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config.xml: integrated parts removed. restructering, documentation of ini-settings fitting not into an extension safe-mode errorfunc filesystem info misc outcontrol added implicit_flush to ini-settings sesam new structure, ini-settings sybase added magic_quotes_sybase to ini-settings var rsusi: reflect changes git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@97414 c90b9560-bf6c-de11-be94-00142212c4b1
377 lines
12 KiB
XML
377 lines
12 KiB
XML
<?xml version="1.0" encoding="iso-8859-1"?>
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<!-- $Revision: 1.4 $ -->
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<reference id="ref.sesam">
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<title>SESAM database functions</title>
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<titleabbrev>SESAM</titleabbrev>
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<partintro>
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<section id="sesam.intro">
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&reftitle.intro;
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<para>
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SESAM/SQL-Server is a mainframe database system, developed by
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Fujitsu Siemens Computers, Germany. It runs on high-end mainframe
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servers using the operating system BS2000/OSD.
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</para>
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<para>
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In numerous productive BS2000 installations, SESAM/SQL-Server has
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proven
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<itemizedlist>
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<listitem>
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<simpara>
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the ease of use of Java-, Web- and client/server connectivity,
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</simpara>
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</listitem>
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<listitem>
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<simpara>
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the capability to work with an availability of more than
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99.99%,
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</simpara>
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</listitem>
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<listitem>
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<simpara>
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the ability to manage tens and even hundreds of thousands of
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users.
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</simpara>
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</listitem>
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</itemizedlist>
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</para>
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<para>
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There is a <literal>PHP3</literal> SESAM interface available which allows
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database operations via PHP-scripts.
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</para>
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<note>
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<simpara>
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Access to SESAM is only available with the latest CVS-Version of
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<literal>PHP3</literal>. <literal>PHP 4</literal> does not support the
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SESAM database.
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</simpara>
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</note>
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</section>
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&reference.sesam.ini;
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<section id="sesam.cursor-types">
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<title>Cursor Types</title>
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<para>
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The result cursors which are allocated for SQL "select type"
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queries can be either "sequential" or "scrollable". Because of
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the larger memory overhead needed by "scrollable" cursors, the
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default is "sequential".
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</para>
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<para>
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When using "scrollable" cursors, the cursor can be freely
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positioned on the result set. For each "scrollable" query, there
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are global default values for the scrolling type (initialized to:
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<literal>SESAM_SEEK_NEXT</literal>) and the scrolling offset
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which can either be set once by
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<function>sesam_seek_row</function> or each time when fetching a
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row using <function>sesam_fetch_row</function>. When fetching a
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row using a "scrollable" cursor, the following post-processing is
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done for the global default values for the scrolling type and
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scrolling offset:
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<table>
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<title>Scrolled Cursor Post-Processing</title>
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<tgroup cols="2">
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<thead>
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<row>
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<entry>Scroll Type</entry>
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<entry>Action</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry><literal>SESAM_SEEK_NEXT</literal></entry>
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<entry>none</entry>
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</row>
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<row>
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<entry><literal>SESAM_SEEK_PRIOR</literal></entry>
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<entry>none</entry>
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</row>
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<row>
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<entry><literal>SESAM_SEEK_FIRST</literal></entry>
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<entry>
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set scroll type to <literal>SESAM_SEEK_NEXT</literal>
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</entry>
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</row>
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<row>
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<entry><literal>SESAM_SEEK_LAST</literal></entry>
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<entry>
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set scroll type to <literal>SESAM_SEEK_PRIOR</literal>
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</entry>
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</row>
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<row>
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<entry><literal>SESAM_SEEK_ABSOLUTE</literal></entry>
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<entry>Auto-Increment internal offset value</entry>
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</row>
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<row>
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<entry><literal>SESAM_SEEK_RELATIVE</literal></entry>
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<entry>none. (maintain global default
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<parameter>
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offset</parameter> value, which allows for, e.g., fetching
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each 10th row backwards)
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</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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</para>
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</section>
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<section id="sesam.porting-note">
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<title>Porting note</title>
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<para>
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Because in the PHP world it is natural to start indexes at zero
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(rather than 1), some adaptions have been made to the SESAM
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interface: whenever an indexed array is starting with index 1 in
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the native SESAM interface, the PHP interface uses index 0 as a
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starting point. E.g., when retrieving columns with
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<function>sesam_fetch_row</function>, the first column has the
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index 0, and the subsequent columns have indexes up to (but not
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including) the column count ($array["count"]). When porting
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SESAM applications from other high level languages to PHP, be
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aware of this changed interface. Where appropriate, the
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description of the respective php sesam functions include a note
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that the index is zero based.
