(PHP 5)
mysqli::$field_count -- mysqli_field_count — Returns the number of columns for the most recent query
面向对象风格
过程化风格
Returns the number of columns for the most recent query on the connection
represented by the link parameter. This function
can be useful when using the mysqli_store_result()
function to determine if the query should have produced a non-empty result
set or not without knowing the nature of the query.
An integer representing the number of fields in a result set.
Example #1 $mysqli->field_count example
面向对象风格
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "test");
$mysqli->query( "DROP TABLE IF EXISTS friends");
$mysqli->query( "CREATE TABLE friends (id int, name varchar(20))");
$mysqli->query( "INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')");
$mysqli->real_query("SELECT * FROM friends");
if ($mysqli->field_count) {
/* this was a select/show or describe query */
$result = $mysqli->store_result();
/* process resultset */
$row = $result->fetch_row();
/* free resultset */
$result->close();
}
/* close connection */
$mysqli->close();
?>
过程化风格
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "test");
mysqli_query($link, "DROP TABLE IF EXISTS friends");
mysqli_query($link, "CREATE TABLE friends (id int, name varchar(20))");
mysqli_query($link, "INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')");
mysqli_real_query($link, "SELECT * FROM friends");
if (mysqli_field_count($link)) {
/* this was a select/show or describe query */
$result = mysqli_store_result($link);
/* process resultset */
$row = mysqli_fetch_row($result);
/* free resultset */
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
Jonathan (2007-03-06 03:43:14)
Some corrections ;o)
$mysqli_type = array();
$mysqli_type[0] = "DECIMAL";
$mysqli_type[1] = "TINYINT";
$mysqli_type[2] = "SMALLINT";
$mysqli_type[3] = "INTEGER";
$mysqli_type[4] = "FLOAT";
$mysqli_type[5] = "DOUBLE";
$mysqli_type[7] = "TIMESTAMP";
$mysqli_type[8] = "BIGINT";
$mysqli_type[9] = "MEDIUMINT";
$mysqli_type[10] = "DATE";
$mysqli_type[11] = "TIME";
$mysqli_type[12] = "DATETIME";
$mysqli_type[13] = "YEAR";
$mysqli_type[14] = "DATE";
$mysqli_type[16] = "BIT";
$mysqli_type[246] = "DECIMAL";
$mysqli_type[247] = "ENUM";
$mysqli_type[248] = "SET";
$mysqli_type[249] = "TINYBLOB";
$mysqli_type[250] = "MEDIUMBLOB";
$mysqli_type[251] = "LONGBLOB";
$mysqli_type[252] = "BLOB";
$mysqli_type[253] = "VARCHAR";
$mysqli_type[254] = "CHAR";
$mysqli_type[255] = "GEOMETRY";
Typer85 at gmail dot com (2007-01-02 08:33:56)
For those interested and to clarify the Manual Entry.
For query statements that are DESIGNED to return a result set of some sort, this function will always return the number of fields in the table that was queried.
I said DESIGNED because the return value has no effect on whether or not the actual query matched any rows or not.
For example, say I have a table that has 2 fields and only 10 rows. I issue the following query:
<?php
// Assume Connection Blah Blah.
mysqli_query( $connObject , "Select * From `table` Where `Id` > 1000");
// Get Number Of Fields.
mysqli_field_count( $connObject );
// Will Return 2 --> The Number of fields in the table!
?>
It is quite clear that the query itself will never return a result set because I asked it to return rows which have an Id over 1000 and there are only 10 rows.
But because the nature of the query itself is to return a result set, the field count is always returned no matter what.
In contrast, if the query does anything that does not return a result set by nature, such as an insert or update, the field count will always be 0.
Hence, you can easily determine the nature of this query dynamically using these return values.
Good Luck,
?>
dedlfix (2006-07-18 10:26:29)
There are MYSQLI_TYPE_* constants for the type property (listed in http://php.net/manual/en/ref.mysqli.php).
e.g.
<?php
if ($finfo->type == MYSQLI_TYPE_VAR_STRING)
// a VARCHAR
jakerosoft at hotmail dot com (2005-08-16 09:15:38)
<?
$fieldinfo = $result->fetch_field();
if ($fieldinfo & MYSQLI_NOT_NULL_FLAG) {
print "not null flag is set";
} else {
print "not null flag is NOT set";
}
?>
(2005-07-07 15:56:52)
The "type" property will return a numerical representation of a field type instead of a "meaningful" string.
Here is an array that may help you:
<?php
$mysqli_type = array();
$mysqli_type[0] = "decimal";
$mysqli_type[1] = "tinyint";
$mysqli_type[2] = "smallint";
$mysqli_type[3] = "int";
$mysqli_type[4] = "float";
$mysqli_type[5] = "double";
$mysqli_type[7] = "timestamp";
$mysqli_type[8] = "bigint";
$mysqli_type[9] = "mediumint";
$mysqli_type[10] = "date";
$mysqli_type[11] = "time";
$mysqli_type[12] = "datetime";
$mysqli_type[13] = "year";
$mysqli_type[252] = "blob"; // text, blob, tinyblob,mediumblob, etc...
$mysqli_type[253] = "string"; // varchar and char
$mysqli_type[254] = "enum";
?>