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- You can create a new table by specifying the table
- name, along with all column names and their types:
-
- </p><pre class="programlisting">
- CREATE TABLE weather (
- city varchar(80),
- temp_lo int, -- low temperature
- temp_hi int, -- high temperature
- prcp real, -- precipitation
- date date
- );
- </pre><p>
-
- You can enter this into <code class="command">psql</code> with the line
- breaks. <code class="command">psql</code> will recognize that the command
- is not terminated until the semicolon.
- </p><p>
- White space (i.e., spaces, tabs, and newlines) can be used freely
- in SQL commands. That means you can type the command aligned
- differently than above, or even all on one line. Two dashes
- (<span class="quote">“<span class="quote"><code class="literal">--</code></span>”</span>) introduce comments.
- Whatever follows them is ignored up to the end of the line. SQL
- is case insensitive about key words and identifiers, except
- when identifiers are double-quoted to preserve the case (not done
- above).
- </p><p>
- <code class="type">varchar(80)</code> specifies a data type that can store
- arbitrary character strings up to 80 characters in length.
- <code class="type">int</code> is the normal integer type. <code class="type">real</code> is
- a type for storing single precision floating-point numbers.
- <code class="type">date</code> should be self-explanatory. (Yes, the column of
- type <code class="type">date</code> is also named <code class="structfield">date</code>.
- This might be convenient or confusing — you choose.)
- </p><p>
- <span class="productname">PostgreSQL</span> supports the standard
- <acronym class="acronym">SQL</acronym> types <code class="type">int</code>,
- <code class="type">smallint</code>, <code class="type">real</code>, <code class="type">double
- precision</code>, <code class="type">char(<em class="replaceable"><code>N</code></em>)</code>,
- <code class="type">varchar(<em class="replaceable"><code>N</code></em>)</code>, <code class="type">date</code>,
- <code class="type">time</code>, <code class="type">timestamp</code>, and
- <code class="type">interval</code>, as well as other types of general utility
- and a rich set of geometric types.
- <span class="productname">PostgreSQL</span> can be customized with an
- arbitrary number of user-defined data types. Consequently, type
- names are not key words in the syntax, except where required to
- support special cases in the <acronym class="acronym">SQL</acronym> standard.
- </p><p>
- The second example will store cities and their associated
- geographical location:
- </p><pre class="programlisting">
- CREATE TABLE cities (
- name varchar(80),
- location point
- );
- </pre><p>
- The <code class="type">point</code> type is an example of a
- <span class="productname">PostgreSQL</span>-specific data type.
- </p><p>
- <a id="id-1.4.4.4.8.1" class="indexterm"></a>
-
- Finally, it should be mentioned that if you don't need a table any
- longer or want to recreate it differently you can remove it using
- the following command:
- </p><pre class="synopsis">
- DROP TABLE <em class="replaceable"><code>tablename</code></em>;
- </pre><p>
- </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="tutorial-concepts.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="tutorial-sql.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="tutorial-populate.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">2.2. Concepts </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> 2.4. Populating a Table With Rows</td></tr></table></div></body></html>
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