I have an EntityA which has an optional attribute int32 result. When I create EntityA I do not set the result attribute. Then later on when I fetch it I expect it to have nil value but for some reason it's set to 3 even though I have not set this attribute.
What's going on here?
1st possible issue:
You have set a default value in the model editor. Select the attribute and check the inspector.
2nd possible issue:
You are retrieving or showing the wrong value. Show the code you are using to find out that result is '3'.
3rd possible issue:
You are setting the value later inadvertently, perhaps in a loop or something similar. Do a text search for the attribute to find a possible occurrence in your code.
Your int32 will be stored wrapped into a NSNumber object. If you don't provide a value, no NSNumber object will be created - sql will treat it as NULL.
The iOS Core Data Programming Guide says:
You can specify that an attribute is optional—that is, it is not
required to have a value. In general, however, you are discouraged
from doing so—especially for numeric values (typically you can get
better results using a mandatory attribute with a default value—in the
model—of 0). The reason for this is that SQL has special comparison
behavior for NULL that is unlike Objective-C's nil. NULL in a database
is not the same as 0, and searches for 0 will not match columns with
NULL.
So, it may be better to either make the attribute mandatory and set it to a distinct value, or to pass in NSNumber from the start.
Related
I am trying to assign the value of this stucture path to a fieldsymbol, but this path does not work because it has a table in it's path.
But with in the debugger this value of this path is shown correctly.
Is there a way to dynamically assign a component of a table line to a fieldsymbol, by passing one path?
If not then I will just read the table line and then use the path to get the wanted value.
ls_struct (Struct)
- SUPPLYCHAINTRADETRANSACTION (Struct)
- INCL_SUPP_CHAIN_ITEM (Table)
- ASSOCIATEDDOCUMENTLINEDOCUMENT (Element)
i_component_path = |IG_DDIC-SUPPLYCHAINTRADETRANSACTION-INCL_SUPP_CHAIN_ITEM[1]-ASSOCIATEDDOCUMENTLINEDOCUMENT|.
ASSIGN (i_component_path) TO FIELD-SYMBOL(<lg_value>).
IF <lg_value> IS NOT ASSIGNED.
return.
ENDIF.
<lg_value> won't be assigned
Solution by Sandra Rossi
The debugger has its own syntax and own logic, it doesn't apply the ASSIGN algorithm at all. With ABAP source code, you have to use ASSIGN twice, the first one to reach the internal table, then you select the first line, and the second one to reach the component of the line.
The debugger works completely differently, the debugger code works only in debug mode, you can't call the code from the debugger (i.e. if you call it, the kernel code used by the debugger will fail). No, there's no "abappath". There are the XSL transformation objects (xpath), but it's slow for what you ask.
Thank you very much
This seems to be a rather unexpected limitation of the ASSIGN statement. Probably worth a ticket to SAP's ABAP language group to clarify whether it's even a bug.
While this works:
ASSIGN data-some_table[ 1 ]-some_field TO FIELD-SYMBOL(<lv_source>).
the same expressed as a string doesn't:
ASSIGN (`data-some_table[ 1 ]-some_field`) TO FIELD-SYMBOL(<lv_source>).
Alternative 1 for (name) of the ABAP keyword documentation for the ASSIGN statement says that "[t]he name in name is structured in the same way as if specified directly".
However, this declaration is immediately followed by "the content of name must be the name of a data object which may contain offsets and lengths, structure component selectors, and component selectors for assigning structured data objects and attributes in classes or objects", a list that does not include the table expressions we would need here.
I'm using Entity Framework to send a query to the database using ExecuteStoreQuery
If (DBEntity.ExecuteStoreQuery(Of Integer)("SELECT COUNT(ReceiptUID) FROM qryRptSrc_Cust_GoodsReceipt_Issues WHERE ReceiptUID = #Recpt", ReceiptUID)(0) > 0) Then ....
Which gives me the error message that my scalar variable #Recpt hasn't been declared. I know what that error message means, but I'm wondering why it's being thrown in this case. ReceiptUID is a Guid with the correct value. The parameters that are passed don't have to be DbParameter objects, they can just be values and it should work fine. I've done it that was in the past before without issue, and even MSDN states
The parameters value can be an array of DbParameter objects or an array of parameter values. If only values are supplied, an array of DbParameter objects are created based on the order of the values in the array.
I could create a DbParameter object instead, but I'd like to know why this case isn't working.
Token answer:
Try #p0 instead of #Recpt
For instance, when to use
GetterUtil.getBoolean()
and when
ParamUtil.getBoolean()?
