29 Questions
What is the characteristic of a dense index?
Index records appear for every search-key value in the file.
What is the advantage of sparse index files?
They use less space and have less maintenance overhead for insertions and deletions.
What is the disadvantage of indexed-sequential files?
Their performance degrades as the file grows.
What is a characteristic of B+-tree indices?
They are an alternative to indexed-sequential files.
What is the procedure to locate a record with search-key value K in a sparse index?
Find the index record with the largest search-key value < K and search file sequentially.
What is the advantage of a sparse index on top of a dense index (multilevel index)?
It is a good tradeoff for unclustered index.
What is the assumption made in the simplest file organization approach?
Each record size is fixed
What is a consequence of not moving records on deletion?
Free space is wasted
What is the purpose of a free list?
To store record pointers
What is a characteristic of variable-length records?
Records are of different types
What is an alternative to moving records on deletion?
Linking free records on a free list
What is a consequence of allowing records to cross block boundaries?
Modification is more complex
What type of record type allows variable lengths for one or more fields?
Varchar record
How are null values represented in a record?
Using a null-value bitmap
What is the method of storing records in a file based on the value of the search key of each record?
Sequential
What is the organization of records method that uses a hash function to determine the block of the file where the record should be placed?
Hashing
How can records of each relation be stored in a file?
In a separate file for each relation
What is the main purpose of a multitable clustering file organization?
To store related records on the same block to minimize I/O
What is the primary concern in a sequential file organization when inserting a new record?
Maintaining the sequential order of the file
What is the function of a hash index?
To distribute search keys uniformly across buckets
What is the primary advantage of indexing mechanisms?
Speeding up access to desired data
What is the purpose of an index file?
To facilitate fast access to desired data
What is an example of an access type supported efficiently by indexing mechanisms?
Records with a specified value in the attribute
What is the primary purpose of ordered indices?
To make searching faster
What is a characteristic of a clustered index?
It is used to group records with similar characteristics
What happens when searching for a record in a database with no index?
The DBMS reads the record after reading the specified number of bytes
What is the benefit of using a clustered index in a department-based employee database?
It groups employees by department for faster lookup
What is the purpose of grouping records in a clustered index?
To identify the record faster
What happens to the records which have similar characteristics in a clustered index?
They are grouped together and indexed
This quiz covers secondary indexing, dense and sparse indexing, and their applications in database management. It includes examples and explanations of indexing techniques.
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