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<appendix id="appendix">
  <title>Database Back-ends</title>

  <sect1 id="foreignlibs">
    <title>How CLSQL finds and loads foreign  libraries</title>
    <para>
      For some database types CLSQL has to load external foreign
      libaries.  These are usually searched for in the standard
      locations the operating system uses but you can tell &clsql; to
      look into other directories as well by using the function
      <function>CLSQL:PUSH-LIBRARY-PATH</function> or by directly
      manipulating the special variable
      <varname>CLSQL:*FOREIGN-LIBRARY-SEARCH-PATHS*</varname>.  If,
      say, the shared library libpq.so needed for PostgreSQL support
      is located in the directory <filename>/opt/foo/</filename> on
      your machine you'd use
      <screen>
	(clsql:push-library-path "/opt/foo/")
      </screen>
  before loading the CLSQL-POSTGRESQL module.  (Note the trailing
  slash above!)

  If you want to combine this with fully automatic loading of
  libraries via ASDF a technique like the following works:

  <screen>
    (defmethod asdf:perform :after ((o asdf:load-op) 
                                    (c (eql (asdf:find-system 'clsql))))
      (funcall (find-symbol (symbol-name '#:push-library-path)
                            (find-package 'clsql))
               #p"/opt/foo/"))
  </screen>
    </para>

    <para>
      Additionally, site-specific initialization can be done using an
initialization file. If the file <filename>/etc/clsql-init.lisp</filename> 
exists, this file will be read after the &clsql; ASDF system is loaded.
This file can contain forms to set site-specific paths as well as change
&clsql; default values.
    </para>
  </sect1>
  <sect1 id="postgresql">
    <title>PostgreSQL</title>
    <sect2>
      <title>Libraries</title>
      <para>The PostgreSQL back-end requires the PostgreSQL C 
      client library (<filename>libpq.so</filename>).  The
      location of this library is specified via 
	  <symbol>*postgresql-so-load-path*</symbol>, which defaults
	  to <filename>/usr/lib/libpq.so</filename>.  Additional flags 
	  to <application>ld</application> needed for linking are
	  specified via <symbol>*postgresql-so-libraries*</symbol>,
	  which defaults to <symbol>("-lcrypt" "-lc")</symbol>.</para>
      </sect2>
      <sect2>
	<title>Initialization</title>
	<para>Use 
	  <screen>
(asdf:operate 'asdf:load-op 'clsql-postgresql)
	</screen>
	  to load the PostgreSQL back-end.  The database type for the
	  PostgreSQL back-end is <symbol>:postgresql</symbol>.</para>
      </sect2>
      <sect2>
	<title>Connection Specification</title>
	<sect3>
	  <title>Syntax of connection-spec</title>
	  <synopsis>
	    (<replaceable>host</replaceable> <replaceable>db</replaceable> <replaceable>user</replaceable> <replaceable>password</replaceable> &amp;optional <replaceable>port</replaceable> <replaceable>options</replaceable> <replaceable>tty</replaceable>)
	  </synopsis>
	</sect3>
	<sect3>
	  <title>Description of connection-spec</title>
	  <para>
	    For every parameter in the connection-spec,
	    <symbol>nil</symbol> indicates that the PostgreSQL default
	    environment variables (see PostgreSQL documentation) will
	    be used, or if those are unset, the compiled-in defaults
	    of the C client library are used.
	  </para>
	  <variablelist>
	    <varlistentry>
	      <term><parameter>host</parameter></term>
	      <listitem>
		<para>String representing the hostname or IP address
		  the PostgreSQL server resides on.  Use the empty
		  string to indicate a connection to localhost via
		  Unix-Domain sockets instead of TCP/IP.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>db</parameter></term>
	      <listitem>
		<para>String representing the name of the database on
		  the server to connect to.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>user</parameter></term>
	      <listitem>
		<para>String representing the user name to use for
		  authentication.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>password</parameter></term>
	      <listitem>
		<para>String representing the unencrypted password to
		  use for authentication.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>port</parameter></term>
	      <listitem>
		<para>String representing the port to use for
		  communication with the PostgreSQL server.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>options</parameter></term>
	      <listitem>
		<para>String representing further runtime options for
		  the PostgreSQL server.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>tty</parameter></term>
	      <listitem>
		<para>String representing the tty or file to use for
		  debugging messages from the PostgreSQL server.</para>
	      </listitem>
	    </varlistentry>
	  </variablelist>
	</sect3>
      </sect2>
      <sect2><title>Notes</title>
      <para>None.</para>
      </sect2>
    </sect1>

