book.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
 
<book xml:id="book.dbase" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
 <?phpdoc extension-membership="pecl" ?>
 <title>dBase</title>
 
 <!-- {{{ preface -->
 <preface xml:id="intro.dbase">
  &reftitle.intro;
  <note>
   <para>
    &pecl.moved-ver;5.3.0.
   </para>
  </note>
  <para>
   These functions allow you to access records stored in dBase-format
   (dbf) databases.
  </para>
  <warning>
   <para>
    We recommend against using dBase files as your production
    database. Use <link xlink:href="&url.sqlite;">SQLite</link> or choose any real SQL server instead; <link 
    xlink:href="&url.mysql;">MySQL</link> or <link xlink:href="&url.pgsql;">Postgres</link>
    are common choices with PHP. dBase support is here to allow you to
    import and export data to and from your web database, because the
    file format is commonly understood by Windows spreadsheets and
    organizers.
   </para>
  </warning>
  <caution>
   <para>
    As of dbase 7.0.0 the databases are automatically locked via
    <function>flock</function>. There has been no support for locking earlier,
    so two concurrent web server processes modifying the same dBase file would
    have very likely ruined your database. This can happen even with dbase
    7.0.0+ on systems which implement the locks at the process level with
    multithreaded SAPIs.
   </para>
  </caution>
  <para>
   dBase files are simple sequential files of fixed length records. 
   Records are appended to the end of the file and deleted records are
   kept until you call <function>dbase_pack</function>.
  </para>
  <para>
   Only dbf file levels 3 (dBASE III+) - 5 (dBASE V) are supported.
   The types of dBase fields available are:
   <table>
    <title>Available types of fields</title>
    <tgroup cols="3">
     <thead>
      <row>
       <entry>Field</entry>
       <entry>dBase Type</entry>
       <entry>Format</entry>
       <entry>Additional information</entry>
      </row>
     </thead>
     <tbody>
      <row>
       <entry><literal>M</literal></entry>
       <entry>Memo</entry>
       <entry>n/a</entry>
       <entry>This type is not supported by PHP, such field will be ignored</entry>
      </row>
      <row>
       <entry><literal>D</literal></entry>
       <entry>Date</entry>
       <entry><literal>YYYYMMDD</literal></entry>
       <entry>The field length is limited to 8</entry>
      </row>
      <row>
       <entry><literal>T</literal></entry>
       <entry>DateTime</entry>
       <entry><literal>YYYYMMDDhhmmss.uuu</literal></entry>
       <entry>(FoxPro) No validity checks are done. Available as of dbase 7.0.0.</entry>
      </row>
      <row>
       <entry><literal>N</literal></entry>
       <entry>Number</entry>
       <entry>A number</entry>
       <entry>
        You must declare a length and a precision (the number of digits
        after the decimal point).
       </entry>
      </row>
      <row>
       <entry><literal>F</literal></entry>
       <entry>Float</entry>
       <entry>A float number</entry>
       <entry>Same as <literal>N</literal>.</entry>
      </row>
      <row>
       <entry><literal>C</literal></entry>
       <entry>String</entry>
       <entry>A string</entry>
       <entry>You must declare a length. When retrieving data, the string
       will be right-padded with spaces to fit the declared length. Overlong
       strings will be silently truncated when storing data.</entry>
      </row>
      <row>
       <entry><literal>L</literal></entry>
       <entry>Boolean</entry>
       <entry>
        <literal>T</literal> or <literal>Y</literal> for &true;, 
        <literal>F</literal> or <literal>N</literal> for &false;,
        <literal>?</literal> for uninitialized.
       </entry>
       <entry>
        As of dbase 7.0.0, returned as a <type>bool</type> (&true; or &false;),
        or &null; for uninitialized fields.
        Formerly, returned as an <type>int</type> (<literal>1</literal> or <literal>0</literal>).
       </entry>
      </row>
     </tbody>
    </tgroup>
   </table>
  </para>
  <note>
   <para>
    As of dbase 7.0.0 nullable fields are supported for
    <constant>DBASE_TYPE_FOXPRO</constant> databases. If a field is nullable,
    passing &null; will set the respective flag, and on later retrieval the field
    value will be &null;.
   </para>
  </note>
  <note>
   <para>
    There is no support for indexes or memo fields.
   </para>
  </note>
 </preface>
 <!-- }}} -->
 
 &reference.dbase.setup;
 &reference.dbase.constants;
 &reference.dbase.reference;

</book>

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