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SQL ON DELETE CASCADE, Which Way Does the Deletion Occur?
...n you try to delete on table BookCourses only the table itself is affected and not on the Courses
follow-up question: why do you have CourseID on table Category?
Maybe you should restructure your schema into this,
CREATE TABLE Categories
(
Code CHAR(4) NOT NULL PRIMARY KEY,
CategoryName VARC...
Inline functions in C#?
How do you do "inline functions" in C#? I don't think I understand the concept. Are they like anonymous methods? Like lambda functions?
...
Hashing a dictionary?
...thon 3.3 returns different results between sessions). make_hashable() will convert the object into nested tuples and make_hash_sha256() will also convert the repr() to a base64 encoded SHA256 hash.
import hashlib
import base64
def make_hash_sha256(o):
hasher = hashlib.sha256()
hasher.updat...
libcurl的使用总结 - C/C++ - 清泛网 - 专注C/C++及内核技术
..._init()初始化libcurl
2. 调用 curl_easy_init()函数得到 easy interface型指针
3. 调用curl_easy_setopt设置传输选项
4. 根据curl_easy_setopt设置的传输选项，实现回调函数以完成用户特定任务
5. 调用curl_easy_perform（）函数完成...
Nullable type issue with ?: Conditional Operator
...nch of times already. The compiler is telling you that it doesn't know how convert null into a DateTime.
The solution is simple:
DateTime? foo;
foo = true ? (DateTime?)null : new DateTime(0);
Note that Nullable<DateTime> can be written DateTime? which will save you a bunch of typing.
...
When to use LinkedList over ArrayList in Java?
...nkedList. If you're not sure — just start with ArrayList.
LinkedList and ArrayList are two different implementations of the List interface. LinkedList implements it with a doubly-linked list. ArrayList implements it with a dynamically re-sizing array.
As with standard linked list and array op...
What is the point of noreturn?
...n your example).
This can be used by compilers to make some optimizations and generate better warnings. For example if f has the noreturn attribute, the compiler could warn you about g() being dead code when you write f(); g();. Similarly the compiler will know not to warn you about missing return ...
Get boolean from database using Android and SQLite
How can I obtain the value of a boolean field in an SQLite database on Android?
10 Answers
...
Swapping column values in MySQL
I have a MySQL table with coordinates, the column names are X and Y. Now I want to swap the column values in this table, so that X becomes Y and Y becomes X. The most apparent solution would be renaming the columns, but I don't want to make structure changes since I don't necessarily have permission...
What is the combinatory logic equivalent of intuitionistic type theory?
...tution), it'll be handy to represent intermediate stages in the process of converting terms with binding to their combinatory form.
Here's normalization:
norm :: Unty a -> Unty a
norm (f :. a) = norm f $. a
norm c = c
($.) :: Unty a -> Unty a -> Unty a -- requires first a...