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Lu, Huayi a24ca60074 DWS DEVELOPER 811 version 
Reviewed-by: Hasko, Vladimir <vladimir.hasko@t-systems.com>
Co-authored-by: Lu, Huayi <luhuayi@huawei.com>
Co-committed-by: Lu, Huayi <luhuayi@huawei.com>
2023-01-19 13:37:49 +00:00

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<a name="EN-US_TOPIC_0000001145510991"></a><a name="EN-US_TOPIC_0000001145510991"></a>
<h1 class="topictitle1">ALTER SESSION</h1>
<div id="body8662426"><div class="section" id="EN-US_TOPIC_0000001145510991__s16bb1a2b120748559a4fd2cfe746c9f2"><h4 class="sectiontitle">Function</h4><p id="EN-US_TOPIC_0000001145510991__a6145022253704fc3a1a3e997a0a278ee"><strong id="EN-US_TOPIC_0000001145510991__en-us_topic_0058965705_b3749138185119">ALTER SESSION</strong> defines or modifies the conditions or parameters that affect the current session. Modified session parameters are kept until the current session is disconnected.</p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145510991__sa9e57724d49846aabc39ec8fb33baf00"><h4 class="sectiontitle">Precautions</h4><ul id="EN-US_TOPIC_0000001145510991__ubfbd159c84e645bb8dfae1c544f68ca8"><li id="EN-US_TOPIC_0000001145510991__l60a5cbd492204b129033d7d44bffd078">If the <strong id="EN-US_TOPIC_0000001145510991__b71287757535733">START TRANSACTION</strong> command is not executed before the <strong id="EN-US_TOPIC_0000001145510991__b34199387235733">SET TRANSACTION</strong> command, the transaction is ended instantly and the command does not take effect.</li><li id="EN-US_TOPIC_0000001145510991__le2176e8a5b5d4dc28a5cbf7ef8db37cc">You can use the transaction_mode(s) method declared in the <strong id="EN-US_TOPIC_0000001145510991__b4370402635733">START TRANSACTION</strong> command to avoid using the <strong id="EN-US_TOPIC_0000001145510991__b19117868335733">SET TRANSACTION</strong> command.</li></ul>
</div>
<div class="section" id="EN-US_TOPIC_0000001145510991__s54a8c87c07c143fc82d827afa3845b22"><h4 class="sectiontitle">Syntax</h4><ul id="EN-US_TOPIC_0000001145510991__ubb3e96b2a1bb49aeb2a1bb1869662602"><li id="EN-US_TOPIC_0000001145510991__l44fe53fc0dcc42a2b7b7ccd9e09a095b">Set transaction parameters of a session.<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001145510991__sa18a57883e4b4f628aa7d0756ae880e8"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">ALTER</span><span class="w"> </span><span class="k">SESSION</span><span class="w"> </span><span class="k">SET</span><span class="w"> </span><span class="p">[</span><span class="w"> </span><span class="k">SESSION</span><span class="w"> </span><span class="k">CHARACTERISTICS</span><span class="w"> </span><span class="k">AS</span><span class="w"> </span><span class="p">]</span><span class="w"> </span><span class="k">TRANSACTION</span><span class="w"></span>
<span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="k">ISOLATION</span><span class="w"> </span><span class="k">LEVEL</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="k">READ</span><span class="w"> </span><span class="k">COMMITTED</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">READ</span><span class="w"> </span><span class="k">UNCOMMITTED</span><span class="w"> </span><span class="err">}</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="k">READ</span><span class="w"> </span><span class="k">ONLY</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">READ</span><span class="w"> </span><span class="k">WRITE</span><span class="w"> </span><span class="err">}</span><span class="w"> </span><span class="err">}</span><span class="w"> </span><span class="p">[,</span><span class="w"> </span><span class="p">...]</span><span class="w"> </span><span class="p">;</span><span class="w"></span>
</pre></div></td></tr></table></div>
</div>
</li><li id="EN-US_TOPIC_0000001145510991__l0599e1b59d8a407487f1be9678b7715c">Set other running parameters of a session.<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001145510991__s1fcd1764d0fa410e880854be030d11d6"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal"> 1</span>
<span class="normal"> 2</span>
<span class="normal"> 3</span>
<span class="normal"> 4</span>
<span class="normal"> 5</span>
<span class="normal"> 6</span>
<span class="normal"> 7</span>
<span class="normal"> 8</span>
<span class="normal"> 9</span>
<span class="normal">10</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">ALTER</span><span class="w"> </span><span class="k">SESSION</span><span class="w"> </span><span class="k">SET</span><span class="w"> </span>
<span class="w"> </span><span class="err">{{</span><span class="n">config_parameter</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="k">TO</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="err">}</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="n">value</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">DEFAULT</span><span class="w"> </span><span class="err">}</span><span class="w"></span>
<span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">FROM</span><span class="w"> </span><span class="k">CURRENT</span><span class="w"> </span><span class="err">}}</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">CURRENT_SCHEMA</span><span class="w"> </span><span class="p">[</span><span class="w"> </span><span class="k">TO</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">]</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="k">schema</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">DEFAULT</span><span class="w"> </span><span class="err">}</span><span class="w"></span>
