section add the variable
"prod_id" and value is empty
Define a counter start with the same counter 1 and give counter reference name [if your counter value in prod group was 0 then here also it must start with zero]
script sampler convert all the props to the variables
Enumeration e = props.propertyNames();
while (e.hasMoreElements()) {
String propertyName = e.nextElement().toString();
if (propertyName.startsWith("prod_id_")) {
vars.put(propertyName, props.getProperty(propertyName));
}
}
With this you have converted properties to variables named prod_id_1 ...to ... prod_id_n
In http sampler user reference as ${__V(prod_id_${counterreference in step 2})} will do your job
For each thread the counter will increment by default
user ${__threadNum} or ${counter reference name} in sampler labels for debugging.
Hope this helps. Please let us know if still problem is there.
I have slices with some variable names
like
strList := ['abcd', 'efgh', 'ijkl']
and I want to make it to variables names(to make some object iterably)
What I curious is that how can I make strings value to variable name. (in code)
like strList[0] seems not allowed....
Thanks for your help!
Since your strings will be read at runtime and your variable names will be checked at compile time, it's probably not possible to actually create a variable with a name based on a string.
However, you can make a map that stores values with string keys. For example, if you wanted to hold integer values inside something you can look up using the values "abcd", "efgh", etc., you would declare:
myMap := map[string]int {
"abcd": 1,
"efgh": 2,
"ijkl": 3,
}
and you could then read those values with e.g. myMap["abcd"] // 1.
I think you want something like http://play.golang.org/p/M_wHwemWL6 ?
Note that the syntax for a slice literal uses {}'s not []'s.
If we compare ABAP field symbols and data references with the pointer in C, we observe :-
In C, say we declare a variable "var" type "integer" with default value "5".
The variable "var" will be stored some where in memory, and say the memory address which holds this variable is "1000".
Now we define a pointer "ptr" and this pointer is assigned to our variable.
So, "ptr" will be "1000" and " *ptr " will be 5.
Lets compare the above situation in ABAP.
Here we declare a Field symbol "FS" and assign that to the variable "var".
Now my question is what "FS" holds ? I have searched this rigorously in the internet but found out many ABAP consultants have the opinion that FS holds the address of the variable i.e. 1000. But that is wrong. While debugging i found out that fs holds only 5. So fs (in ABAP) is equivalent to *ptr (in C). Please correct me if my understanding is wrong.
Now lets declare a data reference "dref" and another filed symbol "fsym" and after creating the data reference we assign the same to field symbol . Now we can do operations on this field symbol. So the difference between data refernec and field symbol is :-
in case of field symbol first we will declare a variable and assign it to a field symbol.
in case of data reference first we craete a data reference and then assign that to field symbol.
Then what is the use of data reference? The same functionality we can achive through field symbol also.
The field-symbol is much like a pointer, but one that you can only access in a dereferenced form. In other words, it will hold, internally, the memory address of the variable that was assigned to it, but it will not allow you to see the memory address, only the data that is stored in the variable that it points to. This can be proved, because if you change the contents of a field-symbol that points to an internal table line, you'll see that the changes will be made directly in the line.
A data reference acts like a simple pointer, except that you can't increment or decrement the memory address like in C (ptr++, ptr-- and such). It differs from a field-symbol because you can compare two data references to check if they point to the exact same spot in the memory. Comparing two field-symbols will be a simple value comparison. Another difference is that you can allocate memory dynamically by creating data references, with the CREATE DATA command. A field-symbol can only be assigned to an already allocated variable.
Although data references and field symbols look very similar and are often used in a similar fashion (see the other answers), they are fundamentally different.
Data references are variables that store a value, just like a string or an integer. They have a fixed size in memory and a content. The only difference is that these references are pointers to other data objects, i. e. the content has a special meaning. They can point nowhere, they can be dereferenced, you can pass them along to other routines, you can manipulate either the pointer (GET REFERENCE) or the value it points to. Nothing special to it, really - just pointers as you know them from your favorite programming language.
Field Symbols are no "real" variables. The documentation states that
They do not physically reserve space for a field
Field Symbols are really only clever manipulations of the local symbol table of the ABAP VM. I'll try to illustrate this - note that this is a heavily simplified model. Let's say you declare three variables:
DATA: my_char TYPE c,
my_int TYPE i,
my_ref TYPE REF TO i.
Then the symbol table will contain - among others - entries that might look like this:
name type size addr
------------------------------
MY_CHAR c 1 0x123456
MY_INT i 4 0x123457
MY_REF r ? 0x123461
(I'm not sure about the actual size of a reference variable.)
These entries only point to an address that contains the values. Depending on the scope of these variables, they might reside in totally different memory areas, but that's not our concern at the moment. The important points are:
Memory has to be reserved for the variables (this is done automatically, even for references).
References work just like all the other variables.
Let's add a field symbol to this:
FIELD-SYMBOLS: <my_fs> TYPE any.
Then the symbol might look like this:
name type size addr target
--------------------------------------
MY_CHAR c 1 0x123456
MY_INT i 4 0x123457
MY_REF r ? 0x123461
<MY_FS> *
The field symbol is created in its initial state (unassigned). It doesn't point anywhere, and using it in this state will result in a short dump. The important point is: It is not backed by "heap" memory like the other variables. Let's
ASSIGN my_char TO <my_fs>.
Again the symbol might look like this:
name type size addr target
--------------------------------------
MY_CHAR c 1 0x123456
MY_INT i 4 0x123457
MY_REF r ? 0x123461
<MY_FS> * MY_CHAR
Now, when accessing <my_fs>, the runtime system will recognize it as a field symbol, lookup the current target in the symbol table and redirect all operations to the actual location of my_char. If, on the other hand, you'd issue the command
GET REFERENCE OF my_int INTO my_ref.
the symbol table would not change, but at the "heap address" 0x123461, you'd find the "address" 0x123457. Just a value assignment like my_char = 'X' or my_int = 42 * 2.
This is, in a very simplified version, the reason why you cannot pass field symbols as changing parameters and allow them to be reassigned inside the subroutine. They do not exist in the same way that other variables do, and they have no meaning outside of the scope of the symbol table they were added to.
A field symbol, which has been around in ABAP much longer, allows you to manipulate and pass values of fields at runtime, without knowing the name of the field beforehand. Consider this use case: You have a structure with 20 fields, you can reference each field by name and assign it to a field symbol, and then change the value of a particular field etc.
A data reference (TYPE REF TO DATA), which is a relatively newer addition to ABAP, allows you to instantiate data at runtime without knowing the type beforehand using the 'CREATE DATA' statement.
For an example of the use of CREATE DATA, see the following SAP Help page. It shows you how you can for example get a reference to a reference object (i.e. ABAP Objects reference) using CREATE DATA, which is something you could not do with a field symbol: http://help.sap.com/abapdocu_70/en/ABAPCREATE_DATA_REFERENCE.htm
Writing a function in Lua, which creates two tables. I want the tables to be assigned to the value name with an x added, and one with a y added. For example if name was line, it would create two tables linex and liney, but I can't figure out how to do it. The following obviously doesn't work (and is just for display purposes) but how would I go about doing this?
function makelinep(x,y,minrand,maxrand,name,length)
name..x = {}
name..y = {}
Later I hope to access "linex" and "liney" after values have been written.
If you want these in the global name space you would use
_G[name..'x']={}
_G[name..'y']={}
For a module you'd use _M in place of _G.