<?xml version="1.0" encoding="utf-8"?>
<page xmlns="http://projectmallard.org/1.0/" type="topic" id="query-execution-perspective" xml:lang="zh-CN">
<info>
  <title type="sort">1</title>
  <link type="guide" xref="index#perspectives"/>
</info>
<title>The query execution perspective</title>
<p>
  Use the query perspective to execute SQL statements. To switch
  to this perspective, use the <guiseq><gui>Perspective</gui><gui>Query execution (SQL)</gui></guiseq>
  menu, or the <keyseq><key>Ctrl</key><key>S</key></keyseq> shortcut.
</p>
<figure>
  <title>Query exec perspective</title>
  <desc>The query exec perspective with one SELECT statement executed</desc>
  <media type="image" mime="image/png" src="figures/query-exec-persp.png"/>
</figure>

<p>
  The perspective is divided in two horizontal panes: the left pane for the user defined favorite statements,
  and the right pane being the action area.
</p>
<p>
  In the figure above, there are two favorites: a SELECT
  statement (named "List customers") and an INSERT statement (named "New customer ...").
  The INSERT statement needs one "name" parameter, whereas the SELECT statement does not require
  any parameter to be executed.
</p>
<p>
  The icon difference between the two illustrates the fact that the INSERT favorite is also
  marked to be an <link xref="actions">action</link>: it will be proposed as an action to
  be executed when the contextual menu is brought up in any grid representation of a resultset.
</p>
<p>
  The left
  part of the perspective lists the favorite statements which have been user defined. Activating a
  favorite (double clicking) resets the SQL text area's contents to the selected statement's SQL.
</p>
<p>
  The right pane is composed of zero or more tabs where the SQL is entered and executed. In each tab
  there is:
</p>
<list>
  <item><p>an SQL area in the top left part</p></item>
  <item><p>command buttons in the top right part</p></item>
  <item><p>execution history in the lower left part</p></item>
  <item><p>execution results in the lower right part</p></item>
</list>

<section id="query-exec-sql">
  <title>SQL 区</title>
  <p>
    The SQL area is an SQL editor. The SQL can be any SQL understood by the database, with the exception
    of <link xref="variables-syntax">variables</link> (which must have a specific syntax).
  </p>
  <p>
    The keyboard shortcuts in the SQL editor are:
  </p>
  <list>
    <item><p><keyseq><key>Ctrl</key><key>SPACE</key></keyseq> to obtain a completion list</p></item>
    <item><p><keyseq><key>Ctrl</key><key>ENTER</key></keyseq> to execute the SQL code</p></item>
    <item><p><keyseq><key>Ctrl</key><key>l</key></keyseq> to clear the editor</p></item>
    <item><p><keyseq><key>Ctrl</key><key>Up</key></keyseq> and
	<keyseq><key>Ctrl</key><key>Down</key></keyseq> to navigate through the editor's history</p></item>
  </list>
</section>

<section id="query-exec-command-buttons">
  <title>Command buttons</title>
  <p>
    The commands available through the command buttons are:
  </p>
  <list>
    <item><p><gui>Clear</gui>: clears the editor (similar to the <keyseq><key>Ctrl</key><key>l</key></keyseq> shortcut)</p></item>
    <item><p><gui>Variables</gui>: shows or hides the <link xref="variables-syntax">variables</link> panel where you can give values to the variables
	present in the SQL code. The panel is automatically shown when a variable is detected in 
	the SQL code</p></item>
    <item><p><gui>Execute</gui>: executes the SQL code. If the SQL code contains some variables which have not been
	set, then a popup first appears requesting the variables to be given values. This is similar
	to the <keyseq><key>Ctrl</key><key>ENTER</key></keyseq> shortcut</p></item>
    <item><p><gui>Indent</gui>: re-indents the SQL code (warning: this removes any comments)</p></item>
    <item><p><gui>Favorites</gui>: adds the current SQL code to the favorites</p></item>
  </list>
</section>

<section id="query-exec-history">
  <title>Execution history</title>
  <p>
    The execution history part contains a list of the past executed statements, ordered by execution date
    along with an indication when the statement was executed (11 minutes in the figure above). Selecting
    an history item displays the corresponding result in the execution results part.
  </p>
  <p>
    The <gui>Copy</gui> button copies the currently selected history item's SQL code to the SQL editor, and the
    <gui>Clear</gui> button removes all the history items.
  </p>
  <p>
    Note that any given history item can also be removed individually using the <key>Suppr</key> key.
  </p>
</section>

<section id="query-exec-results">
  <title>执行结果</title>
  <p>
    The Execution results part displays the execution result of the currently selected execution
    history item, as a table for SELECT statement, giving information for other types of
    statement, or giving the execution error notice if the execution failed.
  </p>
</section>
</page>