    <sect1 id="postgresql-socket">
      <title>PostgreSQL Socket</title>
      <sect2>
	<title>Libraries</title>
	<para>The PostgreSQL Socket back-end needs
	  <emphasis>no</emphasis> access to the PostgreSQL C
	  client library, since it communicates directly with the
	  PostgreSQL server using the published frontend/backend
	  protocol, version 2.0.  This eases installation and makes it
	  possible to dump CMU CL images containing CLSQL and this
	  backend, contrary to backends which require FFI code.</para>
      </sect2>
      <sect2>
	<title>Initialization</title>
	<para>
	  Use 
	  <screen>
(asdf:operate 'asdf:load-op 'clsql-postgresql-socket)
	</screen>
	  to load the PostgreSQL Socket back-end.  The database type
	  for the PostgreSQL Socket back-end is
	  <symbol>:postgresql-socket</symbol>.
	</para>
      </sect2>
      <sect2>
	<title>Connection Specification</title>
	<sect3>
	  <title>Syntax of connection-spec</title>
	  <synopsis>
	    (<replaceable>host</replaceable> <replaceable>db</replaceable> <replaceable>user</replaceable> <replaceable>password</replaceable> &amp;optional <replaceable>port</replaceable> <replaceable>options</replaceable> <replaceable>tty</replaceable>)
	  </synopsis>
	</sect3>
	<sect3>
	  <title>Description of connection-spec</title>
	  <variablelist>
	    <varlistentry>
	      <term><parameter>host</parameter></term>
	      <listitem>
		<para>If this is a string, it represents the hostname or
		  IP address the PostgreSQL server resides on.  In
		  this case communication with the server proceeds via
		  a TCP connection to the given host and port.</para>
		<para>
		  If this is a pathname, then it is assumed to name the
		  directory that contains the server's Unix-Domain
		  sockets.  The full name to the socket is then
		  constructed from this and the port number passed,
		  and communication will proceed via a connection to
		  this unix-domain socket.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>db</parameter></term>
	      <listitem>
		<para>String representing the name of the database on
		  the server to connect to.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>user</parameter></term>
	      <listitem>
		<para>String representing the user name to use for
		  authentication.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>password</parameter></term>
	      <listitem>
		<para>String representing the unencrypted password to
		  use for authentication.  This can be the empty
		  string if no password is required for
		  authentication.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>port</parameter></term>
	      <listitem>
		<para>Integer representing the port to use for
		  communication with the PostgreSQL server.  This
		  defaults to 5432.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>options</parameter></term>
	      <listitem>
		<para>String representing further runtime options for
		  the PostgreSQL server.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>tty</parameter></term>
	      <listitem>
		<para>String representing the tty or file to use for
		  debugging messages from the PostgreSQL server.</para>
	      </listitem>
	    </varlistentry>
	  </variablelist>
	</sect3>
      </sect2>
      <sect2><title>Notes</title>
      <para>None.</para>
      </sect2>
    </sect1>

