mysql| Function | data | database | detailed 5 int mysql_data_seek (int result_id, int row_num);
Each result set returned by the Select query has a row cursor that indicates which row the next function (Mysql_fetch_array (), mysql_fetch_object (), or mysql_fetch_row ()) calls will return. Mysql_data_seek () Sets the pointer for the given result set to the given row. Line numbers range from 0 to mysql_num_rows ()-1. If the line number is valid, Mysql_data_seek () returns True, otherwise the return is false.
<?php
$link =mysql_pconnect ("localhost", "Sunsoft", "Suixiang") or Die ("could not Connect");
mysql_select_db ("samp_db") or Die ("could not select Database");
$query = "Select Last_name,first_name from President");
$result =mysql_query ($query) or Die ("Query failed");
For ($i =mysql_num_rows ($result)-1; $i >=0; $i-)
{
if (!mysql_data_seek ($result, $i);
{
printf ("Cannot seek to row%dn", $i);
Continue
}
if (! $row =mysql_fetch_object ($result)))
Continue
printf ("%d%s<br>n", $row->last_name, $row->first_name);
}
Mysql_free_result ($result);
?>
(6) Int mysql_db_query (string db_name, string query [, int link_id]);
Mysql_db_query () is similar to mysql_query () in addition to extracting an additional database name parameter and making it the default database before executing the query.
<?php
$link =mysql_pconnect ("localhost", "Sunsoft", "Suixiang") or Die ("could not Connect");
Print ("Connected successfully");
$query = "SELECT * from President";
$result =mysql_db_query ("samp_db", $query) or Die ("Query failed");
?>
(7) int mysql_drop_db (string db_name, int [link_id]);
Tells the MySQL server identified by link_id to delete the database with the given name. Returns true if the database deletion is successful, or False if an error occurs. You must have drop permissions on the database for deletion.
Be careful with this function; If you delete the database, it does not exist and cannot be recovered.
Using mysql_query () is more appropriate than using mysql_drop_db () to publish a drop DATABASE statement.
<?php
$link =mysql_pconnect ("localhost", "Sunsoft", "Suixiang") or Die ("could not Connect");
if (mysql_drop_db ("my_db"))
Print ("Database dropped Successfullyn");
Else
printf ("Error dropping Database:%sn", mysql_error ());
?>
(8) int mysql_errno (int [link_id]);
For a given connection, returns the error number of the MySQL-related function that contains the most recent return status. A value of 0 means that no error has occurred.
Usage examples
<?php
$link =mysql_pconnect ("localhost", "Sunsoft", "Suixiang") or Die ("could not Connect");
Print ("Connected successfully");
$query = "SELECT * from President";
$result =mysql_query ($query) or Die ("Query Failed,error code=". Mysql_errno ());
?>
