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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244
|
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>31.16.element_types</title>
<link rel="stylesheet" href="stylesheet.css" type="text/css">
<link rev="made" href="pgsql-docs@postgresql.org">
<meta name="generator" content="DocBook XSL Stylesheets V1.70.0">
<link rel="start" href="index.html" title="PostgreSQL 8.1.4 Documentation">
<link rel="up" href="information-schema.html" title="Chapter31.The Information Schema">
<link rel="prev" href="infoschema-domains.html" title="31.15.domains">
<link rel="next" href="infoschema-enabled-roles.html" title="31.17.enabled_roles">
<link rel="copyright" href="ln-legalnotice.html" title="Legal Notice">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="sect1" lang="en">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="infoschema-element-types"></a>31.16.<code class="literal">element_types</code></h2></div></div></div>
<p> The view <code class="literal">element_types</code> contains the data type
descriptors of the elements of arrays. When a table column,
domain, function parameter, or function return value is defined to
be of an array type, the respective information schema view only
contains <code class="literal">ARRAY</code> in the column
<code class="literal">data_type</code>. To obtain information on the element
type of the array, you can join the respective view with this view.
For example, to show the columns of a table with data types and
array element types, if applicable, you could do
</p>
<pre class="programlisting">SELECT c.column_name, c.data_type, e.data_type AS element_type
FROM information_schema.columns c LEFT JOIN information_schema.element_types e
ON ((c.table_catalog, c.table_schema, c.table_name, 'TABLE', c.dtd_identifier)
= (e.object_catalog, e.object_schema, e.object_name, e.object_type, e.array_type_identifier))
WHERE c.table_schema = '...' AND c.table_name = '...'
ORDER BY c.ordinal_position;</pre>
<p>
This view only includes objects that the current user has access
to, by way of being the owner or having some privilege.
</p>
<div class="table">
<a name="id696110"></a><p class="title"><b>Table31.14.<code class="literal">element_types</code> Columns</b></p>
<div class="table-contents"><table summary="element_types Columns" border="1">
<colgroup>
<col>
<col>
<col>
</colgroup>
<thead><tr>
<th>Name</th>
<th>Data Type</th>
<th>Description</th>
</tr></thead>
<tbody>
<tr>
<td><code class="literal">object_catalog</code></td>
<td><code class="type">sql_identifier</code></td>
<td> Name of the database that contains the object that uses the
array being described (always the current database)
</td>
</tr>
<tr>
<td><code class="literal">object_schema</code></td>
<td><code class="type">sql_identifier</code></td>
<td> Name of the schema that contains the object that uses the array
being described
</td>
</tr>
<tr>
<td><code class="literal">object_name</code></td>
<td><code class="type">sql_identifier</code></td>
<td> Name of the object that uses the array being described
</td>
</tr>
<tr>
<td><code class="literal">object_type</code></td>
<td><code class="type">character_data</code></td>
<td> The type of the object that uses the array being described: one
of <code class="literal">TABLE</code> (the array is used by a column of
that table), <code class="literal">DOMAIN</code> (the array is used by
that domain), <code class="literal">ROUTINE</code> (the array is used by
a parameter or the return data type of that function).
</td>
</tr>
<tr>
<td><code class="literal">array_type_identifier</code></td>
<td><code class="type">sql_identifier</code></td>
<td> The identifier of the data type descriptor of the array being
described. Use this to join with the
<code class="literal">dtd_identifier</code> columns of other information
schema views.
</td>
</tr>
<tr>
<td><code class="literal">data_type</code></td>
<td><code class="type">character_data</code></td>
<td> Data type of the array elements, if it is a built-in type, else
<code class="literal">USER-DEFINED</code> (in that case, the type is
identified in <code class="literal">udt_name</code> and associated
columns).
</td>
</tr>
<tr>
<td><code class="literal">character_maximum_length</code></td>
<td><code class="type">cardinal_number</code></td>
<td>Always null, since this information is not applied to array element data types in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">character_octet_length</code></td>
<td><code class="type">cardinal_number</code></td>
<td>Always null, since this information is not applied to array element data types in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">character_set_catalog</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Applies to a feature not available in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">character_set_schema</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Applies to a feature not available in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">character_set_name</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Applies to a feature not available in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">collation_catalog</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Applies to a feature not available in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">collation_schema</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Applies to a feature not available in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">collation_name</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Applies to a feature not available in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">numeric_precision</code></td>
<td><code class="type">cardinal_number</code></td>
<td>Always null, since this information is not applied to array element data types in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">numeric_precision_radix</code></td>
<td><code class="type">cardinal_number</code></td>
<td>Always null, since this information is not applied to array element data types in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">numeric_scale</code></td>
<td><code class="type">cardinal_number</code></td>
<td>Always null, since this information is not applied to array element data types in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">datetime_precision</code></td>
<td><code class="type">cardinal_number</code></td>
<td>Always null, since this information is not applied to array element data types in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">interval_type</code></td>
<td><code class="type">character_data</code></td>
<td>Always null, since this information is not applied to array element data types in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">interval_precision</code></td>
<td><code class="type">character_data</code></td>
<td>Always null, since this information is not applied to array element data types in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">domain_default</code></td>
<td><code class="type">character_data</code></td>
<td>Not yet implemented</td>
</tr>
<tr>
<td><code class="literal">udt_catalog</code></td>
<td><code class="type">sql_identifier</code></td>
<td> Name of the database that the data type of the elements is
defined in (always the current database)
</td>
</tr>
<tr>
<td><code class="literal">udt_schema</code></td>
<td><code class="type">sql_identifier</code></td>
<td> Name of the schema that the data type of the elements is
defined in
</td>
</tr>
<tr>
<td><code class="literal">udt_name</code></td>
<td><code class="type">sql_identifier</code></td>
<td> Name of the data type of the elements
</td>
</tr>
<tr>
<td><code class="literal">scope_catalog</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Applies to a feature not available in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">scope_schema</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Applies to a feature not available in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">scope_name</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Applies to a feature not available in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">maximum_cardinality</code></td>
<td><code class="type">cardinal_number</code></td>
<td>Always null, because arrays always have unlimited maximum cardinality in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">dtd_identifier</code></td>
<td><code class="type">sql_identifier</code></td>
<td> An identifier of the data type descriptor of the element. This
is currently not useful.
</td>
</tr>
</tbody>
</table></div>
</div>
<br class="table-break">
</div></body>
</html>
|