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</para>
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</section>
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<section id="sesam.security">
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<title>Security concerns</title>
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<para>
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When allowing access to the SESAM databases, the web server user
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should only have as little privileges as possible. For most
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databases, only read access privilege should be granted.
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Depending on your usage scenario, add more access rights as you
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see fit. Never allow full control to any database for any user
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from the 'net! Restrict access to php scripts which must
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administer the database by using password control and/or SSL
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security.
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</para>
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</section>
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<section id="sesam.migration">
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<title>Migration from other SQL databases</title>
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<para>
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No two SQL dialects are ever 100% compatible. When porting
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SQL applications from other database interfaces to SESAM,
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some adaption may be required. The following typical
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differences should be noted:
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<itemizedlist>
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<listitem>
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<simpara>Vendor specific data types</simpara>
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<simpara>
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Some vendor specific data types may have to be replaced by
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standard SQL data types (e.g., <literal>TEXT</literal> could
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be replaced by <literal>VARCHAR(max. size)</literal>).
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</simpara>
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</listitem>
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<listitem>
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<simpara>Keywords as SQL identifiers</simpara>
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<simpara>
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In SESAM (as in standard SQL), such identifiers must be
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enclosed in double quotes (or renamed).
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</simpara>
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</listitem>
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<listitem>
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<simpara>
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Display length in data types
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</simpara>
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<simpara>
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SESAM data types have a precision, not a display
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length. Instead of <literal>int(4)</literal> (intended use:
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integers up to '9999'), SESAM requires simply
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<literal>int</literal> for an implied size of 31 bits. Also,
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the only datetime data types available in SESAM are:
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<literal>DATE</literal>, <literal>TIME(3)</literal> and
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<literal>TIMESTAMP(3)</literal>.
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</simpara>
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</listitem>
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<listitem>
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<simpara>
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SQL types with vendor-specific <literal>unsigned</literal>,
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<literal>zerofill</literal>, or
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<literal>auto_increment</literal> attributes
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</simpara>
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<simpara>
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<literal>Unsigned</literal> and<literal> zerofill</literal>
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are not supported. <literal>Auto_increment</literal> is
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automatic (use <literal>"INSERT ... VALUES(*, ...)"</literal>
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instead of <literal>"... VALUES(0, ...)"</literal> to take
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advantage of SESAM-implied auto-increment.
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</simpara>
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</listitem>
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<listitem>
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<simpara>
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<command>int ... DEFAULT '0000'</command>
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</simpara>
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<simpara>
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Numeric variables must not be initialized with string
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constants. Use <command>DEFAULT 0</command> instead. To
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initialize variables of the datetime SQL data types, the
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initialization string must be prefixed with the respective
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type keyword, as in: <literal> CREATE TABLE exmpl ( xtime
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timestamp(3) DEFAULT TIMESTAMP '1970-01-01 00:00:00.000' NOT
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&null; ); </literal>
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</simpara>
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</listitem>
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<listitem>
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<simpara>
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<command>$count = xxxx_num_rows();</command>
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</simpara>
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<simpara>
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Some databases promise to guess/estimate the number of the
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rows in a query result, even though the returned value is
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grossly incorrect. SESAM does not know the number of rows in
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a query result before actually fetching them. If you REALLY
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need the count, try <command>SELECT COUNT(...) WHERE
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...</command>, it will tell you the number of hits. A second
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query will (hopefully) return the results.
