Php/docs/function.oci-set-prefetch
oci_set_prefetch
(PHP 5, PHP 7, PECL OCI8 >= 1.1.0)
oci_set_prefetch — 设置预提取行数
说明
oci_set_prefetch
( resource $statement
[, int $rows
] ) : bool
在成功调用 oci_execute()
之后设定预提取的行数。rows 的默认值为 1。
Note:
在 PHP 5.0.0 之前的版本必须使用 ocisetprefetch() 替代本函数。该函数名仍然可用，为向下兼容作为 oci_set_prefetch() 的别名。不过其已被废弃，不推荐使用。
成功时返回 true， 或者在失败时返回 false。
参见 oci8_.default_prefetch INI 选项。
参数
statement- 有效的 OCI8 报表标识符 由 oci_parse() 创建，被 oci_execute() 或
REF CURSORstatement 标识执行。 rows- The number of rows to be prefetched, >= 0
返回值
成功时返回 true， 或者在失败时返回 false。
更新日志
| 版本 | 说明 |
|---|---|
| PHP 5.3.2 (PECL OCI8 1.4) | Before this release, rows must be >= 1.
|
| PHP 5.3 (PECL OCI8 1.3.4) | Before this release, prefetching was limited to the lesser
of
restriction has now been removed. |
范例
Example #1 Changing the default prefetch value for a query
<?php$conn = oci_connect('hr', 'welcome', 'localhost/XE');$stid = oci_parse($conn, 'SELECT * FROM myverybigtable');oci_set_prefetch($stid, 300); // Set before calling oci_execute()oci_execute($stid);echo "<table border='1'>\n";while ($row = oci_fetch_array($stid, OCI_ASSOC+OCI_RETURN_NULLS)) { echo "<tr>\n"; foreach ($row as $item) { echo " <td>".($item !== null ? htmlentities($item, ENT_QUOTES) : " ")."</td>\n"; } echo "</tr>\n";}echo "</table>\n";oci_free_statement($stid);oci_close($conn);?>
Example #2 Changing the default prefetch for a REF CURSOR fetch
<?php/* Create the PL/SQL stored procedure as: CREATE OR REPLACE PROCEDURE myproc(p1 OUT SYS_REFCURSOR) AS BEGIN OPEN p1 FOR SELECT * FROM all_objects WHERE ROWNUM < 5000; END;*/$conn = oci_connect('hr', 'welcome', 'localhost/XE');$stid = oci_parse($conn, 'BEGIN myproc(:rc); END;');$refcur = oci_new_cursor($conn);oci_bind_by_name($stid, ':rc', $refcur, -1, OCI_B_CURSOR);oci_execute($stid);// Change the prefetch before executing the cursor.// REF CURSOR prefetching works when PHP is linked with Oracle 11gR2 Client librariesoci_set_prefetch($refcur, 200);oci_execute($refcur);echo "<table border='1'>\n";while ($row = oci_fetch_array($refcur, OCI_ASSOC+OCI_RETURN_NULLS)) { echo "<tr>\n"; foreach ($row as $item) { echo " <td>".($item !== null ? htmlentities($item, ENT_QUOTES) : " ")."</td>\n"; } echo "</tr>\n";}echo "</table>\n";oci_free_statement($refcur);oci_free_statement($stid);oci_close($conn);?>
If PHP OCI8 fetches from a REF CURSOR and then passes the REF
CURSOR back to a second PL/SQL procedure for further processing,
then set the REF CURSOR prefetch count to 0 to
avoid rows being "lost" from the result set. The prefetch value is
the number of extra rows fetched in each OCI8 internal request to
the database, so setting it to 0 means only
fetch one row at a time.
Example #3 Setting the prefetch value when passing a REF CURSOR back to Oracle
<?php$conn = oci_connect('hr', 'welcome', 'localhost/orcl');// get the REF CURSOR$stid = oci_parse($conn, 'BEGIN myproc(:rc_out); END;');$refcur = oci_new_cursor($conn);oci_bind_by_name($stid, ':rc_out', $refcur, -1, OCI_B_CURSOR);oci_execute($stid);// Display two rows, but don't prefetch any extra rows otherwise// those extra rows would not be passed back to myproc_use_rc().// A prefetch value of 0 is allowed in PHP 5.3.2 and PECL OCI8 1.4oci_set_prefetch($refcur, 0);oci_execute($refcur);$row = oci_fetch_array($refcur);var_dump($row);$row = oci_fetch_array($refcur);var_dump($row);// pass the REF CURSOR to myproc_use_rc() to do more data processing// with the result set$stid = oci_parse($conn, 'begin myproc_use_rc(:rc_in); end;'); oci_bind_by_name($stid, ':rc_in', $refcur, -1, OCI_B_CURSOR);oci_execute($stid);?>
注释
Note:
In PHP versions before 5.0.0 use ocisetprefetch() instead.
