关于PEAR DB的使用

xinxing520

通过 Pear DB可以从查询结果获得更多有用的数据信息 。这些方法有:
numRows(): 通过一个"SELECT" 查询返回所有数据的数量。
numCols():通过一个"SELECT" 查询返回所有的列。
affectedRows(): 通过("INSERT", "UPDATE" or "DELETE"操作返回所有受影响的数据行数。
tableInfo():通过一个"SELECT" 查询返回一个包含数据信息的数组sexinsex。
可用方法列表：
<?php /* * From the DB_(driver) objects */ // get the object with, ie: $db = DB::connect('mysql://user:pass@localhost/my_db');   // Set options $db->setErrorHandling(); $db->setFetchmode(); // Information $db->affectedRows(); $db->tableInfo(); // Database manipulation $db->query(); // Data fetch $db->nextId(); $db->getOne(); $db->getRow(); $db->getCol(); $db->getAssoc(); $db->getAll(); // Place holders and execute related $db->quote(); $db->prepare(); $db->execute(); $db->executeMultiple(); // Transactions $db->autoCommit(); $db->commit(); $db->rollback(); // Disconnection $db->disconnect();   /* * From DB_result objects */ // get the object with, ie:  $res = $db->query('select * from foo');   // Data fetch $res->fetchRow(); $res->fetchInto(); // Result Info $res->numCols(); $res->numRows(); $res->tableInfo(); // Free $res->free();   /* * From DB_error objects */ // get the object with, ie: $error = $db->query('select * from no_table');   $error->getMessage(); $error->getDebugInfo(); $error->toString(); ?>
/////////////////////////////////////////////////其他详就去干细使用///////////////////////////////////////////////PEAR DB 的连接和断开

<?php // The pear base directory must be in your include_path require_once 'DB.php'; $user = 'foo'; $pass = 'bar'; $host = 'localhost'; $db_name = 'clients_db';  // Data Source Name: This is the universal connection string $dsn = "mysql://$userpass@$host/$db_name";  // DB::connect will return a Pear DB object on success // or a Pear DB Error object on error // You can also set to TRUE the second param // if you want a persistent connection: // $db = DB::connect($dsn, true); $db = DB::connect($dsn);  // With DB::isError you can differentiate between an error or // a valid connection. if (DB::isError($db)) {         die ($db->getMessage()); } .... // You can disconnect from the database with: $db->disconnect(); ?>=======================执行数据库并获得数据<?php // Once you have a valid DB object ... $sql = "select * from clients"; // If the query is a "SELECT", $db->query will return // a DB Result object on success. // Else it simply will return a DB_OK // On failure it will return a DB Error object. $result = $db->query($sql); // Always check that $result is not an error if (DB::isError($result)) {         die ($result->getMessage()); }  // Once you have a valid DB Result object ... // Get each row of data on each iteration until // there is no more rows while ($row = $result->fetchRow()) {     $id = $row[0]; }  ?>===============================选择获取数据的格式<?php $res = $db->query('select id, name, email from users'); $row = $res->fetchRow($mode);  //With $mode = DB_FETCHMODE_ORDERED //The default behavior is to return an ordered array. $row = array (     0 => <column "id" data>,     1 => <column "name" data>,     2 => <column "email" data> );  $id = $row[0];  //With $mode = DB_FETCHMODE_ASSOC //Returns an associative array with column names as array keys: $row = array (     'id'    => <column "id" data>,     'name'  => <column "name" data>,     'email' => <column "email" data> );  $id = $row['id'];  //With $mode = DB_FETCHMODE_OBJECT //Returns a DB_row object with column names as properties: $row = db_row Object  (     [id]    => <column "id" data>,     [name]  => <column "name" data>,     [email] => <column "email" data> )  $id = $row->id; ?>=============================控制获取数据的数量 <?php ... // the row to start fetching $from = 50; // how many results per page $res_per_page = 10; // the last row to fetch for this page $to = $from + $res_per_page; foreach (range($from, $to) as $rownum) {     if (!$row = $res->fetchrow($fetchmode, $rownum)) {         break;     }     $id = $row[0];     .... } ?>===========================清楚结果释放变量<?php ... $result = $db->query('SELECT * FROM clients'); while ($row = $result->fetchRow()) {     ... } $result->free(); ?>===========================
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