dmartel@ireq.hydro.qc.ca (Denis Martel ETUDIANT SEPT 91) (06/11/91)
I have made a database program in C with BTRIEVE, but I need to translate BTR files into DBASE files. If there somebody know the structure of the header of a DBASE file ? Please E-mail. Thanks. /////////////////////////////////// Internet : dmartel@ireq.hydro.qc.ca ///////////////////////////////////
jmt@mullauna.cs.mu.OZ.AU (James Mark THOMAS) (06/12/91)
dmartel@ireq.hydro.qc.ca (Denis Martel ETUDIANT SEPT 91) writes: > I have made a database program in C with BTRIEVE, but I >need to translate BTR files into DBASE files. If there >somebody know the structure of the header of a DBASE file ? >Please E-mail. I am also interested, so if someone has this info, could they post it on line please? Thanks, Jim.
beacker@mips.com (Bradley Eacker) (06/13/91)
I am including the layout file that I ftp'd from chyde.uwasa.fi
earlier this year. I am not sure how the person involved collected
the data, though I have seen this same kind of data in the book
"PC File Formats" or something to that effect.
If anyone has been doing any kind of work to do a PD/shareware
version of the dbase interpreter, I would be interested in trying
to compare notes.
Just for the record, the opinions expressed here are
mine and should not reflect on anyone but me.
Brad Eacker (beacker@mips.com)
Database file structure
The structure of a dBASE III database file is composed of a header
and data records. The layout is given below.
dBASE III DATABASE FILE HEADER:
+---------+-------------------+---------------------------------+
| BYTE | CONTENTS | MEANING |
+---------+-------------------+---------------------------------+
| 0 | 1 byte | dBASE III version number |
| | | (03H without a .DBT file) |
| | | (83H with a .DBT file) |
+---------+-------------------+---------------------------------+
| 1-3 | 3 bytes | date of last update |
| | | (YY MM DD) in binary format |
+---------+-------------------+---------------------------------+
| 4-7 | 32 bit number | number of records in data file |
+---------+-------------------+---------------------------------+
| 8-9 | 16 bit number | length of header structure |
+---------+-------------------+---------------------------------+
| 10-11 | 16 bit number | length of the record |
+---------+-------------------+---------------------------------+
| 12-31 | 20 bytes | reserved bytes (version 1.00) |
+---------+-------------------+---------------------------------+
| 32-n | 32 bytes each | field descriptor array |
| | | (see below) | --+
+---------+-------------------+---------------------------------+ |
| n+1 | 1 byte | 0DH as the field terminator | |
+---------+-------------------+---------------------------------+ |
|
|
A FIELD DESCRIPTOR: <------------------------------------------+
+---------+-------------------+---------------------------------+
| BYTE | CONTENTS | MEANING |
+---------+-------------------+---------------------------------+
| 0-10 | 11 bytes | field name in ASCII zero-filled |
+---------+-------------------+---------------------------------+
| 11 | 1 byte | field type in ASCII |
| | | (C N L D or M) |
+---------+-------------------+---------------------------------+
| 12-15 | 32 bit number | field data address |
| | | (address is set in memory) |
+---------+-------------------+---------------------------------+
| 16 | 1 byte | field length in binary |
+---------+-------------------+---------------------------------+
| 17 | 1 byte | field decimal count in binary |
+---------+-------------------+---------------------------------+
| 18-31 | 14 bytes | reserved bytes (version 1.00) |
+---------+-------------------+---------------------------------+
The data records are layed out as follows:
1. Data records are preceeded by one byte that is a space (20H) if the
record is not deleted and an asterisk (2AH) if it is deleted.
2. Data fields are packed into records with no field separators or
record terminators.