  <sect1 id="mysql">
    <title>MySQL</title>
    <sect2>
      <title>Libraries</title>
      <para>The &mysql; back-end requires the &mysql; C 
	client library (<filename>libmysqlclient.so</filename>).
	The location of this library is specified 
	via <symbol>*mysql-so-load-path*</symbol>, which defaults
	to <filename>/usr/lib/libmysqlclient.so</filename>.
	Additional flags to <application>ld</application> needed for
	linking are specified via <symbol>*mysql-so-libraries*</symbol>,
	which defaults to <symbol>("-lc")</symbol>.
      </para>
    </sect2>
    <sect2>
      <title>Initialization</title>
      <para>
	Use 
	<screen>
(asdf:operate 'asdf:load-op 'clsql-mysql)
	</screen>
	to load the &mysql; back-end.  The database type for the MySQL
	back-end is <symbol>:mysql</symbol>.
      </para>
      </sect2>
      <sect2>
	<title>Connection Specification</title>
	<sect3>
	  <title>Syntax of connection-spec</title>
	  <synopsis>(<replaceable>host</replaceable> <replaceable>db</replaceable> <replaceable>user</replaceable> <replaceable>password</replaceable> &amp;optional <replaceable>port</replaceable>)</synopsis>
	</sect3>
	<sect3>
	  <title>Description of connection-spec</title>
	  <variablelist>
	    <varlistentry>
	      <term><parameter>host</parameter></term>
	      <listitem>
		<para>String representing the hostname or IP address
		  the &mysql; server resides on, or <symbol>nil</symbol>
		  to indicate the localhost.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>db</parameter></term>
	      <listitem>
		<para>String representing the name of the database on
		  the server to connect to.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>user</parameter></term>
	      <listitem>
		<para>String representing the user name to use for
		  authentication, or <symbol>nil</symbol> to use the
		  current Unix user ID.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>password</parameter></term>
	      <listitem>
		<para>String representing the unencrypted password to
		  use for authentication, or <symbol>nil</symbol> if
		  the authentication record has an empty password
		  field.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>port</parameter></term>
	      <listitem>
		<para>String representing the port to use for
		  communication with the MySQL server.</para>
	      </listitem>
	    </varlistentry>
	  </variablelist>
	</sect3>
      </sect2>
      <sect2><title>Notes</title>
      <sect3><title>FDDL</title> 
      <itemizedlist mark='opencircle'>
        <listitem>
          <para>
            <link
            linkend="drop-index"><function>drop-index</function></link>
            requires a table to be specified with the
            <symbol>:on</symbol> keyword parameter.
          </para>
        </listitem>
        <listitem>
          <para>
            <glossterm linkend="gloss-view">views</glossterm> are not
            supported by &mysql;. 
          </para>
        </listitem>
        <listitem>
          <para>
            The <symbol>:transactions</symbol> keyword argument to
            <link
            linkend="create-table"><function>create-table</function></link>
            controls whether or not the created table is an InnoDB
            table which supports transactions.
          </para>
        </listitem>
        <listitem>
          <para>
            The <symbol>:owner</symbol> keyword argument to the FDDL functions 
            for listing and testing for database objects is ignored. 
          </para>
        </listitem>        
      </itemizedlist>
      </sect3>
      <sect3><title>FDML</title>
      <itemizedlist mark='opencircle'>
        <listitem>
          <para>
            Prior to version 4.1, &mysql; does not support nested
            subqueries in calls to <link
            linkend="select"><function>select</function></link>.
          </para>
        </listitem>
      </itemizedlist>
      </sect3>
      <sect3><title>Symbolic SQL Syntax</title>
      <itemizedlist mark='opencircle'>
        <listitem>
          <para>
            &mysql; does not support the <function>||</function>
            concatenation operator. Use <function>concat</function>
            instead.
          </para>
        </listitem>
        <listitem>
          <para>
            &mysql; does not support the <function>substr</function>
            operator. Use <function>substring</function> instead.
          </para>
        </listitem>
        <listitem>
          <para>
            &mysql; does not support the
            <function>intersect</function> and
            <function>except</function> set operations.
          </para>
        </listitem>
        <listitem>
          <para>
            &mysql; (version 4.0 and later) does not support string
            table aliases unless the server is started with
            ANSI_QUOTES enabled.
          </para>
        </listitem>
      </itemizedlist>
      </sect3>
      </sect2>
    </sect1>
    
    <sect1 id="odbc">
      <title>&odbc;</title>
      <sect2>
	<title>Libraries</title> 
	<para>
	  The &odbc; back-end requires access to an &odbc; driver
	  manager as well as &odbc; drivers for the underlying
	  database server. &clsql; has been tested with
	  <application>unixODBC</application> ODBC Driver Manager as
	  well as Microsoft's ODBC manager.  These driver managers
	  have been tested with the <ulink
	  url="http://odbc.postgresql.org">
	  <citetitle>psqlODBC</citetitle></ulink> driver for
	  &postgresql; and the <ulink
	  url="http://www.mysql.com/products/connector/odbc/">
	  <citetitle>MyODBC</citetitle></ulink> driver for &mysql;.
	</para>
      </sect2>
      <sect2>
	<title>Initialization</title>
	<para>
	  Use 
	  <screen>
(asdf:operate 'asdf:load-op 'clsql-odbc)
	  </screen>
	  to load the &odbc; back-end.  The database type for the &odbc;
	  back-end is <symbol>:odbc</symbol>.
	</para>
      </sect2>
      <sect2>
	<title>Connection Specification</title>
	<sect3>
	  <title>Syntax of connection-spec</title>
	  <synopsis>(<replaceable>dsn</replaceable> <replaceable>user</replaceable> <replaceable>password</replaceable> &amp;key <replaceable>connection-string</replaceable>)</synopsis>
	</sect3>
	<sect3>
	  <title>Description of connection-spec</title>
	  <variablelist>
	    <varlistentry>
	      <term><parameter>dsn</parameter></term>
	      <listitem>
		<para>String representing the ODBC data source name.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>user</parameter></term>
	      <listitem>
		<para>String representing the user name to use for
		  authentication.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>password</parameter></term>
	      <listitem>
		<para>String representing the unencrypted password to
		  use for authentication.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>connection-string</parameter></term>
	      <listitem>
		<para>Raw connection string passed to the underlying
		ODBC driver. Allows bypassing creating a DSN on the
		server.</para>
	      </listitem>
	    </varlistentry>

