Some commonly used php functions and examples

$DB_HOST ="localhost";
$DB_LOGIN ="root";
$DB_PASSWORD =" 123456";
$conn=mysql_connect($DB_HOST,$DB_LOGIN,$DB_PASSWORD);

mysql_data_seek Move the inner query pointer to the query row grammar bool mysql_data_seek(resource result_indetifier,int row_number) Example:

$DB_HOST ="localhost";
$DB_LOGIN ="root";
$DB_PASSWORD ="123456";
$DB_NAME ="flag";
$conn=mysql_connect($DB_HOST ,$DB_LOGIN,$DB_PASSWORD);
mysql_select_db($DB_NAME);
$res=mysql_query("SELECT * FROM PRODUCT");
$row=mysql_fetch_array($res);
for($i=0;$i< $num;$i++)
$row=mysql_fetch_array($res);
mysql_data_seek($res,0);//Move the pointer back to the first row of the query result

mysql_fetch_array Store the query results in an array (each array element stores a record) grammar array mysql_fetch_array(resource result[,int result_type]) Example:

$DB_HOST ="localhost";
$DB_LOGIN ="root";
$DB_PASSWORD ="123456";
$DB_NAME ="flag";
$conn=mysql_connect($DB_HOST ,$DB_LOGIN,$DB_PASSWORD);
mysql_select_db($DB_NAME);
$res=mysql_query("SELECT * FROM PRODUCT");
$row=mysql_fetch_array($res);

mysql_fetch _object Obtain a row of query results and store it as an object type. The usage method is exactly the same as MySQL_fetch_array(). The difference is that mysql_fetch_object() can only obtain query results through field names. echo $row->fieldname; //Correct usage echo $row->0; //wrong usage grammar object mysql_fetch_object(resource result) Example:

$DB_HOST ="localhost";
$DB_LOGIN ="root";
$DB_PASSWORD ="123456";
$DB_NAME ="flag";
$conn=mysql_connect($DB_HOST ,$DB_LOGIN,$DB_PASSWORD);
mysql_select_db($DB_NAME);
$res=mysql_query("SELECT * FROM PRODUCT");
$row=$mysql_fetch_object($res);
while($row)
{
echo $rowàp_id;
echo $rowàp_name;
}

mysql_insert_id After using the INSERT command to add a piece of information, you can use this function to obtain the unique id of the record just added. grammar int mysql_insert_id([esource link_identifier]) Example:

$DB_HOST ="localhost";
$DB_LOGIN ="root";
$DB_PASSWORD ="123456";
$DB_NAME ="flag";
$conn=mysql_connect($DB_HOST ,$DB_LOGIN,$DB_PASSWORD);
mysql_select_db($DB_NAME);
$SQLStr"INSERT INTO produce (p_id,p_name)VALUES('','PHP book')";
$res=mysql_query($res);
 $p_id=mysql_insert_id();

mysql_num_rows Get how many rows there are in the query results grammar int mysql_num_rows(resource result) Example:

$DB_HOST ="localhost";
$DB_LOGIN ="root";
$DB_PASSWORD ="123456";
$DB_NAME ="flag";
$conn=mysql_connect($DB_HOST ,$DB_LOGIN,$DB_PASSWORD);
mysql_select_db($DB_NAME);
$res=mysql_query("SELECT * FROM PRODUCT");
$num=mysql_num_rows($res);

mysql_query Send a SQL syntax query statement grammar resource mysql_query(string query[,resource link_identifier]) Example:

$DB_HOST ="localhost";
$DB_LOGIN ="root";
$DB_PASSWORD="123456";
$DB_NAME ="flag";
$conn=mysql_connect($DB_HOST ,$DB_LOGIN,$DB_PASSWORD);
mysql_select_db($DB_NAME);
$res=mysql_query("SELECT * FROM PRODUCT");

mysql_select_db Select the name of the database you want to access grammar bool mysql_select_db(string database_name[,resource link_identifier]) Example:

$DB_HOST ="localhost";
$DB_LOGIN ="root";
$DB_PASSWORD ="123456";
$DB_NAME ="flag";
$conn=mysql_connect($DB_HOST ,$DB_LOGIN,$DB_PASSWORD);
mysql_select_db($DB_NAME);

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