初始化新的空 LOB 或 FILE 描述符

# oci_new_descriptor

(PHP 5, PHP 7, PHP 8, PECL OCI8 >= 1.1.0)

oci_new_descriptor — 初始化新的空 LOB 或 FILE 描述符

### 说明

function oci_new_descriptor(resource `$connection`, int `$type` = `OCI_DTYPE_LOB`): ?OCILob

分配保存描述符或 LOB 定位器的资源。

### 参数

`connection`

  Oracle 连接标识符，由 oci_connect() 或 oci_pconnect() 返回。

`type`

  `type` 的有效值是：`OCI_DTYPE_FILE`、`OCI_DTYPE_LOB` 和 `OCI_DTYPE_ROWID`。

### 返回值

成功时返回新 LOB 或 FILE 描述符，失败时为 `null`。

### 示例

示例 #1 oci_new_descriptor() 示例

    <?php
    /* This script is designed to be called from a HTML form.
     * It expects $user, $password, $table, $where, and $commitsize
     * to be passed in from the form.  The script then deletes
     * the selected rows using the ROWID and commits after each
     * set of $commitsize rows. (Use with care, there is no rollback)
     */
    $conn = oci_connect($user, $password);
    $stmt = oci_parse($conn, "select rowid from $table $where");
    $rowid = oci_new_descriptor($conn, OCI_D_ROWID);
    oci_define_by_name($stmt, "ROWID", $rowid);
    oci_execute($stmt);
    while (oci_fetch($stmt)) {
        $nrows = oci_num_rows($stmt);
        $delete = oci_parse($conn, "delete from $table where ROWID = :rid");
        oci_bind_by_name($delete, ":rid", $rowid, -1, OCI_B_ROWID);
        oci_execute($delete);
        echo "$nrows\n";
        if (($nrows % $commitsize) == 0) {
            oci_commit($conn);
        }
    }
    $nrows = oci_num_rows($stmt);
    echo "$nrows deleted...\n";
    oci_free_statement($stmt);
    oci_close($conn);
    ?>

    <?php
        /* This script demonstrates file upload to LOB columns
         * The formfield used for this example looks like this
         * <form action="upload.php" method="post" enctype="multipart/form-data">
         * <input type="file" name="lob_upload" />
         * ...
         */
      if (!isset($lob_upload) || $lob_upload == 'none'){
    ?>
    <form action="upload.php" method="post" enctype="multipart/form-data">
    Upload file: <input type="file" name="lob_upload" /><br />
    <input type="submit" value="Upload" /> - <input type="reset" value="Reset" />
    </form>
    <?php
      } else {

         // $lob_upload contains the temporary filename of the uploaded file

         // see also the features section on file upload,
         // if you would like to use secure uploads

         $conn = oci_connect($user, $password);
         $lob = oci_new_descriptor($conn, OCI_D_LOB);
         $stmt = oci_parse($conn, "insert into $table (id, the_blob)
                   values(my_seq.NEXTVAL, EMPTY_BLOB()) returning the_blob into :the_blob");
         oci_bind_by_name($stmt, ':the_blob', $lob, -1, OCI_B_BLOB);
         oci_execute($stmt, OCI_DEFAULT);
         if ($lob->savefile($lob_upload)){
            oci_commit($conn);
            echo "Blob successfully uploaded\n";
         }else{
            echo "Couldn't upload Blob\n";
         }
         $lob->free();
         oci_free_statement($stmt);
         oci_close($conn);
      }
    ?>

示例 #2 oci_new_descriptor() 示例

    <?php
    /* Calling PL/SQL stored procedures which contain clobs as input
     * parameters.
     * Example PL/SQL stored procedure signature is:
     *
     * PROCEDURE save_data
     *   Argument Name                  Type                    In/Out Default?
     *   ------------------------------ ----------------------- ------ --------
     *   KEY                            NUMBER(38)              IN
     *   DATA                           CLOB                    IN
     *
     */

    $conn = oci_connect($user, $password);
    $stmt = oci_parse($conn, "begin save_data(:key, :data); end;");
    $clob = oci_new_descriptor($conn, OCI_D_LOB);
    oci_bind_by_name($stmt, ':key', $key);
    oci_bind_by_name($stmt, ':data', $clob, -1, OCI_B_CLOB);
    $clob->write($data);
    oci_execute($stmt, OCI_DEFAULT);
    oci_commit($conn);
    $clob->free();
    oci_free_statement($stmt);
    ?>

### 参见

- oci_bind_by_name() - 绑定 PHP 变量到 Oracle 位置标志符

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