• Python 读取DBF/FPT 文件
  • FPT 文件格式
  • Python DBF模块
    • DBF.PY
    • dbfpy

Python 读取DBF/FPT 文件

DBF/FPT是 FoxPro 数据库存储文件的格式，虽然现在 FoxPro 已经不用了，但是有些情况下我们需要读取DBF/FPT数据库文件。这里整理了用Python读取DBF/FPT文件相关 Python 模块。

FPT 文件格式

FPT文件是FoxPro存储备注信息的文件。

The file format is used by Fox Pro 2.x and later The size of the header is 512 bytes           _______________________  _______00h /   0 | Number of next        |  ^00h /   1 | available block       |  |00h /   2 | for appending data    | Header00h /   3 | (binary)            *1|  |          |-----------------------|  |00h /   4 | ( Reserved )          |  |00h /   5 |                       |  |          |-----------------------|  |00h /   6 | Size of blocks N    *1|  |00h /   7 |                     *2|  |          |-----------------------|  |00h /   8 | ( Reserved )          |  |          |                       |  |          |                       |  |          | (i.e. garbage)        |  |          :                       :  |          :                       :  |00h /  511|                       |  |          |=======================| _v_____00h /    0|                       |  ^                 Used block          |                       |  |           __  |=======================|          |                       |  |          /   0| Record type         *3|          :                       :  |         /    1|                     *1|          :                       :  |        /     2|                       |          |                       |  |       /      3|                       |00h /    N|                       |  |      /        |-----------------------|          |=======================| _|_____/        4| Length of memo field  |00h /    0|                       |  |              5|                     *1|          :                       :  |              6|                       |          :                       :  |              7|                       |          |                       |  |               |-----------------------|00h /    N|                       | _|_____         8| Memo data             |          |=======================|  |     \         :                       :         0|                       |  |      \       N|                       |          |                       |  |       \_____  |=======================|          |                       |  |          :                       :  |00h /    N|                       | _v_____          |=======================|

1. Big-endian. Binary value with high byte first.
2. Size of blocks in memo file (SET BLOCKSIZE). Default is 512 bytes.
3. Record type

Value  Description00h Picture. This normally indicates that file is produced on a MacIntosh, since pictures on the DOS/Windows platform are "objects".01h Memo02h Object

A memo field can be longer than the 512 byte block. It simply continues through the next block. The field is logically terminated by two End-of-file marks in the field. The reminder of the block is unused.

Python DBF模块

DBF.PY

• http://www.physics.ox.ac.uk/users/santoso/dbf.py.src

"""This is a DBF reader which reads Visual Fox Pro DBF format with Memo field. Usage:    rec = readDbf('test.dbf')    for line in rec:        print line['name'] @author Yusdi Santoso@date 13/07/2007"""import structimport os, os.pathimport sysimport csvimport tempfileimport ConfigParser class Dbase:    def __init__(self):        self.fdb = None        self.fmemo = None        self.db_data = None        self.memo_data = None        self.fields = None        self.num_records = 0        self.header = None        self.memo_file = ''        self.memo_header = None        self.memo_block_size = 0        self.memo_header_len = 0     def _drop_after_NULL(self, txt):        for i in range(0, len(txt)):            if ord(struct.unpack('c', txt[i])[0])==0:                return txt[:i]        return txt      def _reverse_endian(self, num):        if not len(num):            return 0        val = struct.unpack('L', val[0])        val = struct.unpack('>L', val)        return val[0]     def _assign_ids(self, lst, ids):        result = {}        idx = 0        for item in lst:            id = ids[idx]            result[id] = item            idx += 1        return result     def open(self, db_name):        filesize = os.path.getsize(db_name)        if filesize <= 68:            raise IOError, 'The file is not large enough to be a dbf file'         self.fdb = open(db_name, 'rb')         self.memo_file = ''        if os.path.isfile(db_name[0:-1] + 't'):            self.memo_file = db_name[0:-1] + 't'        elif os.path.isfile(db_name[0:-3] + 'fpt'):            self.memo_file = db_name[0:-3] + 'fpt'         if self.memo_file:                #Read memo file            self.fmemo = open(self.memo_file, 'rb')            self.memo_data = self.fmemo.read()            self.memo_header = self._assign_ids(struct.unpack('>6x1H', self.memo_data[:8]), ['Block size'])            block_size = self.memo_header['Block size']            if not block_size:                block_size = 512            self.memo_block_size = block_size            self.memo_header_len = block_size            memo_size = os.path.getsize(self.memo_file)         #Start reading data file        data = self.fdb.read(32)        self.header = self._assign_ids(struct.unpack(' self.num_records:            raise Exception, 'Unable to extract data outside the range'          offset = self.header['Record Size'] * rec_no        data = self.db_data[offset:offset+self.row_len]        record = self._assign_ids(struct.unpack(self.row_format, data), self.row_ids)         if self.memo_file:            for key in self.fields:                field = self.fields[key]                f_type = field['Field Type']                f_name = field['Field Name']                c_data = record[f_name]                 if f_type=='M' or f_type=='G' or f_type=='B' or f_type=='P':                    c_data = self._reverse_endian(c_data)                    if c_data:                        record[f_name] = self.read_memo(c_data-1).strip()                else:                    record[f_name] = c_data.strip()        return record     def read_memo_record(self, num, in_length):        """        Read the record of given number. The second parameter is the length of        the record to read. It can be undefined, meaning read the whole record,        and it can be negative, meaning at most the length        """        if in_length < 0:            in_length = -self.memo_block_size         offset = self.memo_header_len + num * self.memo_block_size        self.fmemo.seek(offset)        if in_length<0:            in_length = -in_length        if in_length==0:            return ''        return self.fmemo.read(in_length)         def read_memo(self, num):        result = ''        buffer = self.read_memo_record(num, -1)        if len(buffer)<=0:            return ''        length = struct.unpack('>L', buffer[4:4+4])[0] + 8         block_size = self.memo_block_size        if length < block_size:            return buffer[8:length]        rest_length = length - block_size        rest_data = self.read_memo_record(num+1, rest_length)        if len(rest_data)<=0:            return ''        return buffer[8:] + rest_data def readDbf(filename):    """    Read the DBF file specified by the filename and     return the records as a list of dictionary.    @param filename File name of the DBF    @return List of rows    """    db = Dbase()    db.open(filename)    num = db.get_numrecords()    rec = []    for i in range(0, num):        record = db.get_record_with_names(i)        rec.append(record)        db.close()    return  rec if __name__=='__main__':    rec = readDbf('dbf/sptable.dbf')    for line in rec:        print '%s %s' % (line['GENUS'].strip(), line['SPECIES'].strip())

dbfpy

• http://sourceforge.net/projects/dbfpy/