Perl: Data Persistence
DBM files |
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This unit presents enough principles to access to
Berkeley DB
from Perl, using the DB_File module. The base work is done on top of DBM files,
which are on-disk hash tables. And, being hash tables, you can
look up values by key and update and delete values in place.
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| ODBM | the length of a key, plus the length of its associated
value, may not exceed 1008 bytes. |
SDBM,
NDBM |
may have a default limit of 1024 bytes for the size of a record. |
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| Fcntl constants |
O_RDONLY Read only
O_WRONLY Write only
O_RDWR Read and write
O_CREAT Create the file if it doesn't exist
O_EXCL Fail if the file already exists
O_APPEND Append to the file
O_TRUNC Truncate the file
O_NONBLOCK Non-blocking access
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