Tài liệu Database Systems: The Complete Book- P1 doc
Tài liệu Database Systems: The Complete Book- P6 docx
... the block move under the disk head as the entire disk assembly rotates. The time taken between the moment at which the command to read a block is issued and the time that the contents of the ... latency: the time for the disk to rotate so the first of the sectors containing the block reaches the head. X typical disk rotates completely about once every 10 mi...
Ngày tải lên: 21/01/2014, 18:20
Tài liệu Database Systems: The Complete Book- P7 doc
... room for the inserted record in the block at hand, then we simply slide the records within the block and adjust the pointers in the offset table. The new record is inserted into the block, ... having to retrieve the block containing the record. The fact that K exists in the dense index is enough to guarantee the existence of the record with key I(. On th...
Ngày tải lên: 21/01/2014, 18:20
Tài liệu Database Systems: The Complete Book- P9 doc
... shows the complete translation to relational algebra. .&bola the y, the StarsIn from the outer query is joined n-ith the result of the subquery. The selection from the subquery is then ... 16.4.4) to the twvo relations that are the join of the R's and the join of the S's, the estimate will be the product of the two estimates, divided by...
Ngày tải lên: 21/01/2014, 18:20
Tài liệu Database Systems: The Complete Book- P12 docx
... instance, if the document has 1000 word occurrences, two of which are " ;database. " then the doculllent ~vould be placed at the ,002 coordinate in the dimension cor~esponding to " ;database. " ... unoccupied. then the "border" represents only a small addition to the volume of the cube (i.e., the number of tuples in the fact table). In that...
Ngày tải lên: 26/01/2014, 15:20
Tài liệu Database Systems: The Complete Book- P13 docx
... instance, if the document has 1000 word occurrences, two of which are " ;database. " then the doculllent ~vould be placed at the ,002 coordinate in the dimension cor~esponding to " ;database. " ... the data cube, the vie~vs we n-ould choose to materialize xi11 typically be aggregations of the full data cube. The coarser the partition implied by the gr...
Ngày tải lên: 26/01/2014, 15:20
Tài liệu Database Systems: The Complete Book- P5 pptx
... happens if there is a failure after line (14); perhaps the computer fails or the network connecting the database to the processor that is actually performing the transfer fails. Then the database ... seat and books it. The other customer's in- vocation then begins and sees that the seat is already occupied. It may matter to the customers who gets the seat, bu...
Ngày tải lên: 21/01/2014, 18:20