<span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">TIME</span><span class="w"> </span><span class="k">ZONE</span><span class="w"> </span><span class="n">time_zone</span><span class="w"></span>
<span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">SCHEMA</span><span class="w"> </span><span class="k">schema</span><span class="w"></span>
<span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">NAMES</span><span class="w"> </span><span class="n">encoding_name</span><span class="w"></span>
<span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">ROLE</span><span class="w"> </span><span class="n">role_name</span><span class="w"> </span><span class="n">PASSWORD</span><span class="w"> </span><span class="s1">'password'</span><span class="w"></span>
<span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">SESSION</span><span class="w"> </span><span class="k">AUTHORIZATION</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="n">role_name</span><span class="w"> </span><span class="n">PASSWORD</span><span class="w"> </span><span class="s1">'password'</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">DEFAULT</span><span class="w"> </span><span class="err">}</span><span class="w"></span>
<span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">XML</span><span class="w"> </span><span class="k">OPTION</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="n">DOCUMENT</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">CONTENT</span><span class="w"> </span><span class="err">}</span><span class="w"></span>
<span class="w"> </span><span class="err">}</span><span class="w"> </span><span class="p">;</span><span class="w"></span>
</pre></div></td></tr></table></div>
</div>
</li></ul>
</div>
<div class="section" id="EN-US_TOPIC_0000001145510991__s5942eadc3335476eb6a6891ac2b04c05"><h4 class="sectiontitle">Parameter Description</h4><p id="EN-US_TOPIC_0000001145510991__a8fadd4a33b194b6e9f7b421e7b39b824">To modify the description of parameters related to the session, see <a href="dws_06_0220.html#EN-US_TOPIC_0000001145510673__se8530cae21fd4932a87b96aedaebc0a9">Parameter Description</a> of the <strong id="EN-US_TOPIC_0000001145510991__b143921837151615">SET</strong> syntax.</p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145510991__sa9f477c6b0de4cba9ff01c597dbcb9dd"><h4 class="sectiontitle">Examples</h4><p id="EN-US_TOPIC_0000001145510991__p1145131162112">Create the <strong id="EN-US_TOPIC_0000001145510991__b151031508165">ds</strong> schema.</p>
<pre class="screen" id="EN-US_TOPIC_0000001145510991__screen845412256325">CREATE SCHEMA ds;</pre>
<p id="EN-US_TOPIC_0000001145510991__p34501611102116">Set the search path of the schema.</p>
<pre class="screen" id="EN-US_TOPIC_0000001145510991__screen15643143253216">SET SEARCH_PATH TO ds, public;</pre>
<p id="EN-US_TOPIC_0000001145510991__p945061120214">Set the time/date type to the traditional postgres format (date before month).</p>
<pre class="screen" id="EN-US_TOPIC_0000001145510991__screen45041140183215">SET DATESTYLE TO postgres, dmy;</pre>
<p id="EN-US_TOPIC_0000001145510991__p7450171192111">Set the character code of the current session to UTF8.</p>
<pre class="screen" id="EN-US_TOPIC_0000001145510991__screen131981547163219">ALTER SESSION SET NAMES 'UTF8';</pre>
<p id="EN-US_TOPIC_0000001145510991__p15449611162117">Set the time zone to Berkeley of California.</p>
<pre class="screen" id="EN-US_TOPIC_0000001145510991__screen1554819541326">SET TIME ZONE 'PST8PDT';</pre>
<p id="EN-US_TOPIC_0000001145510991__p344911114218">Set the time zone to Italy.</p>
<pre class="screen" id="EN-US_TOPIC_0000001145510991__screen1743811213313">SET TIME ZONE 'Europe/Rome';</pre>
<p id="EN-US_TOPIC_0000001145510991__p16449151119211">Set the current schema.</p>
<pre class="screen" id="EN-US_TOPIC_0000001145510991__screen7960108193212">ALTER SESSION SET CURRENT_SCHEMA TO tpcds;</pre>
<p id="EN-US_TOPIC_0000001145510991__p19448311182113">Set <strong id="EN-US_TOPIC_0000001145510991__b9395111153313">XML OPTION</strong> to <strong id="EN-US_TOPIC_0000001145510991__b93951919336">DOCUMENT</strong>.</p>
<pre class="screen" id="EN-US_TOPIC_0000001145510991__screen1717461163211">ALTER SESSION SET XML OPTION DOCUMENT;</pre>
<p id="EN-US_TOPIC_0000001145510991__p1744831102114">Create the role <strong id="EN-US_TOPIC_0000001145510991__b105981655334">joe</strong>, and set the session role to <strong id="EN-US_TOPIC_0000001145510991__b859913518335">joe</strong>.</p>
<pre class="screen" id="EN-US_TOPIC_0000001145510991__screen105046549317">CREATE ROLE joe WITH PASSWORD '<em id="EN-US_TOPIC_0000001145510991__i11527155911457">{password}</em>';
ALTER SESSION SET SESSION AUTHORIZATION joe PASSWORD '<em id="EN-US_TOPIC_0000001145510991__i1825553434817">{password}</em>';</pre>
<p id="EN-US_TOPIC_0000001145510991__p44481011102110">Switch to the default user.</p>
<pre class="screen" id="EN-US_TOPIC_0000001145510991__screen885411307312">ALTER SESSION SET SESSION AUTHORIZATION default;</pre>
<p id="EN-US_TOPIC_0000001145510991__p244731112116"></p>
</div>
<div class="section" id="EN-US_TOPIC_0000001145510991__sa427c8fd0e23481ba0ff89ec7361782f"><h4 class="sectiontitle">Helpful Links</h4><p id="EN-US_TOPIC_0000001145510991__a3f81ee95a4ac4e618d597a92fa80785f"><a href="dws_06_0220.html">SET</a></p>
</div>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_06_0118.html">DDL Syntax</a></div>
</div>
</div>
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