psql-ref.sgml

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

        omitted the current user name is assumed. </para>

        <para>
        As a special rule, <command>\connect</command> without any
        arguments will connect to the default database as the default
        user (as you would have gotten by starting
        <application>psql</application> without any arguments).
        </para>

        <para>
        If the connection attempt failed (wrong user name, access
        denied, etc.), the previous connection will be kept if and only
        if <application>psql</application> is in interactive mode. When
        executing a non-interactive script, processing will immediately
        stop with an error. This distinction was chosen as a user
        convenience against typos on the one hand, and a safety
        mechanism that scripts are not accidentally acting on the wrong
        database on the other hand.
        </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><literal>\copy <replaceable class="parameter">table</replaceable>
        [ ( <replaceable class="parameter">column_list</replaceable> ) ]
        { <literal>from</literal> | <literal>to</literal> }
        { <replaceable class="parameter">filename</replaceable> | stdin | stdout | pstdin | pstdout }
        [ with ]
            [ oids ]
            [ delimiter [ as ] '<replaceable class="parameter">character</replaceable>' ]
            [ null [ as ] '<replaceable class="parameter">string</replaceable>' ]
            [ csv [ quote [ as ] '<replaceable class="parameter">character</replaceable>' ]
            [ escape [ as ] '<replaceable class="parameter">character</replaceable>' ]
            [ force quote <replaceable class="parameter">column_list</replaceable> ]
            [ force not null <replaceable class="parameter">column_list</replaceable> ] ]</literal>
        </term>

        <listitem>
        <para>
        Performs a frontend (client) copy. This is an operation that
        runs an <acronym>SQL</acronym> <xref linkend="SQL-COPY"
        endterm="SQL-COPY-title"> command, but instead of the server
        reading or writing the specified file,
        <application>psql</application> reads or writes the file and
        routes the data between the server and the local file system.
        This means that file accessibility and privileges are those of
        the local user, not the server, and no SQL superuser
        privileges are required.
        </para>

        <para>
        The syntax of the command is similar to that of the
        <acronym>SQL</acronym> <xref linkend="sql-copy"
        endterm="sql-copy-title"> command.  Note that, because of this,
        special parsing rules apply to the <command>\copy</command>
        command. In particular, the variable substitution rules and
        backslash escapes do not apply.
        </para>

        <para>
        <literal>\copy <replaceable
        class="parameter">table</replaceable> from <replaceable
        class="parameter">stdin | stdout</replaceable></literal>
        reads/writes based on the command input and output respectively.
        All rows are read from the same source that issued the command,
        continuing until <literal>\.</literal> is read or the stream
        reaches <acronym>EOF</>. Output is sent to the same place as
        command output. To read/write from
        <application>psql</application>'s standard input or output, use
        <literal>pstdin</> or <literal>pstdout</>. This option is useful
        for populating tables in-line within a SQL script file.
        </para>

        <tip>
        <para>
        This operation is not as efficient as the <acronym>SQL</acronym>
        <command>COPY</command> command because all data must pass
        through the client/server connection. For large
        amounts of data the <acronym>SQL</acronym> command may be preferable.
        </para>
        </tip>

        </listitem>
      </varlistentry>

      <varlistentry>
        <term><literal>\copyright</literal></term>
        <listitem>
        <para>
        Shows the copyright and distribution terms of
        <productname>PostgreSQL</productname>.
        </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><literal>\d [ <replaceable class="parameter">pattern</replaceable> ]</literal></term>
        <term><literal>\d+ [ <replaceable class="parameter">pattern</replaceable> ]</literal></term>

        <listitem>
        <para>
        For each relation (table, view, index, or sequence) matching the
        <replaceable class="parameter">pattern</replaceable>, show all
        columns, their types, the tablespace (if not the default) and any special
        attributes such as <literal>NOT NULL</literal> or defaults, if
        any. Associated indexes, constraints, rules, and triggers are
        also shown, as is the view definition if the relation is a view.
        (<quote>Matching the pattern</> is defined below.)
        </para>

        <para>
        The command form <literal>\d+</literal> is identical, except that
        more information is displayed: any comments associated with the
        columns of the table are shown, as is the presence of OIDs in the
        table.
        </para>

        <note>
        <para>
        If <command>\d</command> is used without a
        <replaceable class="parameter">pattern</replaceable> argument, it is
        equivalent to <command>\dtvs</command> which will show a list of
        all tables, views, and sequences. This is purely a convenience
        measure.
        </para>
        </note>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><literal>\da [ <replaceable class="parameter">pattern</replaceable> ]</literal></term>

        <listitem>
        <para>
        Lists all available aggregate functions, together with the data
        type they operate on. If <replaceable
        class="parameter">pattern</replaceable>
        is specified, only aggregates whose names match the pattern are shown.
        </para>
        </listitem>
      </varlistentry>


      <varlistentry>
        <term><literal>\db [ <replaceable class="parameter">pattern</replaceable> ]</literal></term>
        <term><literal>\db+ [ <replaceable class="parameter">pattern</replaceable> ]</literal></term>

        <listitem>
        <para>
        Lists all available tablespaces. If <replaceable
        class="parameter">pattern</replaceable>
        is specified, only tablespaces whose names match the pattern are shown.
        If <literal>+</literal> is appended to the command name, each object 
        is listed with its associated permissions.
        </para>
        </listitem>
      </varlistentry>


      <varlistentry>
        <term><literal>\dc [ <replaceable class="parameter">pattern</replaceable> ]</literal></term>
        <listitem>
        <para>
        Lists all available conversions between character-set encodings.
        If <replaceable class="parameter">pattern</replaceable>
        is specified, only conversions whose names match the pattern are
        listed.
        </para>
        </listitem>
      </varlistentry>


