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
|
<?xml version="1.0" encoding="UTF-8"?>
<refentry version="5.0-subset Scilab" xml:id="mysql_fetch_field" xml:lang="en"
xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:svg="http://www.w3.org/2000/svg"
xmlns:ns3="http://www.w3.org/1999/xhtml"
xmlns:mml="http://www.w3.org/1998/Math/MathML"
xmlns:db="http://docbook.org/ns/docbook">
<refnamediv>
<refname>mysql_fetch_field</refname>
<refpurpose>Returns the definition of one column of a result set as a plist mlist.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Calling Sequence</title>
<synopsis>mysql_field = mysql_fetch_field(mysql_res)</synopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
<para>Returns the definition of one column of a result set as a plist mlist.</para>
<para>Call this function repeatedly to retrieve information about
all columns in the result set.</para>
<para><literal>mysql_fetch_field</literal> returns empty when no more fields are left.</para>
<para><literal>mysql_fetch_field</literal> is reset to return information
about the first field each time you execute a new <literal>SELECT</literal> query.</para>
<para>The field returned by <literal>mysql_fetch_field</literal>
is also affected by calls to <literal>mysql_field_seek</literal>.</para>
<para>If you've called <literal>mysql_query</literal> to perform a
<literal>SELECT</literal> on a table but have not called
<literal>mysql_store_result</literal>, MySQL returns the default blob
length (8KB) if you call <literal>mysql_fetch_field</literal> to ask for the length
of a BLOB field. (The 8KB size is chosen because MySQL doesn't
know the maximum length for the BLOB. This should be made
configurable sometime). Once you've retrieved the result set,
field->max_length contains the length of the largest value for
this column in the specific query.</para>
</refsection>
<refsection>
<title>Parameters</title>
<variablelist>
<varlistentry>
<term>mysql_res</term>
<listitem>
<para>a MySQL_RES pointer</para>
</listitem>
</varlistentry>
<varlistentry>
<term>mysql_field</term>
<listitem>
<para>a plist mlist (a mlist that can be managed using the
parameter toolbox) which contains all the MYSQL_FIELD fields.</para>
</listitem>
</varlistentry>
</variablelist>
</refsection>
<refsection>
<title>Examples</title>
<programlisting role="example"><![CDATA[
username = 'glpk'; // Put your username
password = 'gnu'; // Put your password
database = 'glpk';
port = 3306; // use netstat -a | grep mysql to locate the mysql port
// or ps -elf | grep mysql and locate --port
myhost = 'localhost'; // localhost most of the time
sql_ptr = mysql_init();
status = mysql_real_connect(sql_ptr, myhost, username, password, database, port);
sql = sprintf("select val from sudoku where val>=0 and val<7;\n");
status = mysql_real_query(sql_ptr, sql);
rs = mysql_store_result(sql_ptr);
res = mysql_fetch_field(rs);
disp(res);
mysql_free_result(rs);
mysql_close(sql_ptr);
]]></programlisting>
</refsection>
<refsection>
<title>See Also</title>
<simplelist type="inline">
<member><link linkend="mysql_init">mysql_init</link></member>
<member><link linkend="mysql_real_connect">mysql_real_connect</link></member>
<member><link linkend="mysql_real_query">mysql_real_query</link></member>
<member><link linkend="mysql_close">mysql_close</link></member>
<member><link linkend="mysql_free_result">mysql_free_result</link></member>
<member><link linkend="mysql_store_result">mysql_store_result</link></member>
</simplelist>
</refsection>
<refsection>
<title>Authors</title>
<simplelist type="vert">
<member>Yann COLLETTE</member>
</simplelist>
</refsection>
</refentry>
|
