翻译 hstore.sgml

Author: sizhitu

postgresql/doc/src/sgml/hstore.sgml

@@ -620,21 +620,6 @@ ____________________________________________________________________________-->
     </tgroup>
   </table>
 
-  <note>
-<!--==========================orignal english content==========================
-  <para>
-   Prior to PostgreSQL 8.2, the containment operators <literal>@&gt;</literal>
-   and <literal>&lt;@</literal> were called <literal>@</literal> and <literal>~</literal>,
-   respectively. These names are still available, but are deprecated and will
-   eventually be removed. Notice that the old names are reversed from the
-   convention formerly followed by the core geometric data types!
-   </para>
-____________________________________________________________________________-->
-  <para>
-   在 PostgreSQL 8.2 之前，包含操作符<literal>@&gt;</literal>和<literal>&lt;@</literal>分别被称为<literal>@</literal>和<literal>~</literal>。这些名称仍然可用，但是已经被弃用并且最终将被移除。注意，旧名称和原来核心几何数据类型所遵循的习惯是相反的！
-   </para>
-  </note>
-
   <table id="hstore-func-table">
 <!--==========================orignal english content==========================
    <title><type>hstore</type> Functions</title>
@@ -1409,6 +1394,27 @@ ____________________________________________________________________________-->
     </tbody>
    </tgroup>
   </table>
+
+  <para>
+  除了这个运算符和函数之外，<type>hstore</type>类型的值可以被索引，在这种情况下它们的行为就像关联数组。 <type>text</type>只允许该类型的单个下标。下标被解释为一个键，并检索或存储相应的值。例如:
+<programlisting>
+CREATE TABLE mytable (h hstore);
+INSERT INTO mytable VALUES ('a=>b, c=>d');
+SELECT h['a'] FROM mytable;
+ h
+---
+ b
+(1 row)
+
+UPDATE mytable SET h['c'] = 'new';
+SELECT h FROM mytable;
+          h
+----------------------
+ "a"=>"b", "c"=>"new"
+(1 row)
+</programlisting>
+如果索引是<literal>NULL</literal>，或者索引<type>hstore</type>中不存在键，则按索引获取<literal>NULL</literal>返回 。（所以下标检索<literal>-&gt;</literal>和算子区别不大。）如果下标是<literal>NULL</literal> ，则下标更新失败。否则，替换与该键对应的值<type>hstore</type>，如果该键不存在，则添加一个条目。
+  </para>
  </sect2>
 
  <sect2>
@@ -1516,7 +1522,15 @@ ____________________________________________________________________________-->
   <para>
    增加一个键，或者用一个新值更新一个现有的键：
 <programlisting>
+UPDATE tab SET h['c'] = '3';
+</programlisting>
+   另一种方法:
+<programlisting>
 UPDATE tab SET h = h || hstore('c', '3');
+</programlisting>
+   在单个操作中添加或修改多个键时，连接比下标更高效:
+<programlisting>
+UPDATE tab SET h = h || hstore(array['q', 'w'], array['11', '12']);
 </programlisting>
   </para>
 
@@ -1667,7 +1681,7 @@ ____________________________________________________________________________-->
   <para>
    使用一个表：
 <programlisting>
-SELECT (each(h)).key, (each(h)).value INTO stat FROM testhstore;
+CREATE TABLE stat AS SELECT (each(h)).key, (each(h)).value FROM testhstore;
 </programlisting>
   </para>
 
@@ -1769,7 +1783,7 @@ ____________________________________________________________________________-->
 <programlisting>
 ALTER TABLE tablename ALTER hstorecol TYPE hstore USING hstorecol || '';
 </programlisting>
-   <command>ALTER TABLE</command>方法要求表上的一个排他锁，但是不会导致表因为旧行版本而膨胀。
+   <command>ALTER TABLE</command>方法要求表上的一个<literal>ACCESS EXCLUSIVE</literal> 锁，但是不会导致表因为旧行版本而膨胀。
   </para>
 
  </sect2>