Are both same, or is it expected to be used differently according to a parameter, a variable, etc? Can you give some examples for both?
Both are util methods to avoid Null-Pointer Exceptions.
GetterUtil internally returns the default type and does the casting too. So in case where someone has passed a null value, it will return default value of the type.
Example:
Assume you have a String value "true", and you are expecting it will always be of type boolean. So you use GetterUtil.getBoolean("true") which will internally do the casting to boolen and return the value as boolean-true. Incase someone passes rubbish characters like "tr", it will be converted to boolean-false.
As mentioned ParamUtil does the same treatment with request parameters. ParamUtil internally uses the GetterUtil to have the above behaviour. It first retrieves the parameter (which always would be a string) and then passes it to GetterUtil.getType() method and in turn returns the proper type.
GetterUtil and ParmUtil both are different classes.
GetterUtil is to get the default values for basic Java data types.
ParamUtil is to retrive the values(of primitive data types) from the HttpReqeust.
Check the source code here for these two classes here
For GetterUtil
http://docs.liferay.com/portal/6.0/javadocs/src-html/com/liferay/portal/kernel/util/GetterUtil.html
For ParamUtil
http://docs.liferay.com/portal/5.1/javadocs/portal-kernel/com/liferay/portal/kernel/util/ParamUtil.java.html
What is the operator or function to test whether two variables of the same custom object type refer to the same object? I've tried
If myObject = yourObject Then
But get a runtime error 438 object doesn't support this property or method. I'm guessing that's telling me to override the '=' operator to test if all the fields of the two objects have the same value. But what I want is to test whether they are the same object.
I'm guessing that's telling me to override the '=' operator to test if all the fields of the two objects have the same value.
No, it tells you the objects don't have a default property which would have been called otherwise, and the returned results compared.
You test reference equality with Is
If myObject Is yourObject Then
You need to serialize the objects somehow and then compare attribute by attribute values. The "is" operator is as dumb as it gets, it only matches if another object is the same instance assigned to the compared variable.
I suggest using a jsonStringify library. I adapted one for my DexTools.xlam open source project https://github.com/dexterial/Dextools/tree/master/Main starting from the Parsing JSON in Excel VBA post. It has much more added features since I added quite a few other excel objects serialization/hashing options and it is made using the vba test driven development that DexTools incorporates. It is still work in progress so dont expect miracles
I have a GUI app written in C++/CLI which has a load of configurable options. I have some overloaded functions which grab values from my data source and I'd like to connect my options to those values.
So here's a couple of data retrievers:
bool GetConfigSingle(long paramToGet, String^% str, char* debug, long debugLength);
bool GetConfigSingle(long paramToGet, bool^% v_value, char* debug, long debugLength);
I was hoping to pass in the checkbox's Checked getter/setter as follows:
result = m_dataSource->GetConfigSingle(CONFIG_OPTION1, this->myOption->Checked, debug, debugLen);
...but for some reason I get an odd compiler error which suggests the Checked value isn't being passed as I'd expect:
1>.\DataInterface.cpp(825) : error C2664: 'bool DataInterface::GetConfigSingle(long,System::String ^%, char*, long)' : cannot convert parameter 2 from 'bool' to 'System::String ^%'
Previously this code passed the checkbox in and modified the values itself, but I'm keen to break the dependency our data collection currently has on windows forms.
So what am I missing here?
[Edit] I've filled out the function definitions as they originally were to avoid confusion - my attempt to reduce the irrelevent information failed.
I'm fairly certain that the CheckBox getter / setter returns a bool.
Figured I'd clarify my comments from above and make it a "real" answer...
When you call Checked, what you're getting back as a return value is a bool that represents the current state of the CheckBox. It is not, however, a reference to the actual data member that holds the CheckBox's state. In fact, a properly encapsulated class shouldn't give access to it. Furthermore, since Checked returns a bool by value, that bool is a temporary object that doesn't necessarily exist by the time GetCongigSingle is called.
This leaves you with several options. Either pass the bools by value, and later set the CheckBox's state, or pass the CheckBox itself by reference and "check" it wherever you want.
The two overload of the method GetConfigSingleFile that you have mentioned both take two arguments whereas you are passing 4 arguments to the method. Are there any default arguments? If yes, can you please reproduce the original method declarations?
Most probably, the 4 argument overload of this method is expecting a String^% as the 2nd argument. This is what the compiler is suggesting anyway. But if we can have a look at the method declarations that could help diagnosing the problem.
This isn't an answer to my question, but worth being aware of - apparently there's a quirk in passing properties by reference.