parameters

问题 I need to know what are the valid characters to use in a SQL parameter name. Given something simple like SELECT * FROM tblTest WHERE testid = @[X] , if X contains a hyphen, for instance, the statement will fail. What are the valid characters for parameter names? 回答1: Search for "Identifiers" in your SQL Books online, and you should find: Rules for Regular Identifiers The rules for the format of regular identifiers depend on the database compatibility level. This level can be set by using sp

问题 Is it possible to define a function that takes in a parameter that must implement two interfaces? (The two interfaces are ones I just remembered off the top of my head; not the ones I want to use) private void DoSomthing(IComparable, ICollection input) { } 回答1: You can: 1) Define an interface that inherits both required interfaces: public interface ICombinedInterface : IComparable, ICollection {... } private void DoSomething(ICombinedInterface input) {... } 2) Use generics: private void

问题 I am developing a Windows Application and use a Crystal Report in it. I am able to pass value to one parameter of Crystal Report. Now, I have added one more parameter to Crystal Report, but confused about what modification I have to make in below code. Below code is written to pass value to one parameter of CR. Private Sub btnLoadBatch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLoadBatch.Click Try Dim cr As New crMonthwiseBatch Dim oBatches As New Batches Dim

问题 Let's say a have a stored procedure SetCustomerName which has an input parameter Name, and I have a table customers with column Name. So inside my stored procedure I want to set customer's name. If I write UPDATE customers SET Name = Name; this is incorrect and I see 2 other ways: UPDATE customers SET Name = `Name`; UPDATE customers SET customers.Name = Name; First one works, but I didn't find in documentation that I can wrap parameters inside ` characters. Or did I miss it in the

问题 Hi I'm trying to create a function that dynamically creates a delegate with the same return value and the same parameters as a MethodInfo it receives as parameter and also and this is very important the same parameter names! What I did so far is create a function that returns a lambda that receives the same parameter types and has the same return value as the MethodInfo but it doesn't have the parameter names: static void Example() { Person adam = new Person(); MethodInfo method = typeof

问题 Hi I'm trying to create a function that dynamically creates a delegate with the same return value and the same parameters as a MethodInfo it receives as parameter and also and this is very important the same parameter names! What I did so far is create a function that returns a lambda that receives the same parameter types and has the same return value as the MethodInfo but it doesn't have the parameter names: static void Example() { Person adam = new Person(); MethodInfo method = typeof

问题 I was wondering if it's possible to write a function that accepts multiple generic types as follows: public int void myfunction(Set<T> a, Set<T> b) { return 5; } Set<Integer> setA = new HashSet<Integer>(); Set<String> setB = new HashSet<String>(); int result = myfunction(setA, setB); Will that work? Does the generic in each parameter mean that each parameter must have the same type T that's generic? 回答1: Yes - it's possible (though not with your method signature) and yes, with your signature

问题 Is it possible to specify a method block parameter in Objective-C without using a typedef? It must be, like function pointers, but I can't hit on the winning syntax without using an intermediate typedef: typedef BOOL (^PredicateBlock_t)(int); - (void) myMethodTakingPredicate:(PredicateBlock_t)predicate only the above compiles, all these fail: - (void) myMethodTakingPredicate:( BOOL(^block)(int) ) predicate - (void) myMethodTakingPredicate:BOOL (^predicate)(int) and I can't remember what other

问题 How solve a system of ordinary differential equation ..an initial value problem ....with parameters dependent on time or independent variable? say the equation I have Dy(1)/dt=a(t)*y(1)+b(t)*y(2); Dy(2)/dt=-a(t)*y(3)+b(t)*y(1); Dy(3)/dt=a(t)*y(2); where a(t) is a vector and b(t) =c*a(t); where the value of a and b are changing with time not in monotone way and each time step. I tried to solve this using this post....but when I applied the same principle ...I got the error message "Error using

问题 I am a little bit confused about pass an array in C/C++. I saw some cases in which the signature is like this void f(int arr[]) some is like this void f(int arr[], int size) Could anybody elaborate what's the difference and when and how to use it? 回答1: First, an array passed to a function actually passes a pointer to the first element of the array, e.g., if you have int a[] = { 1, 2, 3 }; f(a); Then, f() gets &a[0] passed to it. So, when writing your function prototypes, the following are