What Is a DBF File? Find the Family, Then Open or Convert It

2 Which Kind of DBF File Is Yours? The first byte names the family

You need no special software. The short script below prints the version byte, the record count, the size check and the field list for any DBF file. Save it as check_dbf.py and give it the name of your DBF file.

import struct, sys
NAMES = {
    0x02: "FoxBASE",
    0x03: "dBASE III or FoxBASE+, no memo",
    0x30: "Visual FoxPro",
    0x31: "Visual FoxPro, autoincrement",
    0x32: "Visual FoxPro, varchar",
    0x43: "dBASE IV SQL table",
    0x63: "dBASE IV SQL system",
    0x83: "dBASE III with memo",
    0x8B: "dBASE IV with memo",
    0xCB: "dBASE IV SQL table with memo",
    0xF5: "FoxPro 2.x with memo",
    0xFB: "FoxBASE",
}
data = open(sys.argv[1], "rb").read()
if len(data) < 32:
    sys.exit("Too short for a DBF header")
ver = data[0]
count, hlen, rlen = struct.unpack("<IHH", data[4:12])
print("Version byte: %02x = %s" % (ver, NAMES.get(ver, "not on the common lists")))
print("Update bytes (year, month, day): %d %d %d" % (data[1], data[2], data[3]))
print("Records: %d. Header: %d bytes. Record: %d bytes." % (count, hlen, rlen))
print("Table flags: %d. Code page byte: %d." % (data[28], data[29]))
print("File size: %d bytes. Header math needs %d." % (len(data), hlen + count * rlen))
for i in range(32, hlen - 1, 32):
    d = data[i:i + 32]
    if len(d) < 32 or d[0] == 0x0D:
        break
    name = d[:11].split(b"\0")[0].decode("ascii", "replace")
    print("Field %s, type %s, length %d, decimals %d" % (name, chr(d[11]), d[16], d[17]))

python check_dbf.py people.dbf
Version byte: 03 = dBASE III or FoxBASE+, no memo
Update bytes (year, month, day): 114 8 2
Records: 3. Header: 97 bytes. Record: 25 bytes.
Table flags: 0. Code page byte: 0.
File size: 173 bytes. Header math needs 172.
Field NAME, type C, length 16, decimals 0
Field BIRTHDATE, type D, length 8, decimals 0

We tried the script on all 136 public files. It named the version for 129 of them. For 6 it said the byte is not on the lists we checked, and one DBF file was too short to read a header. The table shows the kinds in our set, with how many opened in LibreOffice and in all four readers.

Three more clues about your DBF file

3 What Is Inside DBF Files? A header, a field list and fixed-width rows

Think of a printed ledger. The cover says how many pages there are. The first page lists the columns. Then comes row after row, every row the same width. A DBF file is built the same way, and the header records the size of every part.

This follows Microsoft's Visual FoxPro description. It says the record length includes the delete flag. It says the field list ends with the byte 0d and that a field name can have at most 10 characters. The flags byte can add up too: 3 means the table has a structural .cdx index and a memo field.

The field list and the delete flag

Every field entry has the name, a type letter, a length and a count of decimal places. In our DBF file, NAME was type C with length 20 and QTY was type N with length 5. PRICE was type N with length 8 and 2 decimals. ADDED was type D and PAID was type L. The type letters are C for text, N for numbers, D for dates and L for yes or no.

Records start with one flag byte. A space (20) means the record is live, and an asterisk (2a) means it was deleted, says Microsoft. Deleting a row can mean only setting that flag. In our DBF file the text Delete me was still there after the asterisk. The DBF file showed 2 rows in LibreOffice and dbfread and 3 in the dbf library, which keeps deleted rows and marks them.

How a record looks as plain text

In our first record the bytes spelled out as the name Pencil padded with spaces, the number 100, the price 0.35, the date 20260105 and the letter T. Numbers and dates are stored as text. That is why many DBF files stay readable in a text editor, as the next test shows.

12 What Else Uses the DBF Ending? Shapefile tables, FoxPro tables and other relatives

Many programs share the .dbf ending. The format began in dBASE, and Wikipedia's dBase article names Clipper, FoxPro and VP-Info among the products that use it, with the open-source Harbour, xHarbour and Clip. It warns that not all variants are compatible.

The .dbf file next to a .shp file

A map download often has three files with one name: .shp, .shx and .dbf. Wikipedia's shapefile article calls all three mandatory and says the .dbf file stores the attributes of every shape in dBase IV format. A .shp file alone is incomplete.

The same article gives limits: field names of at most 10 characters, up to 255 fields and text of up to 254 characters. It says a .cpg file names the code page, because Unicode support is poor. So a shapefile table follows the letters advice too. Two of our four test projects, GDAL and pyshp, work with map data.

A DBF file is not an Access file

A DBF file is one table. An Access database can have many tables, queries and forms in one DBF file, and it ends in .mdb or .accdb. If a program says your DBF file is not a database, you may have the wrong ending. Read the first byte before you rename anything.

13 What Is the DBF File Format Made Of? The header facts, and what we could check

About version bytes outside the list

Microsoft lists the version bytes 02, 03, 30, 43, 63, 83, 8b, cb, f5 and fb. The dbf2002 page adds 31, 32 and e5. Our public files also had 8c, 90 and 04. One DBF file with 8c is named dbase_7, but we found no document to confirm what the other two bytes mean, so we do not guess.

LibreOffice refused all six of those files. dbfread opened one of the six and pyshp opened two, so a strict reader is not always the right one. The facts table lists only what we could check.

What we left out

We did not test Excel, Access, dBASE, Visual FoxPro, DBF Viewer 2000, a GIS program, Windows or a Mac. We did not test the LibreOffice desktop window either. Our results come from its command-line converter, version 24.2.7, and the desktop import dialog may offer more choices.

We had no index files, so we cannot say how any reader treats a missing .cdx or .ndx. We had no file made by dBASE or FoxPro. Our own files came from the dbf Python library. We did not read the dBASE 7 specification.

We did not test the SysTools or Freeviewer viewers. What we say about them comes from their pages. We name no prices, because the pages gave none we could check.

Sources checked

For the header and fields, see Microsoft's table file structure page. For version bytes beyond Microsoft's list, see the version byte list on dbf2002. For the memo files, see the SAS note on memo files and the Microsoft file extensions page.

For history and status, see the Library of Congress DBF record and the Wikipedia entry on dBase. For Excel, see Microsoft's list of supported Excel formats. For maps, see the Wikipedia entry on shapefiles. Every test count came from the 157 files and the scripts in our research folder.