The difference between mysql_fetch_row, mysql_fetch_array, mysql_fetch_assoc_PHP tutorial

Copy code The code is as follows:

$link=mysql_connect('localhost','root'," );
mysql_select_db('abc',$link);
$sql = “select * from book”;
$result = mysql_query($sql);
while($row = mysql_fetch_row( $result))
{
echo $row['cid'].'::'.$row[1].'
';
}
$result = mysql_query( $sql);
while($row = mysql_fetch_array($result))
{
echo $row['cid'].'::'.$row[1].'
';
}
$result = mysql_query($sql);
while($row = mysql_fetch_object($result))
{
echo $row->cid.':: '.$row->title.”
”;
}
$result = mysql_query($sql);
while($row = mysql_fetch_assoc($result))
{
echo $row['cid'].'::'.$row[1].'
';
}
?>

Analysis :
mysql_fetch_row, this function takes a row from the result set as enumeration data, obtains a row of data from the result set associated with the specified result identifier and returns it as an array. The columns of each result are stored in an array unit. The offset starts from 0. Note that the offset here starts from 0, which means that you cannot use the field name to get the value, you can only use the index to get the value, so the following code cannot get the value:
while ($row = mysql_fetch_row($res)){
echo $row['cid'].'::'.$row[1].";
} //$row['cid' here ] Cannot get value.
mysql_fetch_array, gets a row from the result set as an associative array, or a numeric array, or both. In addition to storing the data in the array as a numeric index, you can also store the data as an associative index, using the field name as key name. That is to say, the result he gets is like an array, and the value can be obtained using key or index, so
while($row = mysql_fetch_array($res)){
echo $row['cid'].': :'.$row[1].";
}//Here $row['cid'], $row[1] can get the corresponding value.
mysql_fetch_object, as the name suggests, gets a row from the result set As an object, the field name is used as an attribute, so only in this way can the value be obtained
while($row = mysql_fetch_object($res)){
echo $row->cid.'::'.$ row->title."";
}
mysql_fetch_assoc, obtains a row from the result set as an associative array, which means that this function cannot use the index to obtain the value like mysql_fetch_row, but can only use the field name to obtain the value. So
while($row = mysql_fetch_assoc($res)){
echo $row['cid'].'::'.$row[1].";
} //$row[ 1] You cannot get the value in this way
Additional point:
The mysql_fetch_array function is defined like this: array mysql_fetch_array (resource result [, int result_type]), returns an array generated based on the rows obtained from the result set, if Returns FALSE if there are no more rows.
The optional second parameter result_type in mysql_fetch_array() is a constant that can accept the following values: MYSQL_ASSOC, MYSQL_NUM and MYSQL_BOTH. Among them:
1. mysql_fetch_assoc($result)==mysql_fetch_array($result,MYSQL_ASSOC);
2. mysql_fetch_row($result)==mysql_fetch_array($result,MYSQL_NUM);
So the mysql_fetch_array() function To some extent, it can be regarded as a collection of mysql_fetch_row() and mysql_fetch_assoc(). In addition, mysql_fetch_array() also has the MYSQL_BOTH parameter, which will result in an array containing both associations and numeric indexes.
Let’s say $row = $db->fetch_array($query);
$db is the human database operation class, $db->fetch_array($query), fetch_array($query) is that The method in the db class, $row = $db->fetch_array($query), means to get a row of records in the database from the recordset $query.
It can be implemented like this without classes

Copy the code The code is as follows:

$conn=@mysql_connect($host,$ user,$pass);
@mysql_select_db($database,$conn);
$query=mysql_query($sql);
while($row=mysql_fetch_array($query)){
$ rows[]=$row;
}

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