通过PHP读取dbf数据

【转帖】通过PHP读取dbf数据（visual fox pro，VFP数据库），官方的dbase无法读取字段为类型memo的数据，国外网站的解决方案 How to read FoxPro Memo with PHP?

原帖为英文，地址： http://stackoverflow.com/questions/1947348/how-to-read-foxpro-memo-with-php

测试可正常读取memory数据，特转帖供有需要的同学参考，并向原作者致谢！

以下仅将内容粘贴过来，并未整理。
How to read FoxPro Memo with PHP?

I have to convert .DBF and .FPT files from Visual FoxPro to MySQL. Right now my script works for .DBF files, it opens and reads them with dbase_open() and dbase_get_record_with_names() and then executes the MySQL INSERT commands.

However, some fields of these .DBF files are of type MEMO and therefore stored in a separate files ending in .FPT. How do I read this file?

I have found the specifications of this filetype in MSDN, but I don't know how I can read this file byte-wise with PHP (also, I would really prefer a simplier solution).

Any ideas?

Alright, I have carefully studied the MSDN specifications of DBF and FPT file structures and the outcome is a beautiful PHP class which can open a DBF and (optional) an FPT memo file at the same time. This class will give you record after record and thereby fetch any memos from the memo file - if opened.
```
  1 class Prodigy_DBF {
  2     private $Filename, $DB_Type, $DB_Update, $DB_Records, $DB_FirstData, $DB_RecordLength, $DB_Flags, $DB_CodePageMark, $DB_Fields, $FileHandle, $FileOpened;
  3     private $Memo_Handle, $Memo_Opened, $Memo_BlockSize;
  4
  5     private function Initialize() {
  6
  7         if($this->FileOpened) {
  8             fclose($this->FileHandle);
  9         }
 10
 11         if($this->Memo_Opened) {
 12             fclose($this->Memo_Handle);
 13         }
 14
 15         $this->FileOpened = false;
 16         $this->FileHandle = NULL;
 17         $this->Filename = NULL;
 18         $this->DB_Type = NULL;
 19         $this->DB_Update = NULL;
 20         $this->DB_Records = NULL;
 21         $this->DB_FirstData = NULL;
 22         $this->DB_RecordLength = NULL;
 23         $this->DB_CodePageMark = NULL;
 24         $this->DB_Flags = NULL;
 25         $this->DB_Fields = array();
 26
 27         $this->Memo_Handle = NULL;
 28         $this->Memo_Opened = false;
 29         $this->Memo_BlockSize = NULL;
 30     }
 31
 32     public function __construct($Filename, $MemoFilename = NULL) {
 33         $this->Prodigy_DBF($Filename, $MemoFilename);
 34     }
 35
 36     public function Prodigy_DBF($Filename, $MemoFilename = NULL) {
 37         $this->Initialize();
 38         $this->OpenDatabase($Filename, $MemoFilename);
 39     }
 40
 41     public function OpenDatabase($Filename, $MemoFilename = NULL) {
 42         $Return = false;
 43         $this->Initialize();
 44
 45         $this->FileHandle = fopen($Filename, "r");
 46         if($this->FileHandle) {
 47             // DB Open, reading headers
 48             $this->DB_Type = dechex(ord(fread($this->FileHandle, 1)));
 49             $LUPD = fread($this->FileHandle, 3);
 50             $this->DB_Update = ord($LUPD[0])."/".ord($LUPD[1])."/".ord($LUPD[2]);
 51             $Rec = unpack("V", fread($this->FileHandle, 4));
 52             $this->DB_Records = $Rec[1];
 53             $Pos = fread($this->FileHandle, 2);
 54             $this->DB_FirstData = (ord($Pos[0]) + ord($Pos[1]) * 256);
 55             $Len = fread($this->FileHandle, 2);
 56             $this->DB_RecordLength = (ord($Len[0]) + ord($Len[1]) * 256);
 57             fseek($this->FileHandle, 28); // Ignoring "reserved" bytes, jumping to table flags
 58             $this->DB_Flags = dechex(ord(fread($this->FileHandle, 1)));
 59             $this->DB_CodePageMark = ord(fread($this->FileHandle, 1));
 60             fseek($this->FileHandle, 2, SEEK_CUR);    // Ignoring next 2 "reserved" bytes
 61
 62             // Now reading field captions and attributes
 63             while(!feof($this->FileHandle)) {
 64
 65                 // Checking for end of header
 66                 if(ord(fread($this->FileHandle, 1)) == 13) {
 67                     break;  // End of header!
 68                 } else {
 69                     // Go back
 70                     fseek($this->FileHandle, -1, SEEK_CUR);
