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I'm just at the begining of doing the SCJD assignment, and I have some confusion in processing the binary db file sun given.
The format of data in the database file is as follows:
Start of file 4 byte numeric, magic cookie value. Identifies this as a data file 2 byte numeric, number of fields in each record
Schema description section. Repeated for each field in a record: 1 byte numeric, length in bytes of field name n bytes(defined by previous entry), field name 1 byte numeric, field length in bytes end of repeating block
Data section. Repeat to end of file: 1 byte flag. 00 implies valid record, OxFF implies deleted record Record contaioning fields in order specified in schema section, no separators between fields, each field fixed length at maximum specified in schema information
End of file
All numeric values are stored in the header information use the formats of the DataInputStream and DataOutputStream classes. All text values, and all fields(which are text only), contain only 8 bit characters, null terminated if less than the maxmum length for the field. The character encoding is 8 bit US ASCII.
I'm not fimilar with Java IO, but I'm helped via many relatives threads in Java Ranch(so many thanks! ). I reslove the db file with some results:
1. the Start of file and the Schema section totally occupy 54 bytes 2. each record occupies 183 bytes 3. there're 33 records in the db file
But I don't know how to go the next step to process the db file, any advice ?
Thanks a lot !
SCJP 1.4<br />SCJD B&S(in progress)
Joined: Aug 02, 2005
Sorry for asking so strange question above...
Now I have dumped the whole data of the db file:
There's still a question ... The condition of the "for loop" is manully calculated. So stupid.... but How can I write in another smart way ??