A client database or DBC file is a simple binary format for a database table.

Each record in the file is one row of the table. Field values may consist of a limited range of data types, and do not include field separation characters
- except for character-based string fields.

DBC files nearly always use file extension DBC (or dbc) and DB2 (or db2) and have been named DataBaseClient files ever since their discovery in the DataBaseClient folder in the client files. The true extension meaning has not yet been revealed by Blizzard.

Technical details

Each file consists of a header, the table data, and if necessary a string block.

Header

00h: char[4] Signature always 'WDBC'
04h: int32 Records number of records in the file
08h: int32 Fields number of fields per record
0Ch: int32 Record Size Fields*FieldSize (FieldSize is usually 4, but not always)
10h: int32 String Block Size Size of the string block

Table Data

Each record has a constant length. Usually all the values are 32bit integers. String data is stored in a block after the records. String data in records contain an offset to the string, relative to the start of the string block.

When encountering string data, it usually consists of an English name field, followed by 7 additional fields for different localizations.

String Block

A continuous block of zero-terminated strings. Offsets into the String Block are relative to the start of the block.

A more detailed breakdown follows:

DBC file layout

The DBC file layout is fairly simple, below is a hex display of the file AuctionHouse.dbc

Header Block

The first section is the header block which is 20 bytes long

57 44 42 43 is the filetype is text. Normally "WDBC" or "WDB2"

07 00 00 00 is the number of rows, the byte order is reversed, so this would be 00 00 00 07 = 7 Rows of data.

0d 00 00 00 is the number of fields, again byte order reversed, so 00 00 00 0d = 13 rows of data

34 00 00 00 is the length of the row 00 00 00 34 = 52 bytes long

aa 00 00 00 is the length of the string block

The start of the string block can be calculated one of two ways:

• The length of the file - the size of the string block
• The length of the header + (number of rows * length of the row)

Using the latter approach, we can calculate the start of the string block as follows:

The length of the header + (number of rows * length of the row) i.e. 20 + (7 * 52) = 384 (or 180 in hex).

This gives us the start offset for the string block 00000180h

Data Block

The Second section is the data block, from the values obtained above from the header we know there are 7 records and 13 fields. Each field is typically 4 bytes long.

Here is the first record:

All the byte groups are in reverse order as before

01 00 00 00 is 00 00 00 01 = 1,

01 00 00 00 is 00 00 00 01 = 1,

05 00 00 00 is 00 00 00 05 = 5,

05 00 00 00 is 00 00 00 05 = 5,

01 00 00 00 is 00 00 00 01 = 1, is the string offset for the text

00 00 00 00 is 00 00 00 00 = 0, same for localised languages

00 00 00 00 is 00 00 00 00 = 0, same for localised languages

00 00 00 00 is 00 00 00 00 = 0, same for localised languages

00 00 00 00 is 00 00 00 00 = 0, same for localised languages

00 00 00 00 is 00 00 00 00 = 0, same for localised languages

00 00 00 00 is 00 00 00 00 = 0, same for localised languages

00 00 00 00 is 00 00 00 00 = 0, same for localised languages

7e 00 3f 00 is 00 3f 00 7e = 4128894

If you check out the Wiki page for AuctionHouse.dbc you will see that we have the fields:

AuctionHouse ID = 1
Faction ID =1
Auction Fee = 5
Deposit Tax = 5
Name = 1
Name1 = 0
Name2 = 0
Name3 = 0
Name4 = 0
Name5 = 0
Name6 = 0
Name7 = 0
Text Checksum = 4128894

String Block

The string block is a chunk of text strings, separated by nulls.

Now previously we had calculated the start offset for the string block as 00000180h

As we saw above, the Value for Name was 1, add this is the base gives 181h, then read all characters until a null. This is the start character of "Stormwind Auction House" (there is a null after "House").

Looking at all the records, the string offsets are:

01h = 1 - "Stormwind Auction House"
19h = 25 - "Alliance Auction House"
30h = 48 - "Darnassus Auction House"
48h = 72 - "Undercity Auction House"
60h = 96 - "Thunder Bluff Auction House"
7dh = 125 - "Horde Auction House"
91h = 145 - "Blackwater Auction House"