Package dbf
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Source Code for Package dbf

  1  """ 
  2  Copyright 
  3  ========= 
  4      - Copyright: 2008-2009 Ad-Mail, Inc -- All rights reserved. 
  5      - Author: Ethan Furman 
  6      - Contact: ethanf@admailinc.com 
  7      - Organization: Ad-Mail, Inc. 
  8      - Version: 0.85.005 as of 29 Oct 2009 
  9   
 10  Redistribution and use in source and binary forms, with or without 
 11  modification, are permitted provided that the following conditions are met: 
 12      - Redistributions of source code must retain the above copyright 
 13        notice, this list of conditions and the following disclaimer. 
 14      - Redistributions in binary form must reproduce the above copyright 
 15        notice, this list of conditions and the following disclaimer in the 
 16        documentation and/or other materials provided with the distribution. 
 17      - Neither the name of Ad-Mail, Inc nor the 
 18        names of its contributors may be used to endorse or promote products 
 19        derived from this software without specific prior written permission. 
 20   
 21  THIS SOFTWARE IS PROVIDED BY Ad-Mail, Inc ''AS IS'' AND ANY 
 22  EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
 23  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
 24  DISCLAIMED. IN NO EVENT SHALL Ad-Mail, Inc BE LIABLE FOR ANY 
 25  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 
 26  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 
 27  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 
 28  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
 29  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
 30  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 31   
 32  B{I{Summary}} 
 33   
 34  Python package for reading/writing dBase III and VFP 6 tables and memos 
 35   
 36  The entire table is read into memory, and all operations occur on the in-memory 
 37  table, with data changes being written to disk as they occur. 
 38   
 39  Goals:  programming style with databases 
 40      - C{table = dbf.table('table name' [, fielddesc[, fielddesc[, ....]]])} 
 41          - fielddesc examples:  C{name C(30); age N(3,0); wisdom M; marriage D} 
 42      - C{record = [ table.current() | table[int] | table.append() | table.[next|prev|top|bottom|goto]() ]} 
 43      - C{record.field | record['field']} accesses the field 
 44   
 45  NOTE:  Of the VFP data types, auto-increment and null settings are not implemented. 
 46  """ 
 47  import os 
 48   
 49  from dbf.dates import Date, DateTime, Time 
 50  from dbf.exceptions import DbfWarning, Bof, Eof, DbfError, DataOverflow, FieldMissing 
 51  from dbf.tables import DbfTable, Db3Table, VfpTable, DbfList, DbfCsv, version_map 
 52   
 53  version = (0, 86, 0) 
 54   
 55  __docformat__ = 'epytext' 
 56   
57 -def Table(filename, field_spec='', memo_size=128, ignore_memos=False, \ 58 read_only=False, keep_memos=False, meta_only=False, type='db3', codepage=None):
59 "returns an open table of the correct type, or creates it if field_spec is given" 60 type = type.lower() 61 if field_spec: 62 if type == 'db3': 63 return Db3Table(filename, field_spec, memo_size, ignore_memos) 64 elif type == 'vfp': 65 return VfpTable(filename, field_spec, memo_size, ignore_memos) 66 elif type == 'dbf': 67 return DbfTable(filename, field_spec) 68 else: 69 raise TypeError("Unknown table type: %s" % type) 70 else: 71 base, ext = os.path.splitext(filename) 72 if ext == '': 73 filename = base + '.dbf' 74 if not os.path.exists(filename): 75 raise DbfError("File %s not found, field_spec not specified" % filename) 76 fd = open(filename) 77 version = fd.read(1) 78 fd.close() 79 fd = None 80 if not version in version_map: 81 raise TypeError("Unknown dbf type: %x" % ord(version)) 82 for tabletype in (Db3Table, VfpTable): 83 if version in tabletype._supported_tables: 84 return tabletype(filename, field_spec, memo_size, ignore_memos, \ 85 read_only, keep_memos, meta_only) 86 else: 87 raise TypeError("Tables of type <%s [%x]> are not supported." % (version_map.get(version, 'Unknown: %s' % version), ord(version)))
88 -def table_type(filename):
89 "returns text representation of a table's dbf version" 90 base, ext = os.path.splitext(filename) 91 if ext == '': 92 filename = base + '.dbf' 93 if os.path.exists(filename): 94 fd = open(filename) 95 version = fd.read(1) 96 fd.close() 97 fd = None 98 if not version in version_map: 99 raise TypeError("Unknown dbf type: %s (%x)" % (version, ord(version))) 100 return version_map[version] 101 return 'File %s not found' % filename
102 -def add_fields(table, field_spec):
103 "adds fields to an existing table" 104 table = Table(table) 105 try: 106 table.add_fields(field_spec) 107 finally: 108 table.close()
109 -def delete_fields(table, field_names):
110 "deletes fields from an existing table" 111 table = Table(table) 112 try: 113 table.delete_fields(field_names) 114 finally: 115 table.close()
116 -def export(table, filename='', fields='', format='csv', header=True):
117 "creates a csv or tab-delimited file from an existing table" 118 table = Table(table) 119 try: 120 table.export(filename, fields, format, header) 121 finally: 122 table.close()
123 -def first_record(table):
124 "prints the first record of a table" 125 table = Table(table) 126 try: 127 print str(table[0]) 128 finally: 129 table.close()
130 -def from_csv(csvfile, to_disk=False, filename=None, field_names=None):
131 "creates a Character table from a csv file" 132 reader = csv.reader(open(csvfile)) 133 if field_names is None: 134 field_names = ['f0'] 135 else: 136 field_names = field_names.replace(', ',',').split(',') 137 mtable = Table(':memory:', '%s M' % field_names[0]) 138 field_count = 1 139 for row in reader: 140 while field_count < len(row): 141 if field_count == len(field_names): 142 field_names.append('f%d' % field_count) 143 mtable.add_fields('%s M' % field_names[field_count]) 144 field_count += 1 145 mtable.append(tuple(row)) 146 if to_disk: 147 if filename is None: 148 filename = os.path.splitext(csvfile)[0] 149 length = [1] * field_count 150 for record in mtable: 151 for i in range(field_count): 152 length[i] = max(length[i], len(record[i])) 153 fields = mtable.field_names 154 fielddef = [] 155 for i in range(field_count): 156 if length[i] < 255: 157 fielddef.append('%s C(%d)' % (fields[i], length[i])) 158 else: 159 fielddef.append('%s M' % (fields[i])) 160 csvtable = Table(filename, ','.join(fielddef)) 161 for record in mtable: 162 csvtable.append(record.scatter_fields()) 163 return mtable
164 -def get_fields(table):
165 "returns the list of field names of a table" 166 table = Table(table) 167 return table.field_names
168 -def info(table):
169 "prints table info" 170 table = Table(table) 171 print str(table)
172 -def rename_field(table, oldfield, newfield):
173 "renames a field in a table" 174 table = Table(table) 175 try: 176 table.rename_field(oldfield, newfield) 177 finally: 178 table.close()
179 -def structure(table, field=None):
180 "returns the definition of a field (or all fields)" 181 table = Table(table) 182 return table.structure(field)
183 -def hex_dump(records):
184 "just what it says ;)" 185 for index,dummy in enumerate(records): 186 chars = dummy._data 187 print "%2d: " % index, 188 for char in chars[1:]: 189 print " %2x " % ord(char), 190 print
191