There is a difference between Unique key and unique index. A unique key is a unique index but Unique key can have only one null value and unique index can have multiple null values, try this: Unique key: CREATE TABLE tbl_TestUniquekey (ID INT) GO ALTER TABLE tbl_TestUniquekey ADD CONS...
Can SQL Profiler give you the Missing Index information? Can Symmetric keys be used in a view? Can table-valued parameter be null? Can the "print" command be told not to send a "newline"? Can we alias name for temp table Can we creating index on non unique value columns on temporary...
For example if all legitimate DocID are positive integers you could assign unique negative integers to the ones where this is not applicable (instead of NULL) and then create a unique index on that. Table2 could then reference Table1(DocID) in a foreign key and addit...
The reason is that the query optimizer, knowing that a column cannot have a NULL value, can exclude special tests for such values, like in the NOT IN vs. NOT EXISTS case. You can see for instance this blog, where it is shown that not declaring a field NOT NULL...
Default values for struct DefaultValue Attribute for property of type Color Defining a fixed size array inside a structure Delegate to an instance method cannot have null 'this' Delegates in an Abstract Class? delet the common iteams in list in C# Delete a directory and all its contents Delete...
Does the node having a heading tag(Boolean): We check recursively started from the node and going up its parent whether each node is a Heading Element. We stop when the parent becomes null indicating we have reached the topmost ancestor or when we encounter a heading element. ...
You can have only one primary key. However, you can have as many indexes as you want that have a unique constraint on them. A unique index does pretty much the same thing as a primary key. for example :- CREATE TABLE Persons ( P_Id int NOT NULL, LastName varchar(255) NOT NULL, ...
I have an array a with recurring elements, and a second array, b, containing the sorted, unique values from a (as well as an auxilliary "index array", c):a = np.array(['Bob', 'Anna', 'Bob', 'Charly', 'Bob']) b = sorted(np.unique(a)) c = np.arang...
You may not have thought of it but you can apply these effects to all or some of the words in: Headings Links Lists (Not Tasks) Blockquotes Table cell values HTML entities (except strikethrough) Hidden (Spoiler only) These do not work for the obvious ones (Horizontal Rules, Images, and...
But if you have the values for some_column_id and some_type, the combination of which are known to be unique. And you want to update some_value if exists, or insert if not exists. And you want to do it in just one query (to avoid using a transaction). This might be a solution...