mysql_fetch_field
(PHP 4, PHP 5)
mysql_fetch_field — 从结果集中取得列信息并作为对象返回
说明
object <strong>mysql_fetch_field</strong>
( resource <code>$result</code>
[, int <code>$field_offset</code>
] )
<p>
返回一个包含字段信息的对象。
</p>
<p>
<strong>mysql_fetch_field()</strong>
可以用来从某个查询结果中取得字段的信息。如果没有指定字段偏移量,则下一个尚未被
<strong>mysql_fetch_field()</strong> 取得的字段被提取。
</p>
<p>
对象的属性为:
name - 列名
table - 该列所在的表名
max_length - 该列最大长度
not_null - 1,如果该列不能为 <strong><code>NULL</code></strong>
primary_key - 1,如果该列是 primary key
unique_key - 1,如果该列是 unique key
multiple_key - 1,如果该列是 non-unique key
numeric - 1,如果该列是 numeric
blob - 1,如果该列是 BLOB
type - 该列的类型
unsigned - 1,如果该列是无符号数
zerofill - 1,如果该列是 zero-filled
</p>
<p><strong>Note</strong>: 此函数返回的字段名大小写敏感。</p>
<p>
<p><strong>Example #1 <strong>mysql_fetch_field()</strong></strong></p>
<?php
mysql_connect('localhost:3306', $user, $password)
or die("Could not connect: " . mysql_error());
mysql_select_db("database");
$result = mysql_query("select * from table")
or die("Query failed: " . mysql_error());
/* get column metadata */
$i = 0;
while ($i < mysql_num_fields($result)) {
echo "Information for column $i:<br />n";
$meta = mysql_fetch_field($result);
if (!$meta) {
echo "No information available<br />n";
}
echo "<pre>
blob: $meta->blob
max_length: $meta->max_length
multiple_key: $meta->multiple_key
name: $meta->name
not_null: $meta->not_null
numeric: $meta->numeric
primary_key: $meta->primary_key
table: $meta->table
type: $meta->type
unique_key: $meta->unique_key
unsigned: $meta->unsigned
zerofill: $meta->zerofill
</pre>";
$i++;
}
mysql_free_result($result);
?>
</p>
<p>
参见 mysql_field_seek()。
</p>
参数
result
resource 型的结果集。此结果集来自对 mysql_query() 的调用。
field_offset
The numerical field offset. If the field offset is not specified, the
next field that was not yet retrieved by this function is retrieved.
The field_offset
starts at 0.
返回值
Returns an object containing field information. The properties of the object are:
name - column name
table - name of the table the column belongs to
max_length - maximum length of the column
not_null - 1 if the column cannot be NULL
primary_key - 1 if the column is a primary key
unique_key - 1 if the column is a unique key
multiple_key - 1 if the column is a non-unique key
numeric - 1 if the column is numeric
blob - 1 if the column is a BLOB
type - the type of the column
unsigned - 1 if the column is unsigned
zerofill - 1 if the column is zero-filled
范例
Example #2 mysql_fetch_field() example
<?php
$conn = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$conn) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db('database');
$result = mysql_query('select * from table');
if (!$result) {
die('Query failed: ' . mysql_error());
}
/* get column metadata */
$i = 0;
while ($i < mysql_num_fields($result)) {
echo "Information for column $i:<br />n";
$meta = mysql_fetch_field($result, $i);
if (!$meta) {
echo "No information available<br />n";
}
echo "<pre>
blob: $meta->blob
max_length: $meta->max_length
multiple_key: $meta->multiple_key
name: $meta->name
not_null: $meta->not_null
numeric: $meta->numeric
primary_key: $meta->primary_key
table: $meta->table
type: $meta->type
unique_key: $meta->unique_key
unsigned: $meta->unsigned
zerofill: $meta->zerofill
</pre>";
$i++;
}
mysql_free_result($result);
?>
注释
Note: 此函数返回的字段名大小写敏感。
参见
mysql_field_seek() - 将结果集中的指针设定为制定的字段偏移量