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</simpara>
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</listitem>
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<listitem>
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<simpara>
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<command>DROP TABLE thename;</command>
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</simpara>
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<simpara>
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In SESAM, in the <command>DROP TABLE</command> command, the
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table name must be either followed by the keyword
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<literal>RESTRICT</literal> or
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<literal>CASCADE</literal>. When specifying
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<literal>RESTRICT</literal>, an error is returned if there are
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dependent objects (e.g., VIEWs), while with
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<literal>CASCADE</literal>, dependent objects will be deleted
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along with the specified table.
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</simpara>
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</listitem>
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</itemizedlist>
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</para>
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</section>
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<section id="sesam.sql-types">
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<title>
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Notes on the use of various SQL types
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</title>
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<para>
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SESAM does not currently support the BLOB type. A future version
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of SESAM will have support for BLOB.
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</para>
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<para>
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At the PHP interface, the following type conversions are
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automatically applied when retrieving SQL fields:
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<table>
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<title>SQL to PHP Type Conversions</title>
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<tgroup cols="2">
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<thead>
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<row>
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<entry>SQL Type</entry>
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<entry>PHP Type</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry>SMALLINT, INTEGER</entry>
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<entry><type>integer</type></entry>
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</row>
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<row>
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<entry>NUMERIC, DECIMAL, FLOAT, REAL, DOUBLE</entry>
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<entry><type>float</type></entry>
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</row>
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<row>
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<entry>DATE, TIME, TIMESTAMP</entry>
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<entry><type>string</type></entry>
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</row>
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<row>
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<entry>VARCHAR, CHARACTER</entry>
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<entry><type>string</type></entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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When retrieving a complete row, the result is returned as an
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array. Empty fields are not filled in, so you will have to check
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for the existence of the individual fields yourself (use
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<function>isset</function> or <function>empty</function> to test
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for empty fields). That allows more user control over the
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appearance of empty fields (than in the case of an empty string
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as the representation of an empty field).
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</para>
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</section>
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<section id="sesam.multiple-fields">
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<title>Support of SESAM's "multiple fields" feature</title>
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<para>
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The special "multiple fields" feature of SESAM allows a column to
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consist of an array of fields. Such a "multiple field" column can
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be created like this:
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<example>
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<title>Creating a "multiple field" column</title>
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<programlisting role="sesam">
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<![CDATA[
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CREATE TABLE multi_field_test (
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pkey CHAR(20) PRIMARY KEY,
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multi(3) CHAR(12)
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)
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]]>
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</programlisting>
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</example>
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and can be filled in using:
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<example>
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<title>Filling a "multiple field" column</title>
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<programlisting role="sesam">
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<![CDATA[
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INSERT INTO multi_field_test (pkey, multi(2..3) )
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VALUES ('Second', <'first_val', 'second_val'>)
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]]>
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</programlisting>
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</example>
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Note that (like in this case) leading empty sub-fields are
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ignored, and the filled-in values are collapsed, so that in the
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above example the result will appear as multi(1..2) instead of
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multi(2..3).
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</para>
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<para>
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When retrieving a result row, "multiple columns" are accessed
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like "inlined" additional columns. In the example above, "pkey"
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will have the index 0, and the three "multi(1..3)" columns will
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be accessible as indices 1 through 3.
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</para>
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</section>
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<section id="sesam.seealso">
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&reftitle.seealso;
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<para>
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For specific SESAM details, please refer to <ulink
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url="&url.sesam.en;">the SESAM/SQL-Server documentation
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(english)</ulink> or <ulink url="&url.sesam.de;">the
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SESAM/SQL-Server documentation (german)</ulink>, both available
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online, or use the respective manuals.
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</para>
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</section>
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</partintro>
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&reference.sesam.functions;
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</reference>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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indent-tabs-mode:nil
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sgml-parent-document:nil
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sgml-default-dtd-file:"../../../manual.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:nil
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sgml-local-ecat-files:nil
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End:
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vim600: syn=xml fen fdm=syntax fdl=2 si
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vim: et tw=78 syn=sgml
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vi: ts=1 sw=1
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-->
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