blob: 6b84902fe1c543e6ddfbe5e28d8d37e72646c614 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
|
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/alter_domain.sgml,v 1.11 2003/11/29 19:51:38 pgsql Exp $
PostgreSQL documentation
-->
<refentry id="SQL-ALTERDOMAIN">
<refmeta>
<refentrytitle id="sql-alterdomain-title">ALTER DOMAIN</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
<refnamediv>
<refname>
ALTER DOMAIN
</refname>
<refpurpose>
change the definition of a domain
</refpurpose>
</refnamediv>
<indexterm zone="sql-alterdomain">
<primary>ALTER DOMAIN</primary>
</indexterm>
<refsynopsisdiv>
<synopsis>
ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable>
{ SET DEFAULT <replaceable class="PARAMETER">expression</replaceable> | DROP DEFAULT }
ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable>
{ SET | DROP } NOT NULL
ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable>
ADD <replaceable class="PARAMETER">domain_constraint</replaceable>
ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable>
DROP CONSTRAINT <replaceable class="PARAMETER">constraint_name</replaceable> [ RESTRICT | CASCADE ]
ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable>
OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
</synopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<command>ALTER DOMAIN</command> changes the definition of an existing domain.
There are several sub-forms:
</para>
<variablelist>
<varlistentry>
<term>SET/DROP DEFAULT</term>
<listitem>
<para>
These forms set or remove the default value for a domain. Note
that defaults only apply to subsequent <command>INSERT</command>
commands; they do not affect rows already in a table using the domain.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SET/DROP NOT NULL</term>
<listitem>
<para>
These forms change whether a domain is marked to allow NULL
values or to reject NULL values. You may only <literal>SET NOT NULL</>
when the columns using the domain contain no null values.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>ADD <replaceable class="PARAMETER">domain_constraint</replaceable></term>
<listitem>
<para>
This form adds a new constraint to a domain using the same syntax as
<xref linkend="SQL-CREATEDOMAIN" endterm="SQL-CREATEDOMAIN-TITLE">.
This will only succeed if all columns using the domain satisfy the
new constraint.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>DROP CONSTRAINT</term>
<listitem>
<para>
This form drops constraints on a domain.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>OWNER</term>
<listitem>
<para>
This form changes the owner of the domain to the specified user.
</para>
</listitem>
</varlistentry>
</variablelist>
<para>
You must own the domain to use <command>ALTER DOMAIN</>; except for
<command>ALTER DOMAIN OWNER</>, which may only be executed by a superuser.
</para>
</refsect1>
<refsect1>
<title>Parameters</title>
<para>
<variablelist>
<varlistentry>
<term><replaceable class="PARAMETER">name</replaceable></term>
<listitem>
<para>
The name (possibly schema-qualified) of an existing domain to
alter.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="PARAMETER">domain_constraint</replaceable></term>
<listitem>
<para>
New domain constraint for the domain.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="PARAMETER">constraint_name</replaceable></term>
<listitem>
<para>
Name of an existing constraint to drop.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>CASCADE</term>
<listitem>
<para>
Automatically drop objects that depend on the constraint.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>RESTRICT</term>
<listitem>
<para>
Refuse to drop the constraint if there are any dependent
objects. This is the default behavior.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="PARAMETER">new_owner</replaceable></term>
<listitem>
<para>
The user name of the new owner of the domain.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1>
<title>Examples</title>
<para>
To add a NOT NULL constraint to a domain:
<programlisting>
ALTER DOMAIN zipcode SET NOT NULL;
</programlisting>
To remove a NOT NULL constraint from a domain:
<programlisting>
ALTER DOMAIN zipcode DROP NOT NULL;
</programlisting>
</para>
<para>
To add a check constraint to a domain:
<programlisting>
ALTER DOMAIN zipcode ADD CONSTRAINT zipchk CHECK (char_length(VALUE) = 5);
</programlisting>
</para>
<para>
To remove a check constraint from a domain:
<programlisting>
ALTER DOMAIN zipcode DROP CONSTRAINT zipchk;
</programlisting>
</para>
</refsect1>
<refsect1>
<title>Compatibility</title>
<para>
The <command>ALTER DOMAIN</command> statement is compatible with SQL99,
except for the <literal>OWNER</> variant, which is a
<productname>PostgreSQL</productname> extension.
</para>
</refsect1>
</refentry>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:nil
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
sgml-parent-document:nil
sgml-default-dtd-file:"../reference.ced"
sgml-exposed-tags:nil
sgml-local-catalogs:"/usr/lib/sgml/catalog"
sgml-local-ecat-files:nil
End:
-->
|
