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Tom Lane 2003-11-05 00:05:32 +00:00
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doc/src/sgml/ddl.sgml
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<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ddl.sgml,v 1.22 2003/11/04 09:55:38 petere Exp $ --> <!-- $Header: /cvsroot/pgsql/doc/src/sgml/ddl.sgml,v 1.23 2003/11/05 00:05:32 tgl Exp $ -->
<chapter id="ddl"> <chapter id="ddl">
<title>Data Definition</title> <title>Data Definition</title>
@ -12,8 +12,7 @@
Subsequently, we discuss how tables can be organized into Subsequently, we discuss how tables can be organized into
schemas, and how privileges can be assigned to tables. Finally, schemas, and how privileges can be assigned to tables. Finally,
we will briefly look at other features that affect the data storage, we will briefly look at other features that affect the data storage,
such as views, functions, and triggers. Detailed information on such as views, functions, and triggers.
these topics is found in <xref linkend="server-programming">.
</para> </para>
<sect1 id="ddl-basics"> <sect1 id="ddl-basics">
@ -522,7 +521,7 @@ CREATE TABLE products (
<para> <para>
It should be noted that a check constraint is satisfied if the It should be noted that a check constraint is satisfied if the
check expression evaluates to true or the null value. Since most check expression evaluates to true or the null value. Since most
expressions will evaluate to the null value if one operand is null expressions will evaluate to the null value if one operand is null,
they will not prevent null values in the constrained columns. To they will not prevent null values in the constrained columns. To
ensure that a column does not contain null values, the not-null ensure that a column does not contain null values, the not-null
constraint described in the next section should be used. constraint described in the next section should be used.
@ -586,7 +585,7 @@ CREATE TABLE products (
The <literal>NULL</literal> constraint is not defined in the SQL The <literal>NULL</literal> constraint is not defined in the SQL
standard and should not be used in portable applications. (It was standard and should not be used in portable applications. (It was
only added to <productname>PostgreSQL</productname> to be only added to <productname>PostgreSQL</productname> to be
compatible with other database systems.) Some users, however, compatible with some other database systems.) Some users, however,
like it because it makes it easy to toggle the constraint in a like it because it makes it easy to toggle the constraint in a
script file. For example, you could start with script file. For example, you could start with
<programlisting> <programlisting>
@ -820,7 +819,7 @@ CREATE TABLE orders (
); );
</programlisting> </programlisting>
because in absence of a column list the primary key of the because in absence of a column list the primary key of the
referenced table is used as referenced column. referenced table is used as the referenced column.
</para> </para>
<para> <para>
@ -1094,9 +1093,10 @@ WHERE c.altitude &gt; 500 and c.tableoid = p.oid;
<title>Deprecated</title> <title>Deprecated</title>
<para> <para>
In previous versions of <productname>PostgreSQL</productname>, the In previous versions of <productname>PostgreSQL</productname>, the
default was not to get access to child tables. This was found to default behavior was not to include child tables in queries. This was
be error prone and is also in violation of the SQL99 standard. Under the old found to be error prone and is also in violation of the SQL99
syntax, to get the sub-tables you append <literal>*</literal> to the table name. standard. Under the old syntax, to get the sub-tables you append
<literal>*</literal> to the table name.
For example For example
<programlisting> <programlisting>
SELECT * from cities*; SELECT * from cities*;
@ -1270,6 +1270,12 @@ ALTER TABLE products ALTER COLUMN product_no SET NOT NULL;
<programlisting> <programlisting>
ALTER TABLE products DROP CONSTRAINT some_name; ALTER TABLE products DROP CONSTRAINT some_name;
</programlisting> </programlisting>
(If you are dealing with a generated constraint name like <literal>$2</>,
don't forget that you'll need to double-quote it to make it a valid
identifier.)
</para>
<para>
This works the same for all constraint types except not-null This works the same for all constraint types except not-null
constraints. To drop a not null constraint use constraints. To drop a not null constraint use
<programlisting> <programlisting>
@ -1739,9 +1745,11 @@ SELECT 3 OPERATOR(pg_catalog.+) 4;
A user can also be allowed to create objects in someone else's A user can also be allowed to create objects in someone else's
schema. To allow that, the <literal>CREATE</literal> privilege on schema. To allow that, the <literal>CREATE</literal> privilege on
the schema needs to be granted. Note that by default, everyone the schema needs to be granted. Note that by default, everyone
has the <literal>CREATE</literal> privilege on the schema has <literal>CREATE</literal> and <literal>USAGE</literal> privileges on
<literal>public</literal>. This allows all users that manage to the schema
connect to a given database to create objects there. If you do <literal>public</literal>. This allows all users that are able to
connect to a given database to create objects in its
<literal>public</literal> schema. If you do
not want to allow that, you can revoke that privilege: not want to allow that, you can revoke that privilege:
<programlisting> <programlisting>
REVOKE CREATE ON SCHEMA public FROM PUBLIC; REVOKE CREATE ON SCHEMA public FROM PUBLIC;
@ -1905,6 +1913,11 @@ REVOKE CREATE ON SCHEMA public FROM PUBLIC;
</para> </para>
</listitem> </listitem>
</itemizedlist> </itemizedlist>
<para>
Detailed information on
these topics appears in <xref linkend="server-programming">.
</para>
</sect1> </sect1>
<sect1 id="ddl-depend"> <sect1 id="ddl-depend">