	  </variablelist>
	</sect3>
      </sect2>
      <sect2><title>Notes</title>
      <sect3><title>FDDL</title> 
      <itemizedlist mark='opencircle'>
        <listitem>
          <para>
            The <symbol>:owner</symbol> keyword argument to the FDDL functions 
            for listing and testing for database objects is ignored. 
          </para>
        </listitem>        
      </itemizedlist>
      </sect3>
      </sect2>
      <sect2><title>Connect Examples</title>
	<screen>

;; assumes a "mssql" DSN is configured on the lisp host, specifying database server
;;  and database name.
> (clsql:connect '("mssql" "database-user" "database-password") 
               :database-type :odbc)
=> #&lt;CLSQL-ODBC:ODBC-DATABASE mssql/database-user OPEN {100756D123}&gt;

;; no DSN on the lisp host, specify connection information via :connection-string
> (clsql:connect '("friendly-server-name" "friendly-username" "" 
		 :connection-string "DRIVER={FreeTDS};SERVER=mssql-server;DATABASE=database-name;UID=database-user;PWD=database-password;PORT=1433;TDS_Version=8.0;APP=clsql") 
               :database-type :odbc)
=> #&lt;CLSQL-ODBC:ODBC-DATABASE friendly-server-name/friendly-username OPEN {100756D123}&gt;</screen>	
	<para>
          The <symbol>friendly-server-name</symbol>
          and <symbol>friendly-username</symbol> are only used when
          printing the connection object to a stream.
        </para>
      </sect2>
    </sect1>

    <sect1 id="aodbc">
      <title>&aodbc;</title>
      <sect2>
	<title>Libraries</title> <para>The &aodbc; back-end requires
	access to the &odbc; interface of &acl; named DBI. This
	interface is not available in the trial version of
	&acl;</para>
      </sect2>
      <sect2>
	<title>Initialization</title>
	<para>
	  Use 
	  <screen>
(require 'aodbc-v2)
(asdf:operate 'asdf:load-op 'clsql-aodbc)
	  </screen>
	  to load the &aodbc; back-end.  The database type for the &aodbc;
	  back-end is <symbol>:aodbc</symbol>.
	</para>
      </sect2>
      <sect2>
	<title>Connection Specification</title>
	<sect3>
	  <title>Syntax of connection-spec</title>
	  <synopsis>
	    (<replaceable>dsn</replaceable> <replaceable>user</replaceable> <replaceable>password</replaceable>)
	  </synopsis>
	</sect3>
	<sect3>
	  <title>Description of connection-spec</title>
	  <variablelist>
	    <varlistentry>
	      <term><parameter>dsn</parameter></term>
	      <listitem>
		<para>String representing the ODBC data source name.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>user</parameter></term>
	      <listitem>
		<para>String representing the user name to use for
		  authentication.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>password</parameter></term>
	      <listitem>
		<para>String representing the unencrypted password to
		  use for authentication.</para>
	      </listitem>
	    </varlistentry>
	  </variablelist>
	</sect3>
      </sect2>
      <sect2><title>Notes</title>
      <para>
        None. 
      </para>
      </sect2>
    </sect1>

