一次编写，随处运行

Listing 1 shows an example use of prepared queries. These can be quite convenient if you have to run a number of queries where the only difference is in the data that is being passed to the database while the structure of the query remains the same. Advanced databases can store the parsed query in memory to offer a performance boost.
Listing 1 展示了一个使用预准备的查询的例子。如果你必须运行大量查询而唯一的差别是数据传递给数据库，但是查询的结构还是一样的，这些能够相当的方便。高级的数据库能够在内存中储存解析好的查询来加速性能。

Listing 1

$alldata = array(
array(1, ''one'', ''un''),
array(2, ''two'', ''deux''),
array(3, ''three'', ''trois''),
array(4, ''four'', ''quatre'')
);

$p_query = $mdb->prepareQuery(''INSERT INTO numbers VALUES (?,?,?)'');
$param_types = array(''integer'', ''text'', ''text'');

foreach ($alldata as $row) {
$mdb->execute($p_query, NULL, $row, $param_types);
}

Each of the 4 arrays that are stored in $alldata will be used in an execute statement. The data will automatically be converted to the correct format. Since this is an insert statement the second parameter for MDB::execute() is set to NULL because we will not have any result columns for which we would need to set data types.
在 $alldata 中储存的所有四个数组将用于 execute 语句。数据将自动被转换为正确的格式。因为这是一个插入语句，MDB::execute() 的第二个参数被设置为 NULL 因为我们将没有任何结果列需要我们设置数据类型。

Among the supported data type are also LOB''s (Large OBjects) which allow you to store files into a database. Binary files are stored in BLOBs (Binary Large OBject) and normal text files are stored on CLOBs (Character Large OBject). In MDB you can only store LOB''s using prepared INSERT and UPDATE queries. Using either MDB::setParamBlob() or MDB::setParamClob() you can set the values of the LOB field in a prepared query. Both methods expect to be passed a LOB object however which can be created using MDB::createLob().
在支持的数据类型中还有 LOB （大对象），它使得我们能够在数据库中储存文件。二进制文件储存在 BLOB （二进制大对象）中而且普通文本文件储存在 CLOB （字符大对象）中。在 MDB 中你仅仅能够使用预准备的 INSERT 和 UPDATE 查询储存 LOB。使用 MDBA::setParamBlob() 或者 MDB::setParamClob() 你能够设置预准备查询的 LOB 域的值。两个函数都预期传递一个 LOB 对象，而它能够使用 MDB::createLob() 创建。

$binary_lob = array(
''Type'' => ''inputfile'',
''FileName'' => ''./myfile.gif''
);
$blob = $mdb->createLob($binary_lob);

$character_lob = array(
''Type'' => ''data'',
''Data'' => ''this would be a very long string container the CLOB data''
);
$clob = $mdb->createLob($character_lob);

As you can see MDB::createLob() is passed an asso

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