db2_lob_read(resource $stmt, int $colnum, int $length): string|false

使用 db2_lob_read（） 循环访问 结果集并检索用户定义的 LOB 数据大小。

参数 

stmt

包含 LOB 数据的有效资源。stmt

colnum

资源结果集中的有效列号。stmt

length

要从资源中检索的 LOB 数据的大小。stmt

返回值 

返回用户指定的数据量。如果无法检索数据，则返回 false。

示例 

示例 #1 遍历不同类型的数据

<?php

/* Database Connection Parameters */
$db = 'SAMPLE';
$username = 'db2inst1';
$password = 'ibmdb2';

/* Obtain Connection Resource */
$conn = db2_connect($db,$username,$password);

if ($conn) {
    $drop = 'DROP TABLE clob_stream';
    $result = @db2_exec( $conn, $drop );

    $create = 'CREATE TABLE clob_stream (id INTEGER, my_clob CLOB)';
    $result = db2_exec( $conn, $create );

    $variable = "";
    $stmt = db2_prepare($conn, "INSERT INTO clob_stream (id,my_clob) VALUES (1, ?)");
    $variable = "THIS IS A CLOB TEST. THIS IS A CLOB TEST.";
    db2_bind_param($stmt, 1, "variable", DB2_PARAM_IN);
    db2_execute($stmt);

    $sql = "SELECT id,my_clob FROM clob_stream";
    $result = db2_prepare($conn, $sql);
    db2_execute($result);
    db2_fetch_row($result);
    $i = 0;
    /* Read LOB data */
    while ($data = db2_lob_read($result, 2, 6)) {
        echo "Loop $i: $data\n";
        $i = $i + 1;
    }

    $drop = 'DROP TABLE blob_stream';
    $result = @db2_exec( $conn, $drop );

    $create = 'CREATE TABLE blob_stream (id INTEGER, my_blob CLOB)';
    $result = db2_exec( $conn, $create );

    $variable = "";
    $stmt = db2_prepare($conn, "INSERT INTO blob_stream (id,my_blob) VALUES (1, ?)");
    $variable = "THIS IS A BLOB TEST. THIS IS A BLOB TEST.";
    db2_bind_param($stmt, 1, "variable", DB2_PARAM_IN);
    db2_execute($stmt);

    $sql = "SELECT id,my_blob FROM blob_stream";
    $result = db2_prepare($conn, $sql);
    db2_execute($result);
    db2_fetch_row($result);
    $i = 0;
    /* Read LOB data */
    while ($data = db2_lob_read($result, 2, 6)) {
        echo "Loop $i: $data\n";
        $i = $i + 1;
    }
} else {
    echo 'no connection: ' . db2_conn_errormsg();
}

?>

以上示例会输出：

Loop 0: THIS I
Loop 1: S A CL
Loop 2: OB TES
Loop 3: T. THI
Loop 4: S IS A
Loop 5:  CLOB 
Loop 6: TEST.
Loop 0: THIS I
Loop 1: S A BL
Loop 2: OB TES
Loop 3: T. THI
Loop 4: S IS A
Loop 5:  BLOB 
Loop 6: TEST.

参见 

• db2_bind_param（） - 将 PHP 变量绑定到 SQL 语句参数
• db2_exec（） - 直接执行 SQL 语句
• db2_execute（） - 执行准备好的 SQL 语句
• db2_fetch_row（） - 将结果集指针设置为下一行或请求的行
• db2_prepare（） - 准备要执行的 SQL 语句
• db2_result（） - 从结果集中的一行返回一列