3. Data types are stored in ASCII format as follows:
DATA TYPE DATA RECORD STORAGE
--------- --------------------------------------------
Character (ASCII characters)
Numeric - . 0 1 2 3 4 5 6 7 8 9
Logical ? Y y N n T t F f (? when not initialized)
Memo (10 digits representing a .DBT block number)
Date (8 digits in YYYYMMDD format, such as
19840704 for July 4, 1984)landers@vulcan.mgmt.purdue.edu (Chris Landers) (06/13/91)
The layout of a .dbf file is documented in Appendex D of Using dBase III+ Corrections noted below to the post are from page D-1 In article <4612@spim.mips.COM> beacker@mips.com (Bradley Eacker) writes: > >Database file structure > >The structure of a dBASE III database file is composed of a header >and data records. The layout is given below. > > >dBASE III DATABASE FILE HEADER: > >+---------+-------------------+---------------------------------+ >| BYTE | CONTENTS | MEANING | >+---------+-------------------+---------------------------------+ >| 0 | 1 byte | dBASE III version number | >| | | (03H without a .DBT file) | >| | | (83H with a .DBT file) | >+---------+-------------------+---------------------------------+ >| 1-3 | 3 bytes | date of last update | >| | | (YY MM DD) in binary format | >+---------+-------------------+---------------------------------+ yy mm dd in bianary format? the book only says: date of last update (yy mm dd) >| 4-7 | 32 bit number | number of records in data file | >+---------+-------------------+---------------------------------+ >| 8-9 | 16 bit number | length of header structure | >+---------+-------------------+---------------------------------+ >| 10-11 | 16 bit number | length of the record | >+---------+-------------------+---------------------------------+ number of bytes in the record >| 12-31 | 20 bytes | reserved bytes (version 1.00) | 12-14 3 bytes reserved bytes 15-27 13 bytes reserved for multi-user 28-31 20 bytes reserved bytes humm, my correction doesn't add up, but that's the book says, exactly as above. >+---------+-------------------+---------------------------------+ >| 32-n | 32 bytes each | field descriptor array | >| | | (see below) | --+ >+---------+-------------------+---------------------------------+ | >| n+1 | 1 byte | 0DH as the field terminator | | >+---------+-------------------+---------------------------------+ | > | > | >A FIELD DESCRIPTOR: <------------------------------------------+ > >+---------+-------------------+---------------------------------+ >| BYTE | CONTENTS | MEANING | >+---------+-------------------+---------------------------------+ >| 0-10 | 11 bytes | field name in ASCII zero-filled | >+---------+-------------------+---------------------------------+ >| 11 | 1 byte | field type in ASCII | >| | | (C N L D or M) | >+---------+-------------------+---------------------------------+ >| 12-15 | 32 bit number | field data address | >| | | (address is set in memory) | (not useful on disk) this third line added to the first two. >+---------+-------------------+---------------------------------+ >| 16 | 1 byte | field length in binary | >+---------+-------------------+---------------------------------+ >| 17 | 1 byte | field decimal count in binary | >+---------+-------------------+---------------------------------+ >| 18-31 | 14 bytes | reserved bytes (version 1.00) | >+---------+-------------------+---------------------------------+ 18-19 2 bytes reserved for multi-user 20 1 byte work area ID 21-22 2 bytes reserved for multi-user 23 1 byte SET FIELDS flag 24-31 8 bytes reserved bytes > > >The data records are layed out as follows: > > 1. Data records are preceeded by one byte that is a space (20H) if the > record is not deleted and an asterisk (2AH) if it is deleted. > > 2. Data fields are packed into records with no field separators or > record terminators. > > 3. Data types are stored in ASCII format as follows: > > DATA TYPE DATA RECORD STORAGE > --------- -------------------------------------------- > Character (ASCII characters) > Numeric - . 0 1 2 3 4 5 6 7 8 9 > Logical ? Y y N n T t F f (? when not initialized) > Memo (10 digits representing a .DBT block number) > Date (8 digits in YYYYMMDD format, such as > 19840704 for July 4, 1984) 4. The end-of-file marker is ans ASCII 26 (1AH) character. Structure of a database memo (.dbt) file is discussed on pages D-3 & D-4 I don't recall seeing this information in the Clipper Summer '87 manual, but it could be in one of the readme files. I don't know if it's found in the dBase IV manual because FLAME ON I don't own dBase IV, I don't plan to buy dBase IV, and I don't use dBase IV. I think this subject has been beat to death here! FLAME OFF Hope my corrections are helpful. -- <================================><===============================> || Christopher Landers || PURDUE UNIVERSITY - KRAN 708 || || Krannert Computing Center || West Lafayette, IN 47907 || <=================== landers@zeus.mgmt.purdue.edu ================>
tomr@dbase.a-t.com (Tom Rombouts) (06/18/91)
In article <1991Jun12.224335.7552@vulcan.mgmt.purdue.edu> landers@vulcan.mgmt.purdue.edu (Chris Landers) writes: [description of .DBF file format w/corrections deleted] >I don't know if it's found in the dBase IV manual because >FLAME ON >I don't own dBase IV, I don't plan to buy dBase IV, and I don't use dBase IV. >I think this subject has been beat to death here! >FLAME OFF Yes, it is in the dBASE IV manual, appendix E in the 1.1 Language Reference Manual. (Note that some features, such as "F" data type fields, are new with dBASE IV.) If you really want to get into it, there are at least four third-party C libraries available with source to create or manipulate .DBF files with various degrees of .DBT, .NDX, .MDX and .NTX support, depending on the specific library. Tom Rombouts Torrance 'Tater tomr@ashtate.A-T.com