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<!--
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$Header: /cvsroot/pgsql/doc/src/sgml/advanced.sgml,v 1.25 2001/11/21 05:53:40 thomas Exp $
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$Header: /cvsroot/pgsql/doc/src/sgml/advanced.sgml,v 1.26 2001/11/23 21:08:51 tgl Exp $
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-->
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<chapter id="tutorial-advanced">
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@ -132,7 +132,7 @@ ERROR: <unnamed> referential integrity violation - key referenced from we
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<para>
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The behavior of foreign keys can be finely tuned to your
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application. We will not go beyond this simple example in this
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tutorial and refer you to the <citetitle>Reference
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tutorial, but just refer you to the <citetitle>Reference
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Manual</citetitle> for more information. Making correct use of
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foreign keys will definitely improve the quality of your database
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applications, so you are strongly encouraged to learn about them.
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@ -1,5 +1,5 @@
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<!--
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$Header: /cvsroot/pgsql/doc/src/sgml/query.sgml,v 1.21 2001/11/19 05:37:53 tgl Exp $
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$Header: /cvsroot/pgsql/doc/src/sgml/query.sgml,v 1.22 2001/11/23 21:08:51 tgl Exp $
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-->
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<chapter id="tutorial-sql">
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@ -15,8 +15,8 @@ $Header: /cvsroot/pgsql/doc/src/sgml/query.sgml,v 1.21 2001/11/19 05:37:53 tgl E
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way a complete tutorial on <acronym>SQL</acronym>. Numerous books
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have been written on <acronym>SQL92</acronym>, including <xref
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linkend="MELT93"> and <xref linkend="DATE97">.
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You should be aware that some language
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features are extensions to the standard.
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You should be aware that some <productname>PostgreSQL</productname>
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language features are extensions to the standard.
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</para>
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<para>
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@ -44,7 +44,7 @@ $Header: /cvsroot/pgsql/doc/src/sgml/query.sgml,v 1.21 2001/11/19 05:37:53 tgl E
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The <literal>\i</literal> command reads in commands from the
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specified file. The <literal>-s</literal> option puts you in
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single step mode which pauses before sending a query to the
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single step mode which pauses before sending each query to the
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server. The commands used in this section are in the file
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<filename>basics.sql</filename>.
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</para>
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@ -78,11 +78,12 @@ $Header: /cvsroot/pgsql/doc/src/sgml/query.sgml,v 1.21 2001/11/19 05:37:53 tgl E
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<indexterm><primary>column</primary></indexterm>
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Each table is a named collection of <firstterm>rows</firstterm>.
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Each row has the same set of named <firstterm>columns</firstterm>,
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Each row of a given table has the same set of named
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<firstterm>columns</firstterm>,
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and each column is of a specific data type. Whereas columns have
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a fixed order in each row, it is important to remember that SQL
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does not guarantee the order of the rows within the table in any
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way (unless they are explicitly sorted).
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way (although they can be explicitly sorted for display).
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</para>
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<para>
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@ -200,7 +201,10 @@ DROP TABLE <replaceable>tablename</replaceable>;
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INSERT INTO weather VALUES ('San Francisco', 46, 50, 0.25, '1994-11-27');
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</programlisting>
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Note that all data types use rather obvious input formats. The
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Note that all data types use rather obvious input formats.
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Constants that are not simple numeric values usually must be
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surrounded by single quotes (<literal>'</>), as in the example.
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The
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<type>date</type> column is actually quite flexible in what it
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accepts, but for this tutorial we will stick to the unambiguous
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format shown here.
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@ -223,7 +227,7 @@ INSERT INTO weather (city, temp_lo, temp_hi, prcp, date)
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VALUES ('San Francisco', 43, 57, 0.0, '1994-11-29');
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</programlisting>
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You can list the columns in a different order if you wish or
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even omit some columns, e.g., unknown precipitation:
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even omit some columns, e.g., if the precipitation is unknown:
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<programlisting>
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INSERT INTO weather (date, city, temp_hi, temp_lo)
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VALUES ('1994-11-29', 'Hayward', 54, 37);
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@ -654,7 +658,9 @@ SELECT city, max(temp_lo)
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(2 rows)
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</screen>
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which gives us one output row per city. We can filter these grouped
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which gives us one output row per city. Each aggregate result is
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computed over the table rows matching that city.
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We can filter these grouped
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rows using <literal>HAVING</literal>:
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<programlisting>
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@ -671,8 +677,9 @@ SELECT city, max(temp_lo)
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(1 row)
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</screen>
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which gives us the same results for only the cities that have some
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below-forty readings. Finally, if we only care about cities whose
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which gives us the same results for only the cities that have all
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<literal>temp_lo</> values below forty. Finally, if we only care about
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cities whose
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names begin with <quote><literal>S</literal></quote>, we might do
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<programlisting>
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@ -1,5 +1,5 @@
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<!--
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$Header: /cvsroot/pgsql/doc/src/sgml/start.sgml,v 1.19 2001/11/21 06:09:45 thomas Exp $
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$Header: /cvsroot/pgsql/doc/src/sgml/start.sgml,v 1.20 2001/11/23 21:08:51 tgl Exp $
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-->
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<chapter id="tutorial-start">
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@ -160,7 +160,7 @@ $Header: /cvsroot/pgsql/doc/src/sgml/start.sgml,v 1.19 2001/11/21 06:09:45 thoma
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<screen>
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CREATE DATABASE
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</screen>
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Is so, this step was successful and you can skip over the
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If so, this step was successful and you can skip over the
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remainder of this section.
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</para>
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@ -173,7 +173,7 @@ createdb: command not found
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installed at all or the search path was not set correctly. Try
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calling the command with an absolute path instead:
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<screen>
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<prompt>$</prompt> <userinput>/usr/local/pgsql/bin/createdb</userinput>
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<prompt>$</prompt> <userinput>/usr/local/pgsql/bin/createdb mydb</userinput>
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</screen>
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The path at your site might be different. Contact your site
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administrator or check back in the installation instructions to
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@ -249,7 +249,7 @@ createdb: database creation failed
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<screen>
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<prompt>$</prompt> <userinput>dropdb mydb</userinput>
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</screen>
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(In this case, the database name does not default to the user
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(For this command, the database name does not default to the user
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account name. You always need to specify it.) This action
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physically removes all files associated with the database and
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cannot be undone, so this should only be done with a great deal of
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