    <sect1 id="sqlite">
      <title>&sqlite;</title>
      <sect2>
	<title>Libraries</title> <para>The &sqlite; back-end requires
	the &sqlite; shared library file. Its default file name is
	<filename>/usr/lib/libsqlite.so</filename>.</para>
      </sect2>
      <sect2>
	<title>Initialization</title>
	<para>
	  Use 
	  <screen>
(asdf:operate 'asdf:load-op 'clsql-sqlite)
	  </screen>
	  to load the &sqlite; back-end.  The database type for the &sqlite;
	  back-end is <symbol>:sqlite</symbol>.
	</para>
      </sect2>
      <sect2>
	<title>Connection Specification</title>
	<sect3>
	  <title>Syntax of connection-spec</title>
	  <synopsis>(<replaceable>filename</replaceable>)</synopsis>
	</sect3>
	<sect3>
	  <title>Description of connection-spec</title>
	  <variablelist>
	    <varlistentry>
	      <term><parameter>filename</parameter></term>
	      <listitem>
		<para>String or pathname representing the filename of
		the &sqlite; database file.</para>
	      </listitem>
	    </varlistentry>
	  </variablelist>
	</sect3>
      </sect2>
      <sect2><title>Notes</title>
      <sect3><title>Connection</title> 
      <itemizedlist mark='opencircle'>
        <listitem>
          <para>
            Passing <parameter>filename</parameter> a value of
            <filename>:memory:</filename> will create a database in
            physical memory instead of using a file on disk.
          </para>
        </listitem>        
        <listitem>
          <para>
            Some operations will be many times faster if database
            integrity checking is disabled by setting the SYNCHRONOUS
            flag to OFF (see the SQLITE manual for details).
          </para>
        </listitem>
      </itemizedlist>
      </sect3>
      <sect3><title>FDDL</title> 
      <itemizedlist mark='opencircle'>
        <listitem>
          <para>
            The <symbol>:owner</symbol> keyword argument to the FDDL functions 
            for listing and testing for database objects is ignored. 
          </para>
        </listitem>        
        <listitem>
          <para>
            The <symbol>:column-list</symbol> keyword argument to
            <link
            linkend="create-view"><function>create-view</function></link>
            is not supported by &sqlite;. 
          </para>
        </listitem>
      </itemizedlist>
      </sect3>
      <sect3><title>Symbolic SQL Syntax</title>
      <itemizedlist mark='opencircle'>
        <listitem>
          <para>
            &sqlite; does not support the <function>all</function>,
            <function>some</function>, <function>any</function> and
            <function>exists</function> subquery operations. 
          </para>
        </listitem>
      </itemizedlist>
      </sect3>
      </sect2>
    </sect1>

    <sect1 id="sqlite3">
      <title>&sqlite3;</title>
      <sect2>
	<title>Libraries</title> <para>The &sqlite3; back-end requires
	the &sqlite3; shared library file. Its default file name is
	<filename>/usr/lib/libsqlite3.so</filename>.</para>
      </sect2>
      <sect2>
	<title>Initialization</title>
	<para>
	  Use 
	  <screen>
(asdf:operate 'asdf:load-op 'clsql-sqlite3)
	  </screen>
	  to load the &sqlite3; back-end.  The database type for the &sqlite3;
	  back-end is <symbol>:sqlite3</symbol>.
	</para>
      </sect2>
      <sect2>
	<title>Connection Specification</title>
	<sect3>
	  <title>Syntax of connection-spec</title>
	  <synopsis>(<replaceable>filename</replaceable> &amp;optional <replaceable>init-function</replaceable>)</synopsis>
	</sect3>
	<sect3>
	  <title>Description of connection-spec</title>
	  <variablelist>
	    <varlistentry>
	      <term><parameter>filename</parameter></term>
	      <listitem>
		<para>String representing the filename of the &sqlite3;
		database file.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>init-function</parameter></term>
	      <listitem>
		<para>
		 A function designator.
		 <replaceable>init-function</replaceable> takes a
		 single argument of type
		 <type>sqlite3:sqlite3-db</type>, a foreign pointer to
		 the C descriptor of the newly opened database.
		 <replaceable>init-function</replaceable> is called by
		 the back-end immediately after &sqlite3;
		 <function>sqlite3_open</function> library function,
		 and can be used to perform optional database
		 initializations by calling foreign functions in the
		 &sqlite3; library.
		</para>
		<para>
		 An example of an initialization function which
		 defines a new collating sequence for text columns is
		 provided in
		 <filename>./examples/sqlite3/init-func/</filename>.
		</para>
	      </listitem>
	    </varlistentry>
	  </variablelist>
	</sect3>
      </sect2>
      <sect2><title>Notes</title>
      <sect3><title>Connection</title> 
      <itemizedlist mark='opencircle'>
        <listitem>
          <para>
            Passing <parameter>filename</parameter> a value of
            <filename>:memory:</filename> will create a database in
            physical memory instead of using a file on disk.
          </para>
        </listitem>        
        <listitem>
          <para>
            Some operations will be many times faster if database
            integrity checking is disabled by setting the SYNCHRONOUS
            flag to OFF (see the SQLITE manual for details).
          </para>
        </listitem>
      </itemizedlist>
      </sect3>
      <sect3><title>FDDL</title> 
      <itemizedlist mark='opencircle'>
        <listitem>
          <para>
            The <symbol>:owner</symbol> keyword argument to the FDDL functions 
            for listing and testing for database objects is ignored. 
          </para>
        </listitem>        
        <listitem>
          <para>
            The <symbol>:column-list</symbol> keyword argument to
            <link
            linkend="create-view"><function>create-view</function></link>
            is not supported by &sqlite3;. 
          </para>
        </listitem>
      </itemizedlist>
      </sect3>
      <sect3><title>Symbolic SQL Syntax</title>
      <itemizedlist mark='opencircle'>
        <listitem>
          <para>
            &sqlite3; does not support the <function>all</function>,
            <function>some</function>, <function>any</function> and
            <function>exists</function> subquery operations. 
          </para>
        </listitem>
      </itemizedlist>
      </sect3>
      </sect2>
    </sect1>

