Fujitsu UDS/SQL V2.5 사용자 설명서
Structure of pages
Data page
U929-J-Z125-9-76
215
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1
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24 V
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20
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20
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18
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7
7.7 Data page
Depending on which page length was defined for the database, the length of a data page
may be 2048 bytes, 4000 bytes or 8096 bytes.
may be 2048 bytes, 4000 bytes or 8096 bytes.
Data pages with a length of 2048 bytes differ from those consisting of 4000 or 8096 bytes
with respect to the lengths of entries for the database key value and the page index:
with respect to the lengths of entries for the database key value and the page index:
–
In the case of data pages with a length of 2048 bytes, the entry for the database key
value is 4 bytes in length and that of the page index entry is 8 bytes.
value is 4 bytes in length and that of the page index entry is 8 bytes.
–
For data pages with a length of 4000 or 8096 bytes, the entry for the database key value
is 8 bytes in length and that of the page index entry is 12 bytes.
is 8 bytes in length and that of the page index entry is 12 bytes.
The following data may be placed in a data page:
–
pointer arrays
–
lists
–
sort key tables
–
SEARCH key tables
–
records that are not stored in a hash area
The values given in the form “number1/number2“ (e.g. 25/29) in
must be inter-
preted as follows:
–
“number1” indicates the applicable value for data pages with a length of 2048 bytes.
–
“number2” indicates the applicable value for data pages with a length of 4000 or 8096
bytes.
bytes.
All other length and displacement entries are equally applicable to data pages with a length
of 2048 bytes and those with a length of 4000 or 8096 bytes.
of 2048 bytes and those with a length of 4000 or 8096 bytes.