data structures using thereforethe inverted file system consists of an index file in addition to document file (also known as text fileit is this index file that contains all the keywords which may be used as search terms for each keywordan address or reference to each location in the document where that word occurs is stored there is no restriction on the number of pointers associated with each word for efficiently retrieving word from the index filethe keywords are sorted in specific order (usually alphabeticallyhoweverthe main drawback of this structure is that when new words are added to the documents or text filesthe whole file must be reorganized thereforea better alternative is to use -trees -tree indices database is defined as collection of data organized in fashion that facilitates updatingretrievingand managing the data (that may include any itemsuch as namesaddressespicturesand numbersmost organizations maintain databases for their business operations for examplean airline reservation system maintains database of flightscustomersand tickets issued university maintains database of all its students these real-world databases may contain millions of records that may occupy gigabytes of storage space for database to be usefulit must support fast retrieval and storage of data since it is impractical to maintain the entire database in the memoryb-trees are used to index the data in order to provide fast access for examplesearching value in an un-indexed and unsorted database containing key values may take running time of (nin the worst casebut if the same database is indexed with -treethe search operation will run in (log ntime majority of the database management systems use the -tree index technique as the default indexing method this technique supersedes other techniques of creating indicesmainly due to its data retrieval speedease of maintenanceand simplicity figure shows -tree index - - - - - - - - - - - - amar david ben emily gauri henry charan fred inder dorsy-address emily-address fred-address figure -tree index james mercy parul simi kim lorleen naresh quinn rusty ted umesh omar pointers to records vimi yasin wills zubir