  <sect1 id="oracle">
    <title>Oracle</title>
    <sect2>
      <title>Libraries</title>
      <para>The &oracle; back-end requires the &oracle; OCI client
      library. (<filename>libclntsh.so</filename>).  The location of
      this library is specified relative to the
      <symbol>ORACLE_HOME</symbol> value in the operating system
      environment.
      </para>
    </sect2>
    <sect2>
      <title>Library Versions</title>
      <para>
	&clsql; has tested sucessfully using the client library from
	Oracle 9i and Oracle 10g server installations as well as
	Oracle's 10g Instant Client library. For Oracle 8 and earlier
	versions, there is vestigial support by pushing the symbol
	<symbol>:oci7</symbol> onto <symbol>cl:*features*</symbol>
	prior to loading the <filename>clsql-oracle</filename> &asdf;
	system.
	<screen>
	  (push :oci7 cl:*features*)
	  (asdf:operate 'asdf:load-op 'clsql-oracle)
	</screen>
      </para>
    </sect2>
    <sect2>
      <title>Initialization</title>
      <para>
	Use 
	<screen>
(asdf:operate 'asdf:load-op 'clsql-oracle)
	</screen>
	to load the &oracle; back-end.  The database type for the Oracle
	back-end is <symbol>:oracle</symbol>.
      </para>
      </sect2>
      <sect2>
	<title>Connection Specification</title>
	<sect3>
	  <title>Syntax of connection-spec</title>
	  <synopsis>(<replaceable>global-name</replaceable> <replaceable>user</replaceable> <replaceable>password</replaceable>)</synopsis>
	</sect3>
	<sect3>
	  <title>Description of connection-spec</title>
	  <variablelist>
	    <varlistentry>
	      <term><parameter>global-name</parameter></term>
	      <listitem>
		<para>String representing the global name of the Oracle database.
		  This is looked up through the tnsnames.ora file.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>user</parameter></term>
	      <listitem>
		<para>String representing the user name to use for
		  authentication.</para>
	      </listitem>
	    </varlistentry>
	    <varlistentry>
	      <term><parameter>password</parameter></term>
	      <listitem>
		<para>String representing the password to
		  use for authentication..</para>
	      </listitem>
	    </varlistentry>
	  </variablelist>
	</sect3>
      </sect2>
      <sect2><title>Notes</title>
      <sect3><title>Symbolic SQL Syntax</title>
      <itemizedlist mark='opencircle'>
        <listitem>
          <para>
            The <function>userenv</function> operator is &oracle; specific. 
          </para>
        </listitem>
        <listitem>
          <para>
            &oracle; does not support the <function>except</function>
            operator. Use <function>minus</function> instead.
          </para>
        </listitem>
        <listitem>
          <para>
            &oracle; does not support the <function>all</function>,
            <function>some</function>, <function>any</function>
            subquery operations.
          </para>
        </listitem>
      </itemizedlist>
      </sect3>
      <sect3><title>Transactions</title>
      <itemizedlist mark='opencircle'>
        <listitem>
          <para>
            By default, &clsql; starts in transaction AUTOCOMMIT mode
            (see <link
            linkend="set-autocommit"><function>set-autocommit</function></link>).
            To begin a transaction in autocommit mode, <link
            linkend="start-transaction"><function>start-transaction</function></link>
            has to be called explicitly.
          </para>
        </listitem>
      </itemizedlist>
      </sect3>
      </sect2> 
    </sect1>

  </appendix>