Karteikarten
Database Final
Karten in diesem Stapel (27)
- 1DBMS File Structures-File records are mapped onto a disk is formatted into several blocks
- A file is a sequence of records stored in binary format
- Relative data and information is stored collectively in file formats - 2Heap file organizationHeap file does not support any ordering, sequencing, or indexing on its own
- 3Sequential file organizationRecords are placed in the file in some sequential order based on the unique key field or search key
- 4Hash file organizationThe hash function determines the location of disk block where the records are to be placed
- 5Clustered file organizationNot good for large databases. Related records from one or more relations are kept in the same disk block
- 6Match the file operation to its behavior OpenA file can be opened in one or two modes: read mode write mode
- 7Match the file operation to its behavior LocateEvery file has a file pointer, which tells the current position where the data is to be read or written
- 8Match the file operation to its behavior ReadThe very next data to the file pointer is read
- 9Match the file operation to its behavior Writeenables data to be edited: deletion, insertion or modification
- 10Match the file operation to its behavior Closeremoves all the locks; saves the data; releases all the buffers and file handlers
- 11Primary indexThe data file is ordered on a key field
- 12Secondary indexmay be generated from a field which is a candidate key
- 13Clustering indexis defined on an ordered data file
- 14Which of the following are types of ordered indexing?Dense index, Sparse index
- 15Which of the following best describes dense indexthere is an index record for every search key value in the database
- 16Which of the following best describes sparse index?To search a record, we first proceed by index record and reach at the actual location of the data
- 17Which of the following best describes multilevel index?There is an immense need to keep the index records in the main memory so as to speed up the search operations
- 18Regarding B+ Tree indexing, match the term to its destination or the action to its behavior. B+ Tree insertionare filled from bottom and each entry is done at the leaf node
- 19B+ Tree Deletionunderflow is tested, if underflow occurs, distribute the entries from the nodes left to it
- 20Internal nodescontain at least [n/2] pointer, except the root node
- 21Leaf nodescontain at least [n/2] record pointers and [n/2] key values
- 22Hashing: BucketA unit of storage
- 23Hash functionA mapping function that maps all the set of search-keys to the address where actual records are placed
- 24Static hashingWhen a search-key value is provided, the hash function always computes the same address
- 25collisionThe condition of bucket-overflow
- 26Overflow chainingA new bucket is allocated for the same hash result and is linked after the previous one
- 27Linear probingWhen a hash function generates an address at which data is already stored, the next free bucket is allocated to it