DBMS Question
What is Bookmarking, Row id and covering index in SQL server?

Question

DBMS Question

What is Bookmarking, Row id and covering index in SQL server?

Accepted Answer

Bookmarks : Bookmarks let consumers quickly return to a row. With bookmarks, consumers can access rows randomly based on the bookmark value. The bookmark column is column 0 in the rowset. The consumer sets the dwFlag field value of the binding structure to DBCOLUMNSINFO_ISBOOKMARK to indicate that the column is used as a bookmark.

ROWID : ROWID is nothing but the physical memory location on which that data/row is stored.ROWID basically returns address of row. It uniquely identifies row in database. ROWID is combination of data object number, data block in datafile, position of row and datafile in which row resides. ROWID is 16 digit hexadecimal number whose datatype is also ROWID Or UROWID

Covering index : A covering index is one which can satisfy all requested columns in a query without performing a further lookup into the clustered index.

Accepted Answer

data required for a query without having to access the actual table.

Accepted Answer

A regular index that provides all the data required for a query without having to access the actual table..

Top PolicyBazaar Senior Database Developer interview questions & answers

Popular interview questions of Senior Database Developer