Software Applications Programming Errors and solutions.

A covering index is a non-clustered index which includes all columns referenced in the query and therefore, the optimizer does not have to perform an additional look-up to the table in order to retrieve the data requested. As the data requested is all indexed by the covering index, it is a faster operation. covering index is a non-clustered index which stores additional columns at leaf level to avoid bookmark lookup to heap/clustered index.this is typically created using INCLUDE clause. Let say we have a table tab1 and we have columns starts from column 1 to 10. and we have clustered index on column1 and non clustered index on column 2 . for example you written a query select * from tab1 where column 2=200. this query first will go and look for the matching data in non clustered index and because of our query want to retrieve all the columns it will perform key look up , not helathy. this time i had one more non clustered index on column3 and column4 ,composite.in this case our query

Clustered index which reordered the table and saved separately as index table(data pages stored as B-tree) there can be one clustered index per db & Non clustered index is typically a index(data pages stored as heap) A table can have only one clustered index with many non clustered indexes. The leaf nodes of the cluster index stores data pages and non clustered index stores key values(where as table includes clustered index) or rid's(table contains non cluster index only).

The distinction between stack and heap relates to programming. When you look at your computer memory, it is organized into three segments: •text (code) segment •stack segment •heap segment text (code) segment The text segment (often called code segment) is where the compiled code of the program itself resides. When you open some EXE file in Notepad, you can see that it includes a lot of "Gibberish" language, something that is not readable to human. It is the machine code, the computer representation of the program instructions -The two sections other from the code segment in the memory are used for data. stack segment The stack is the section of memory that is allocated for automatic variables within functions. Data is stored in stack using the Last In First Out (LIFO) method. This means that storage in the memory is allocated and deallocated at only one end of the memory called the top of the stack. Stack is a section of memory and its associated registers that