      <varlistentry>
        <term><literal>\dC</literal></term>
        <listitem>
        <para>
        Lists all available type casts.
        </para>
        </listitem>
      </varlistentry>


      <varlistentry>
        <term><literal>\dd [ <replaceable class="parameter">pattern</replaceable> ]</literal></term>
        <listitem>
        <para>
        Shows the descriptions of objects matching the <replaceable
        class="parameter">pattern</replaceable>, or of all visible objects if
        no argument is given.  But in either case, only objects that have
        a description are listed.
        (<quote>Object</quote> covers aggregates, functions, operators,
        types, relations (tables, views, indexes, sequences, large
        objects), rules, and triggers.) For example:
<programlisting>
=&gt; <userinput>\dd version</userinput>
                     Object descriptions
   Schema   |  Name   |  Object  |        Description
------------+---------+----------+---------------------------
 pg_catalog | version | function | PostgreSQL version string
(1 row)
</programlisting>
        </para>

        <para>
        Descriptions for objects can be created with the <xref
        linkend="sql-comment" endterm="sql-comment-title">
        <acronym>SQL</acronym> command.
       </para>
        </listitem>
      </varlistentry>


      <varlistentry>
        <term><literal>\dD [ <replaceable class="parameter">pattern</replaceable> ]</literal></term>
        <listitem>
        <para>
        Lists all available domains. If <replaceable
        class="parameter">pattern</replaceable>
        is specified, only matching domains are shown.
        </para>
        </listitem>
      </varlistentry>


      <varlistentry>
        <term><literal>\df [ <replaceable class="parameter">pattern</replaceable> ]</literal></term>
        <term><literal>\df+ [ <replaceable class="parameter">pattern</replaceable> ]</literal></term>

        <listitem>
        <para>
        Lists available functions, together with their argument and
        return types. If <replaceable
        class="parameter">pattern</replaceable>
        is specified, only functions whose names match the pattern are shown.
        If the form <literal>\df+</literal> is used, additional information about
        each function, including language and description, is shown.
        </para>

        <note>
        <para>
        To look up functions taking argument or returning values of a specific
        type, use your pager's search capability to scroll through the <literal>\df</>
        output.
        </para>

        <para>
        To reduce clutter, <literal>\df</> does not show data type I/O
        functions.  This is implemented by ignoring functions that accept
        or return type <type>cstring</>.
        </para>
        </note>

        </listitem>
      </varlistentry>


      <varlistentry>
        <term><literal>\dg [ <replaceable class="parameter">pattern</replaceable> ]</literal></term>
        <listitem>
        <para>
        Lists all database roles. If <replaceable
        class="parameter">pattern</replaceable> is specified, only
        those roles whose names match the pattern are listed.
        (This command is now effectively the same as <literal>\du</>.)
        </para>
        </listitem>
      </varlistentry>


      <varlistentry>
        <term><literal>\distvS [ <replaceable class="parameter">pattern</replaceable> ]</literal></term>

        <listitem>
        <para>
        This is not the actual command name: the letters
        <literal>i</literal>, <literal>s</literal>, <literal>t</literal>,
        <literal>v</literal>, <literal>S</literal> stand for index,
        sequence, table, view, and system table, respectively. You can
        specify any or all of these letters, in any order, to obtain a
        listing of all the matching objects.  The letter S restricts the
        listing to system objects; without <literal>S</literal>, only
        non-system objects are shown.  If <literal>+</literal> is appended
        to the command name, each object is listed with its associated
        description, if any.
        </para>

        <para>
        If <replaceable class="parameter">pattern</replaceable> is
        specified, only objects whose names match the pattern are listed.
        </para>
        </listitem>
      </varlistentry>


      <varlistentry>
        <term><literal>\dl</literal></term>
        <listitem>
        <para>
        This is an alias for <command>\lo_list</command>, which shows a
        list of large objects.
        </para>
        </listitem>
      </varlistentry>


      <varlistentry>
        <term><literal>\dn [ <replaceable class="parameter">pattern</replaceable> ]</literal></term>
        <term><literal>\dn+ [ <replaceable class="parameter">pattern</replaceable> ]</literal></term>

        <listitem>
        <para>
        Lists all available schemas (namespaces). If <replaceable
        class="parameter">pattern</replaceable> (a regular expression)
        is specified, only schemas whose names match the pattern are listed.
        Non-local temporary schemas are suppressed.  If <literal>+</literal>
        is appended to the command name, each object is listed with its associated
        permissions and description, if any.
        </para>
        </listitem>
      </varlistentry>


      <varlistentry>
        <term><literal>\do [ <replaceable class="parameter">pattern</replaceable> ]</literal></term>
        <listitem>
        <para>
        Lists available operators with their operand and return types.
        If <replaceable class="parameter">pattern</replaceable> is
        specified, only operators whose names match the pattern are listed.
        </para>
        </listitem>
      </varlistentry>


      <varlistentry>
        <term><literal>\dp [ <replaceable class="parameter">pattern</replaceable> ]</literal></term>
        <listitem>
        <para>
        Produces a list of all available tables, views and sequences with their
        associated access privileges.
        If <replaceable class="parameter">pattern</replaceable> is
        specified, only tables, views and sequences whose names match the pattern are listed.
        </para>

        <para>
        The commands <command>GRANT</command> and
        <command>REVOKE</command> are used to set access privileges.
        See <xref linkend="sql-grant" endterm="sql-grant-title">
        for more information.
        </para>
        </listitem>
      </varlistentry>