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Code review for DOMAIN patch.

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This commit is contained in:
Tom Lane
2002-03-20 19:45:13 +00:00
parent 251282d4b7
commit 337b22cb47
37 changed files with 869 additions and 850 deletions
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44
doc/src/sgml/ref/create_domain.sgml
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@@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_domain.sgml,v 1.3 2002/03/19 02:18:13 momjian Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_domain.sgml,v 1.4 2002/03/20 19:43:28 tgl Exp $
PostgreSQL documentation
-->
@@ -23,13 +23,14 @@ PostgreSQL documentation
<date>2002-02-24</date>
</refsynopsisdivinfo>
<synopsis>
CREATE DOMAIN <replaceable class="parameter">domainname</replaceable> <replaceable class="parameter">data_type</replaceable> [ DEFAULT <replaceable>default_expr</> ] [ <replaceable class="PARAMETER">column_constraint</replaceable> [, ... ] ]
CREATE DOMAIN <replaceable class="parameter">domainname</replaceable> [AS] <replaceable class="parameter">data_type</replaceable>
[ DEFAULT <replaceable>default_expr</> ]
[ <replaceable class="PARAMETER">constraint</replaceable> [, ... ] ]
where <replaceable class="PARAMETER">constraint</replaceable> is:
[ CONSTRAINT <replaceable class="PARAMETER">constraint_name</replaceable> ]
{ NOT NULL | NULL <!-- | UNIQUE | PRIMARY KEY |
CHECK (<replaceable class="PARAMETER">expression</replaceable>) |
REFERENCES <replaceable class="PARAMETER">reftable</replaceable> [ ( <replaceable class="PARAMETER">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL ]
[ ON DELETE <replaceable class="parameter">action</replaceable> ] [ ON UPDATE <replaceable class="parameter">action</replaceable> ] --> }
<!-- [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ] -->
{ NOT NULL | NULL }
</synopsis>
<refsect2 id="R2-SQL-CREATEDOMAIN-1">
@@ -67,23 +68,26 @@ CREATE DOMAIN <replaceable class="parameter">domainname</replaceable> <replaceab
<replaceable>default_expr</replaceable></literal></term>
<listitem>
<para>
The <literal>DEFAULT</> clause assigns a default data value for
the column whose column definition it appears within. The value
is any variable-free expression (subselects and cross-references
to other columns in the current table are not allowed). The
The <literal>DEFAULT</> clause specifies a default value for
columns of the domain data type. The value
is any variable-free expression (but subselects are not allowed).
The
data type of the default expression must match the data type of the
domain.
</para>
<para>
The default expression will be used in any insert operation that
does not specify a value for the domain. If there is no default
does not specify a value for the column. If there is no default
for a domain, then the default is NULL.
</para>
<note>
<para>
The default of a column will be tested before that of the domain.
If a default value is specified for a particular column, it
overrides any default associated with the domain. In turn,
the domain default overrides any default value associated with
the underlying data type.
</para>
</note>
</listitem>
@@ -93,7 +97,7 @@ CREATE DOMAIN <replaceable class="parameter">domainname</replaceable> <replaceab
<term><literal>CONSTRAINT <replaceable class="PARAMETER">constraint_name</replaceable></literal></term>
<listitem>
<para>
An optional name for a domain. If not specified,
An optional name for a constraint. If not specified,
the system generates a name.
</para>
</listitem>
@@ -103,7 +107,7 @@ CREATE DOMAIN <replaceable class="parameter">domainname</replaceable> <replaceab
<term><literal>NOT NULL</></term>
<listitem>
<para>
The column is not allowed to contain NULL values. This is
Values of this domain are not allowed to be NULL. This is
equivalent to the column constraint <literal>CHECK (<replaceable
class="PARAMETER">column</replaceable> NOT NULL)</literal>.
</para>
@@ -114,7 +118,7 @@ CREATE DOMAIN <replaceable class="parameter">domainname</replaceable> <replaceab
<term><literal>NULL</></term>
<listitem>
<para>
The column is allowed to contain NULL values. This is the default.
Values of this domain are allowed to be NULL. This is the default.
</para>
<para>
@@ -175,7 +179,7 @@ CREATE DOMAIN
Domains are useful for abstracting common fields between tables into
a single location for maintenance. An email address column may be used
in several tables, all with the same properties. Define a domain and
use that rather than setting up each tables constraints individually.
use that rather than setting up each table's constraints individually.
</para>
</refsect1>
@@ -195,9 +199,9 @@ CREATE TABLE countrylist (id INT4, country country_code);
<title>Compatibility</title>
<para>
This <command>CREATE DOMAIN</command> command is a
<productname>PostgreSQL</productname> extension. CHECK and FOREIGN KEY
constraints are currently unsupported.
SQL99 defines CREATE DOMAIN, but says that the only allowed constraint
type is CHECK constraints. CHECK constraints for domains are not yet
supported by <productname>PostgreSQL</productname>.
</para>
</refsect1>