MySQL database functions (2)

5) int mysql_data_seek (int result_id, int row_num );
Each result set returned by the SELECT query has a row cursor, indicating the row to be returned by the next function (mysql_fetch_array (), mysql_fetch_object (), or mysql_fetch_row () to extract the row. Mysql_data_seek () sets the pointer of the given result set to the given row. The row number ranges from 0 to mysql_num_rows ()-1. If the row number is valid, mysql_data_seek () returns true; otherwise, false.
<? Php
$ Link = mysql_pconnect ("localhost", "sunsoft", "suixiang") or die ("cocould not connect ");
Mysql_select_db ("samp_db") or die ("cocould 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]);
In addition to extracting an additional database name parameter, mysql_db_query () makes it the default database before executing the query, similar to mysql_query.
<? Php
$ Link = mysql_pconnect ("localhost", "sunsoft", "suixiang") or die ("cocould 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. If the database is successfully deleted, true is returned. If an error occurs, false is returned. You must have the DROP permission to delete the database.
Be careful with this function. If you delete a database, it does not exist and cannot be recovered.
Mysql_query () is more suitable for publishing the drop database statement using mysql_drop_db.
<? Php