 71                 }
 72
 73                 $Field["Name"] = trim(fread($this->FileHandle, 11));
 74                 $Field["Type"] = fread($this->FileHandle, 1);
 75                 fseek($this->FileHandle, 4, SEEK_CUR);  // Skipping attribute "displacement"
 76                 $Field["Size"] = ord(fread($this->FileHandle, 1));
 77                 fseek($this->FileHandle, 15, SEEK_CUR); // Skipping any remaining attributes
 78                 $this->DB_Fields[] = $Field;
 79             }
 80
 81             // Setting file pointer to the first record
 82             fseek($this->FileHandle, $this->DB_FirstData);
 83
 84             $this->FileOpened = true;
 85
 86             // Open memo file, if exists
 87             if(!empty($MemoFilename) and file_exists($MemoFilename) and preg_match("%^(.+).fpt$%i", $MemoFilename)) {
 88                 $this->Memo_Handle = fopen($MemoFilename, "r");
 89                 if($this->Memo_Handle) {
 90                     $this->Memo_Opened = true;
 91
 92                     // Getting block size
 93                     fseek($this->Memo_Handle, 6);
 94                     $Data = unpack("n", fread($this->Memo_Handle, 2));
 95                     $this->Memo_BlockSize = $Data[1];
 96                 }
 97             }
 98         }
 99
100         return $Return;
101     }
102
103     public function GetNextRecord($FieldCaptions = false) {
104         $Return = NULL;
105         $Record = array();
106
107         if(!$this->FileOpened) {
108             $Return = false;
109         } elseif(feof($this->FileHandle)) {
110             $Return = NULL;
111         } else {
112             // File open and not EOF
113             fseek($this->FileHandle, 1, SEEK_CUR);  // Ignoring DELETE flag
114             foreach($this->DB_Fields as $Field) {
115                 $RawData = fread($this->FileHandle, $Field["Size"]);
116                 // Checking for memo reference
117                 if($Field["Type"] == "M" and $Field["Size"] == 4 and !empty($RawData)) {
118                     // Binary Memo reference
119                     $Memo_BO = unpack("V", $RawData);
120                     if($this->Memo_Opened and $Memo_BO != 0) {
121                         fseek($this->Memo_Handle, $Memo_BO[1] * $this->Memo_BlockSize);
122                         $Type = unpack("N", fread($this->Memo_Handle, 4));
123                         if($Type[1] == "1") {
124                             $Len = unpack("N", fread($this->Memo_Handle, 4));
125                             $Value = trim(fread($this->Memo_Handle, $Len[1]));
126                         } else {
127                             // Pictures will not be shown
128                             $Value = "{BINARY_PICTURE}";
129                         }
130                     } else {
131                         $Value = "{NO_MEMO_FILE_OPEN}";
132                     }
133                 } else {
134                     $Value = trim($RawData);
135                 }
136
137                 if($FieldCaptions) {
138                     $Record[$Field["Name"]] = $Value;
139                 } else {
140                     $Record[] = $Value;
141                 }
142             }
143
144             $Return = $Record;
145         }
146
147         return $Return;
148     }
149
150     function __destruct() {
151         // Cleanly close any open files before destruction
152         $this->Initialize();
153     }
154 }
```

The class can be used like this:
```
1 $Test = new Prodigy_DBF("customer.DBF", "customer.FPT");
2 while(($Record = $Test->GetNextRecord(true)) and !empty($Record)) {
3     print_r($Record);
4 }
```

It might not be an almighty perfect class, but it works for me. Feel free to use this code, but note that the class is VERY tolerant - it doesn't care if fread() and fseek() return true or anything else - so you might want to improve it a bit before using.

Also note that there are many private variables like number of records, recordsize etc. which are not used at the moment.

moper辛勤播种的土地我是个蒸不烂、煮不熟、捶不扁、炒不爆、响珰珰一粒铜豌豆

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