Some is not a keyword. There is an option type however, which is a discriminated union containing two things: Some which holds a value of some type. None which represents lack of value. It’s defined as: type ‘a option = | None | Some of ‘a It acts kind of like a nullable type, where … Read more
From the first ISO C++ standard C++98, this is described in 2.5/ Alternative tokens [lex.digraph]: Alternative token representations are provided for some operators and punctuators. In all respects of the language, each alternative token behaves the same, respectively, as its primary token, except for its spelling. The set of alternative tokens is defined in Table … Read more
From Static Classes and Static Class Members (C# Programming Guide) A call to a static method generates a call instruction in Microsoft intermediate language (MSIL), whereas a call to an instance method generates a callvirt instruction, which also checks for a null object references. However, most of the time the performance difference between the two … Read more
In Cassandra if you define UDT or Collection as frozen, you can’t update UDT’s or collection’s individual item, you have to reinsert with full value. A frozen value serializes multiple components into a single value. Non-frozen types allow updates to individual fields. Cassandra treats the value of a frozen type as a blob. The entire … Read more
sum.up is not a valid keyword argument name. Keyword arguments must be valid identifiers. You should look in the documentation of the library you are using how this argument really is called – maybe sum_up?
The MySql EXPLAIN statement can be used either as a synonym for DESCRIBE or as a way to obtain information about how MySQL executes a SELECT statement. The closest equivalent statement for SQL Server is: SET SHOWPLAN_ALL (Transact-SQL) or SET SHOWPLAN_XML (Transact-SQL) From a SQL Server Management Studio query window, you could run SET SHOWPLAN_ALL … Read more
You should be using DATEADD is Sql server so if try this simple select you will see the affect Select DATEADD(Month, -1, getdate()) Result 2013-04-20 14:08:07.177 in your case try this query SELECT name FROM ( SELECT name FROM Hist_answer WHERE id_city=’34324′ AND datetime >= DATEADD(month,-1,GETDATE()) UNION ALL SELECT name FROM Hist_internet WHERE id_city=’34324′ AND … Read more
You ask: Is there a command that can change this maximum length? Is this length the same for other names (columns, tables etc)? The manual answers here: The system uses no more than NAMEDATALEN-1 bytes of an identifier; longer names can be written in commands, but they will be truncated. By default, NAMEDATALEN is 64 … Read more
Can it have characters like “https://stackoverflow.com/”? All examples are from SQlite 3.5.9 running on Linux. If you surround the column name in double quotes, you can: > CREATE TABLE test_forward ( /test_column INTEGER ); SQL error: near “https://stackoverflow.com/”: syntax error > CREATE TABLE test_forward (“/test_column” INTEGER ); > INSERT INTO test_forward(“/test_column”) VALUES (1); > SELECT … Read more
object is a (global) variable. By default it is bound to a built-in class which is the root of the type hierarchy. (This leads to the interesting property that you can take any built-in type, and use the __bases__ property to reach the type called object). Everything built-in that isn’t a keyword or operator is … Read more